Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

86 files changed, 28724 insertions, 0 deletions

diff --git a/src/rocksdb/tools/CMakeLists.txt b/src/rocksdb/tools/CMakeLists.txt
new file mode 100644
index 00000000..6c4733a7
--- /dev/null
+++ b/src/rocksdb/tools/CMakeLists.txt
@@ -0,0 +1,21 @@
+set(TOOLS
+  sst_dump.cc
+  db_sanity_test.cc
+  db_stress.cc
+  write_stress.cc
+  ldb.cc
+  db_repl_stress.cc
+  dump/rocksdb_dump.cc
+  dump/rocksdb_undump.cc)
+foreach(src ${TOOLS})
+  get_filename_component(exename ${src} NAME_WE)
+  add_executable(${exename}${ARTIFACT_SUFFIX}
+    ${src})
+  target_link_libraries(${exename}${ARTIFACT_SUFFIX} ${LIBS})
+  list(APPEND tool_deps ${exename})
+endforeach()
+add_custom_target(tools
+  DEPENDS ${tool_deps})
+add_custom_target(ldb_tests
+  COMMAND python ${CMAKE_CURRENT_SOURCE_DIR}/ldb_tests.py
+  DEPENDS ldb)
diff --git a/src/rocksdb/tools/Dockerfile b/src/rocksdb/tools/Dockerfile
new file mode 100644
index 00000000..1d5ead7f
--- /dev/null
+++ b/src/rocksdb/tools/Dockerfile
@@ -0,0 +1,5 @@
+FROM buildpack-deps:wheezy
+
+ADD ./ldb /rocksdb/tools/ldb
+
+CMD /rocksdb/tools/ldb
diff --git a/src/rocksdb/tools/advisor/README.md b/src/rocksdb/tools/advisor/README.md
new file mode 100644
index 00000000..f1e7165e
--- /dev/null
+++ b/src/rocksdb/tools/advisor/README.md
@@ -0,0 +1,96 @@
+# Rocksdb Tuning Advisor
+
+## Motivation
+
+The performance of Rocksdb is contingent on its tuning. However,
+because of the complexity of its underlying technology and a large number of
+configurable parameters, a good configuration is sometimes hard to obtain. The aim of
+the python command-line tool, Rocksdb Advisor, is to automate the process of
+suggesting improvements in the configuration based on advice from Rocksdb
+experts.
+
+## Overview
+
+Experts share their wisdom as rules comprising of conditions and suggestions in the INI format (refer
+[rules.ini](https://github.com/facebook/rocksdb/blob/master/tools/advisor/advisor/rules.ini)).
+Users provide the Rocksdb configuration that they want to improve upon (as the
+familiar Rocksdb OPTIONS file —
+[example](https://github.com/facebook/rocksdb/blob/master/examples/rocksdb_option_file_example.ini))
+and the path of the file which contains Rocksdb logs and statistics.
+The [Advisor](https://github.com/facebook/rocksdb/blob/master/tools/advisor/advisor/rule_parser_example.py)
+creates appropriate DataSource objects (for Rocksdb
+[logs](https://github.com/facebook/rocksdb/blob/master/tools/advisor/advisor/db_log_parser.py),
+[options](https://github.com/facebook/rocksdb/blob/master/tools/advisor/advisor/db_options_parser.py),
+[statistics](https://github.com/facebook/rocksdb/blob/master/tools/advisor/advisor/db_stats_fetcher.py) etc.)
+and provides them to the [Rules Engine](https://github.com/facebook/rocksdb/blob/master/tools/advisor/advisor/rule_parser.py).
+The Rules uses rules from experts to parse data-sources and trigger appropriate rules.
+The Advisor's output gives information about which rules were triggered,
+why they were triggered and what each of them suggests. Each suggestion
+provided by a triggered rule advises some action on a Rocksdb
+configuration option, for example, increase CFOptions.write_buffer_size,
+set bloom_bits to 2 etc.
+
+## Usage
+
+### Prerequisites
+The tool needs the following to run:
+* python3
+
+### Running the tool
+An example command to run the tool:
+
+```shell
+cd rocksdb/tools/advisor
+python3 -m advisor.rule_parser_example --rules_spec=advisor/rules.ini --rocksdb_options=test/input_files/OPTIONS-000005 --log_files_path_prefix=test/input_files/LOG-0 --stats_dump_period_sec=20
+```
+
+### Command-line arguments
+
+Most important amongst all the input that the Advisor needs, are the rules
+spec and starting Rocksdb configuration. The configuration is provided as the
+familiar Rocksdb Options file (refer [example](https://github.com/facebook/rocksdb/blob/master/examples/rocksdb_option_file_example.ini)).
+The Rules spec is written in the INI format (more details in
+[rules.ini](https://github.com/facebook/rocksdb/blob/master/tools/advisor/advisor/rules.ini)).
+
+In brief, a Rule is made of conditions and is triggered when all its
+constituent conditions are triggered. When triggered, a Rule suggests changes
+(increase/decrease/set to a suggested value) to certain Rocksdb options that
+aim to improve Rocksdb performance. Every Condition has a 'source' i.e.
+the data source that would be checked for triggering that condition.
+For example, a log Condition (with 'source=LOG') is triggered if a particular
+'regex' is found in the Rocksdb LOG files. As of now the Rules Engine
+supports 3 types of Conditions (and consequently data-sources):
+LOG, OPTIONS, TIME_SERIES. The TIME_SERIES data can be sourced from the
+Rocksdb [statistics](https://github.com/facebook/rocksdb/blob/master/include/rocksdb/statistics.h)
+or [perf context](https://github.com/facebook/rocksdb/blob/master/include/rocksdb/perf_context.h).
+
+For more information about the remaining command-line arguments, run:
+
+```shell
+cd rocksdb/tools/advisor
+python3 -m advisor.rule_parser_example --help
+```
+
+### Sample output
+
+Here, a Rocksdb log-based rule has been triggered:
+
+```shell
+Rule: stall-too-many-memtables
+LogCondition: stall-too-many-memtables regex: Stopping writes because we have \d+ immutable memtables \(waiting for flush\), max_write_buffer_number is set to \d+
+Suggestion: inc-bg-flush option : DBOptions.max_background_flushes action : increase suggested_values : ['2']
+Suggestion: inc-write-buffer option : CFOptions.max_write_buffer_number action : increase
+scope: col_fam:
+{'default'}
+```
+
+## Running the tests
+
+Tests for the code have been added to the
+[test/](https://github.com/facebook/rocksdb/tree/master/tools/advisor/test)
+directory. For example, to run the unit tests for db_log_parser.py:
+
+```shell
+cd rocksdb/tools/advisor
+python3 -m unittest -v test.test_db_log_parser
+```
diff --git a/src/rocksdb/tools/advisor/advisor/__init__.py b/src/rocksdb/tools/advisor/advisor/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/__init__.py
diff --git a/src/rocksdb/tools/advisor/advisor/bench_runner.py b/src/rocksdb/tools/advisor/advisor/bench_runner.py
new file mode 100644
index 00000000..7c7ee788
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/bench_runner.py
@@ -0,0 +1,39 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from abc import ABC, abstractmethod
+import re
+
+
+class BenchmarkRunner(ABC):
+    @staticmethod
+    @abstractmethod
+    def is_metric_better(new_metric, old_metric):
+        pass
+
+    @abstractmethod
+    def run_experiment(self):
+        # should return a list of DataSource objects
+        pass
+
+    @staticmethod
+    def get_info_log_file_name(log_dir, db_path):
+        # Example: DB Path = /dev/shm and OPTIONS file has option
+        # db_log_dir=/tmp/rocks/, then the name of the log file will be
+        # 'dev_shm_LOG' and its location will be /tmp/rocks. If db_log_dir is
+        # not specified in the OPTIONS file, then the location of the log file
+        # will be /dev/shm and the name of the file will be 'LOG'
+        file_name = ''
+        if log_dir:
+            # refer GetInfoLogPrefix() in rocksdb/util/filename.cc
+            # example db_path: /dev/shm/dbbench
+            file_name = db_path[1:]  # to ignore the leading '/' character
+            to_be_replaced = re.compile('[^0-9a-zA-Z\-_\.]')
+            for character in to_be_replaced.findall(db_path):
+                file_name = file_name.replace(character, '_')
+            if not file_name.endswith('_'):
+                file_name += '_'
+        file_name += 'LOG'
+        return file_name
diff --git a/src/rocksdb/tools/advisor/advisor/config_optimizer_example.py b/src/rocksdb/tools/advisor/advisor/config_optimizer_example.py
new file mode 100644
index 00000000..e3736387
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/config_optimizer_example.py
@@ -0,0 +1,134 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+import argparse
+from advisor.db_config_optimizer import ConfigOptimizer
+from advisor.db_log_parser import NO_COL_FAMILY
+from advisor.db_options_parser import DatabaseOptions
+from advisor.rule_parser import RulesSpec
+
+
+CONFIG_OPT_NUM_ITER = 10
+
+
+def main(args):
+    # initialise the RulesSpec parser
+    rule_spec_parser = RulesSpec(args.rules_spec)
+    # initialise the benchmark runner
+    bench_runner_module = __import__(
+        args.benchrunner_module, fromlist=[args.benchrunner_class]
+    )
+    bench_runner_class = getattr(bench_runner_module, args.benchrunner_class)
+    ods_args = {}
+    if args.ods_client and args.ods_entity:
+        ods_args['client_script'] = args.ods_client
+        ods_args['entity'] = args.ods_entity
+        if args.ods_key_prefix:
+            ods_args['key_prefix'] = args.ods_key_prefix
+    db_bench_runner = bench_runner_class(args.benchrunner_pos_args, ods_args)
+    # initialise the database configuration
+    db_options = DatabaseOptions(args.rocksdb_options, args.misc_options)
+    # set the frequency at which stats are dumped in the LOG file and the
+    # location of the LOG file.
+    db_log_dump_settings = {
+        "DBOptions.stats_dump_period_sec": {
+            NO_COL_FAMILY: args.stats_dump_period_sec
+        }
+    }
+    db_options.update_options(db_log_dump_settings)
+    # initialise the configuration optimizer
+    config_optimizer = ConfigOptimizer(
+        db_bench_runner,
+        db_options,
+        rule_spec_parser,
+        args.base_db_path
+    )
+    # run the optimiser to improve the database configuration for given
+    # benchmarks, with the help of expert-specified rules
+    final_db_options = config_optimizer.run()
+    # generate the final rocksdb options file
+    print(
+        'Final configuration in: ' +
+        final_db_options.generate_options_config('final')
+    )
+    print(
+        'Final miscellaneous options: ' +
+        repr(final_db_options.get_misc_options())
+    )
+
+
+if __name__ == '__main__':
+    '''
+    An example run of this tool from the command-line would look like:
+    python3 -m advisor.config_optimizer_example
+    --base_db_path=/tmp/rocksdbtest-155919/dbbench
+    --rocksdb_options=temp/OPTIONS_boot.tmp --misc_options bloom_bits=2
+    --rules_spec=advisor/rules.ini --stats_dump_period_sec=20
+    --benchrunner_module=advisor.db_bench_runner
+    --benchrunner_class=DBBenchRunner --benchrunner_pos_args ./../../db_bench
+    readwhilewriting use_existing_db=true duration=90
+    '''
+    parser = argparse.ArgumentParser(description='This script is used for\
+        searching for a better database configuration')
+    parser.add_argument(
+        '--rocksdb_options', required=True, type=str,
+        help='path of the starting Rocksdb OPTIONS file'
+    )
+    # these are options that are column-family agnostic and are not yet
+    # supported by the Rocksdb Options file: eg. bloom_bits=2
+    parser.add_argument(
+        '--misc_options', nargs='*',
+        help='whitespace-separated list of options that are not supported ' +
+        'by the Rocksdb OPTIONS file, given in the ' +
+        '<option_name>=<option_value> format eg. "bloom_bits=2 ' +
+        'rate_limiter_bytes_per_sec=128000000"')
+    parser.add_argument(
+        '--base_db_path', required=True, type=str,
+        help='path for the Rocksdb database'
+    )
+    parser.add_argument(
+        '--rules_spec', required=True, type=str,
+        help='path of the file containing the expert-specified Rules'
+    )
+    parser.add_argument(
+        '--stats_dump_period_sec', required=True, type=int,
+        help='the frequency (in seconds) at which STATISTICS are printed to ' +
+        'the Rocksdb LOG file'
+    )
+    # ODS arguments
+    parser.add_argument(
+        '--ods_client', type=str, help='the ODS client binary'
+    )
+    parser.add_argument(
+        '--ods_entity', type=str,
+        help='the servers for which the ODS stats need to be fetched'
+    )
+    parser.add_argument(
+        '--ods_key_prefix', type=str,
+        help='the prefix that needs to be attached to the keys of time ' +
+        'series to be fetched from ODS'
+    )
+    # benchrunner_module example: advisor.db_benchmark_client
+    parser.add_argument(
+        '--benchrunner_module', required=True, type=str,
+        help='the module containing the BenchmarkRunner class to be used by ' +
+        'the Optimizer, example: advisor.db_bench_runner'
+    )
+    # benchrunner_class example: DBBenchRunner
+    parser.add_argument(
+        '--benchrunner_class', required=True, type=str,
+        help='the name of the BenchmarkRunner class to be used by the ' +
+        'Optimizer, should be present in the module provided in the ' +
+        'benchrunner_module argument, example: DBBenchRunner'
+    )
+    parser.add_argument(
+        '--benchrunner_pos_args', nargs='*',
+        help='whitespace-separated positional arguments that are passed on ' +
+        'to the constructor of the BenchmarkRunner class provided in the ' +
+        'benchrunner_class argument, example: "use_existing_db=true ' +
+        'duration=900"'
+    )
+    args = parser.parse_args()
+    main(args)
diff --git a/src/rocksdb/tools/advisor/advisor/db_bench_runner.py b/src/rocksdb/tools/advisor/advisor/db_bench_runner.py
new file mode 100644
index 00000000..54424440
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/db_bench_runner.py
@@ -0,0 +1,245 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from advisor.bench_runner import BenchmarkRunner
+from advisor.db_log_parser import DataSource, DatabaseLogs, NO_COL_FAMILY
+from advisor.db_stats_fetcher import (
+    LogStatsParser, OdsStatsFetcher, DatabasePerfContext
+)
+import shutil
+import subprocess
+import time
+
+
+'''
+NOTE: This is not thread-safe, because the output file is simply overwritten.
+'''
+
+
+class DBBenchRunner(BenchmarkRunner):
+    OUTPUT_FILE = "temp/dbbench_out.tmp"
+    ERROR_FILE = "temp/dbbench_err.tmp"
+    DB_PATH = "DB path"
+    THROUGHPUT = "ops/sec"
+    PERF_CON = " PERF_CONTEXT:"
+
+    @staticmethod
+    def is_metric_better(new_metric, old_metric):
+        # for db_bench 'throughput' is the metric returned by run_experiment
+        return new_metric >= old_metric
+
+    @staticmethod
+    def get_opt_args_str(misc_options_dict):
+        # given a dictionary of options and their values, return a string
+        # that can be appended as command-line arguments
+        optional_args_str = ""
+        for option_name, option_value in misc_options_dict.items():
+            if option_value:
+                optional_args_str += (
+                    " --" + option_name + "=" + str(option_value)
+                )
+        return optional_args_str
+
+    def __init__(self, positional_args, ods_args=None):
+        # parse positional_args list appropriately
+        self.db_bench_binary = positional_args[0]
+        self.benchmark = positional_args[1]
+        self.db_bench_args = None
+        if len(positional_args) > 2:
+            # options list with each option given as "<option>=<value>"
+            self.db_bench_args = positional_args[2:]
+        # save ods_args, if provided
+        self.ods_args = ods_args
+
+    def _parse_output(self, get_perf_context=False):
+        '''
+        Sample db_bench output after running 'readwhilewriting' benchmark:
+        DB path: [/tmp/rocksdbtest-155919/dbbench]\n
+        readwhilewriting : 16.582 micros/op 60305 ops/sec; 4.2 MB/s (3433828\
+        of 5427999 found)\n
+        PERF_CONTEXT:\n
+        user_key_comparison_count = 500466712, block_cache_hit_count = ...\n
+        '''
+        output = {
+            self.THROUGHPUT: None, self.DB_PATH: None, self.PERF_CON: None
+        }
+        perf_context_begins = False
+        with open(self.OUTPUT_FILE, 'r') as fp:
+            for line in fp:
+                if line.startswith(self.benchmark):
+                    # line from sample output:
+                    # readwhilewriting : 16.582 micros/op 60305 ops/sec; \
+                    # 4.2 MB/s (3433828 of 5427999 found)\n
+                    print(line)  # print output of the benchmark run
+                    token_list = line.strip().split()
+                    for ix, token in enumerate(token_list):
+                        if token.startswith(self.THROUGHPUT):
+                            # in above example, throughput = 60305 ops/sec
+                            output[self.THROUGHPUT] = (
+                                float(token_list[ix - 1])
+                            )
+                            break
+                elif get_perf_context and line.startswith(self.PERF_CON):
+                    # the following lines in the output contain perf context
+                    # statistics (refer example above)
+                    perf_context_begins = True
+                elif get_perf_context and perf_context_begins:
+                    # Sample perf_context output:
+                    # user_key_comparison_count = 500, block_cache_hit_count =\
+                    # 468, block_read_count = 580, block_read_byte = 445, ...
+                    token_list = line.strip().split(',')
+                    # token_list = ['user_key_comparison_count = 500',
+                    # 'block_cache_hit_count = 468','block_read_count = 580'...
+                    perf_context = {
+                        tk.split('=')[0].strip(): tk.split('=')[1].strip()
+                        for tk in token_list
+                        if tk
+                    }
+                    # TODO(poojam23): this is a hack and should be replaced
+                    # with the timestamp that db_bench will provide per printed
+                    # perf_context
+                    timestamp = int(time.time())
+                    perf_context_ts = {}
+                    for stat in perf_context.keys():
+                        perf_context_ts[stat] = {
+                            timestamp: int(perf_context[stat])
+                        }
+                    output[self.PERF_CON] = perf_context_ts
+                    perf_context_begins = False
+                elif line.startswith(self.DB_PATH):
+                    # line from sample output:
+                    # DB path: [/tmp/rocksdbtest-155919/dbbench]\n
+                    output[self.DB_PATH] = (
+                        line.split('[')[1].split(']')[0]
+                    )
+        return output
+
+    def get_log_options(self, db_options, db_path):
+        # get the location of the LOG file and the frequency at which stats are
+        # dumped in the LOG file
+        log_dir_path = None
+        stats_freq_sec = None
+        logs_file_prefix = None
+
+        # fetch frequency at which the stats are dumped in the Rocksdb logs
+        dump_period = 'DBOptions.stats_dump_period_sec'
+        # fetch the directory, if specified, in which the Rocksdb logs are
+        # dumped, by default logs are dumped in same location as database
+        log_dir = 'DBOptions.db_log_dir'
+        log_options = db_options.get_options([dump_period, log_dir])
+        if dump_period in log_options:
+            stats_freq_sec = int(log_options[dump_period][NO_COL_FAMILY])
+        if log_dir in log_options:
+            log_dir_path = log_options[log_dir][NO_COL_FAMILY]
+
+        log_file_name = DBBenchRunner.get_info_log_file_name(
+            log_dir_path, db_path
+        )
+
+        if not log_dir_path:
+            log_dir_path = db_path
+        if not log_dir_path.endswith('/'):
+            log_dir_path += '/'
+
+        logs_file_prefix = log_dir_path + log_file_name
+        return (logs_file_prefix, stats_freq_sec)
+
+    def _get_options_command_line_args_str(self, curr_options):
+        '''
+        This method uses the provided Rocksdb OPTIONS to create a string of
+        command-line arguments for db_bench.
+        The --options_file argument is always given and the options that are
+        not supported by the OPTIONS file are given as separate arguments.
+        '''
+        optional_args_str = DBBenchRunner.get_opt_args_str(
+            curr_options.get_misc_options()
+        )
+        # generate an options configuration file
+        options_file = curr_options.generate_options_config(nonce='12345')
+        optional_args_str += " --options_file=" + options_file
+        return optional_args_str
+
+    def _setup_db_before_experiment(self, curr_options, db_path):
+        # remove destination directory if it already exists
+        try:
+            shutil.rmtree(db_path, ignore_errors=True)
+        except OSError as e:
+            print('Error: rmdir ' + e.filename + ' ' + e.strerror)
+        # setup database with a million keys using the fillrandom benchmark
+        command = "%s --benchmarks=fillrandom --db=%s --num=1000000" % (
+            self.db_bench_binary, db_path
+        )
+        args_str = self._get_options_command_line_args_str(curr_options)
+        command += args_str
+        self._run_command(command)
+
+    def _build_experiment_command(self, curr_options, db_path):
+        command = "%s --benchmarks=%s --statistics --perf_level=3 --db=%s" % (
+            self.db_bench_binary, self.benchmark, db_path
+        )
+        # fetch the command-line arguments string for providing Rocksdb options
+        args_str = self._get_options_command_line_args_str(curr_options)
+        # handle the command-line args passed in the constructor, these
+        # arguments are specific to db_bench
+        for cmd_line_arg in self.db_bench_args:
+            args_str += (" --" + cmd_line_arg)
+        command += args_str
+        return command
+
+    def _run_command(self, command):
+        out_file = open(self.OUTPUT_FILE, "w+")
+        err_file = open(self.ERROR_FILE, "w+")
+        print('executing... - ' + command)
+        subprocess.call(command, shell=True, stdout=out_file, stderr=err_file)
+        out_file.close()
+        err_file.close()
+
+    def run_experiment(self, db_options, db_path):
+        # setup the Rocksdb database before running experiment
+        self._setup_db_before_experiment(db_options, db_path)
+        # get the command to run the experiment
+        command = self._build_experiment_command(db_options, db_path)
+        experiment_start_time = int(time.time())
+        # run experiment
+        self._run_command(command)
+        experiment_end_time = int(time.time())
+        # parse the db_bench experiment output
+        parsed_output = self._parse_output(get_perf_context=True)
+
+        # get the log files path prefix and frequency at which Rocksdb stats
+        # are dumped in the logs
+        logs_file_prefix, stats_freq_sec = self.get_log_options(
+            db_options, parsed_output[self.DB_PATH]
+        )
+        # create the Rocksbd LOGS object
+        db_logs = DatabaseLogs(
+            logs_file_prefix, db_options.get_column_families()
+        )
+        # Create the Log STATS object
+        db_log_stats = LogStatsParser(logs_file_prefix, stats_freq_sec)
+        # Create the PerfContext STATS object
+        db_perf_context = DatabasePerfContext(
+            parsed_output[self.PERF_CON], 0, False
+        )
+        # create the data-sources dictionary
+        data_sources = {
+            DataSource.Type.DB_OPTIONS: [db_options],
+            DataSource.Type.LOG: [db_logs],
+            DataSource.Type.TIME_SERIES: [db_log_stats, db_perf_context]
+        }
+        # Create the ODS STATS object
+        if self.ods_args:
+            key_prefix = ''
+            if 'key_prefix' in self.ods_args:
+                key_prefix = self.ods_args['key_prefix']
+            data_sources[DataSource.Type.TIME_SERIES].append(OdsStatsFetcher(
+                self.ods_args['client_script'],
+                self.ods_args['entity'],
+                experiment_start_time,
+                experiment_end_time,
+                key_prefix
+            ))
+        # return the experiment's data-sources and throughput
+        return data_sources, parsed_output[self.THROUGHPUT]
diff --git a/src/rocksdb/tools/advisor/advisor/db_config_optimizer.py b/src/rocksdb/tools/advisor/advisor/db_config_optimizer.py
new file mode 100644
index 00000000..508c0f8f
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/db_config_optimizer.py
@@ -0,0 +1,282 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from advisor.db_log_parser import NO_COL_FAMILY
+from advisor.db_options_parser import DatabaseOptions
+from advisor.rule_parser import Suggestion
+import copy
+import random
+
+
+class ConfigOptimizer:
+    SCOPE = 'scope'
+    SUGG_VAL = 'suggested values'
+
+    @staticmethod
+    def apply_action_on_value(old_value, action, suggested_values):
+        chosen_sugg_val = None
+        if suggested_values:
+            chosen_sugg_val = random.choice(list(suggested_values))
+        new_value = None
+        if action is Suggestion.Action.set or not old_value:
+            assert(chosen_sugg_val)
+            new_value = chosen_sugg_val
+        else:
+            # For increase/decrease actions, currently the code tries to make
+            # a 30% change in the option's value per iteration. An addend is
+            # also present (+1 or -1) to handle the cases when the option's
+            # old value was 0 or the final int() conversion suppressed the 30%
+            # change made to the option
+            old_value = float(old_value)
+            mul = 0
+            add = 0
+            if action is Suggestion.Action.increase:
+                if old_value < 0:
+                    mul = 0.7
+                    add = 2
+                else:
+                    mul = 1.3
+                    add = 2
+            elif action is Suggestion.Action.decrease:
+                if old_value < 0:
+                    mul = 1.3
+                    add = -2
+                else:
+                    mul = 0.7
+                    add = -2
+            new_value = int(old_value * mul + add)
+        return new_value
+
+    @staticmethod
+    def improve_db_config(options, rule, suggestions_dict):
+        # this method takes ONE 'rule' and applies all its suggestions on the
+        # appropriate options
+        required_options = []
+        rule_suggestions = []
+        for sugg_name in rule.get_suggestions():
+            option = suggestions_dict[sugg_name].option
+            action = suggestions_dict[sugg_name].action
+            # A Suggestion in the rules spec must have the 'option' and
+            # 'action' fields defined, always call perform_checks() method
+            # after parsing the rules file using RulesSpec
+            assert(option)
+            assert(action)
+            required_options.append(option)
+            rule_suggestions.append(suggestions_dict[sugg_name])
+        current_config = options.get_options(required_options)
+        # Create the updated configuration from the rule's suggestions
+        updated_config = {}
+        for sugg in rule_suggestions:
+            # case: when the option is not present in the current configuration
+            if sugg.option not in current_config:
+                try:
+                    new_value = ConfigOptimizer.apply_action_on_value(
+                        None, sugg.action, sugg.suggested_values
+                    )
+                    if sugg.option not in updated_config:
+                        updated_config[sugg.option] = {}
+                    if DatabaseOptions.is_misc_option(sugg.option):
+                        # this suggestion is on an option that is not yet
+                        # supported by the Rocksdb OPTIONS file and so it is
+                        # not prefixed by a section type.
+                        updated_config[sugg.option][NO_COL_FAMILY] = new_value
+                    else:
+                        for col_fam in rule.get_trigger_column_families():
+                            updated_config[sugg.option][col_fam] = new_value
+                except AssertionError:
+                    print(
+                        'WARNING(ConfigOptimizer): provide suggested_values ' +
+                        'for ' + sugg.option
+                    )
+                continue
+            # case: when the option is present in the current configuration
+            if NO_COL_FAMILY in current_config[sugg.option]:
+                old_value = current_config[sugg.option][NO_COL_FAMILY]
+                try:
+                    new_value = ConfigOptimizer.apply_action_on_value(
+                        old_value, sugg.action, sugg.suggested_values
+                    )
+                    if sugg.option not in updated_config:
+                        updated_config[sugg.option] = {}
+                    updated_config[sugg.option][NO_COL_FAMILY] = new_value
+                except AssertionError:
+                    print(
+                        'WARNING(ConfigOptimizer): provide suggested_values ' +
+                        'for ' + sugg.option
+                    )
+            else:
+                for col_fam in rule.get_trigger_column_families():
+                    old_value = None
+                    if col_fam in current_config[sugg.option]:
+                        old_value = current_config[sugg.option][col_fam]
+                    try:
+                        new_value = ConfigOptimizer.apply_action_on_value(
+                            old_value, sugg.action, sugg.suggested_values
+                        )
+                        if sugg.option not in updated_config:
+                            updated_config[sugg.option] = {}
+                        updated_config[sugg.option][col_fam] = new_value
+                    except AssertionError:
+                        print(
+                            'WARNING(ConfigOptimizer): provide ' +
+                            'suggested_values for ' + sugg.option
+                        )
+        return current_config, updated_config
+
+    @staticmethod
+    def pick_rule_to_apply(rules, last_rule_name, rules_tried, backtrack):
+        if not rules:
+            print('\nNo more rules triggered!')
+            return None
+        # if the last rule provided an improvement in the database performance,
+        # and it was triggered again (i.e. it is present in 'rules'), then pick
+        # the same rule for this iteration too.
+        if last_rule_name and not backtrack:
+            for rule in rules:
+                if rule.name == last_rule_name:
+                    return rule
+        # there was no previous rule OR the previous rule did not improve db
+        # performance OR it was not triggered for this iteration,
+        # then pick another rule that has not been tried yet
+        for rule in rules:
+            if rule.name not in rules_tried:
+                return rule
+        print('\nAll rules have been exhausted')
+        return None
+
+    @staticmethod
+    def apply_suggestions(
+        triggered_rules,
+        current_rule_name,
+        rules_tried,
+        backtrack,
+        curr_options,
+        suggestions_dict
+    ):
+        curr_rule = ConfigOptimizer.pick_rule_to_apply(
+            triggered_rules, current_rule_name, rules_tried, backtrack
+        )
+        if not curr_rule:
+            return tuple([None]*4)
+        # if a rule has been picked for improving db_config, update rules_tried
+        rules_tried.add(curr_rule.name)
+        # get updated config based on the picked rule
+        curr_conf, updated_conf = ConfigOptimizer.improve_db_config(
+            curr_options, curr_rule, suggestions_dict
+        )
+        conf_diff = DatabaseOptions.get_options_diff(curr_conf, updated_conf)
+        if not conf_diff:  # the current and updated configs are the same
+            curr_rule, rules_tried, curr_conf, updated_conf = (
+                ConfigOptimizer.apply_suggestions(
+                    triggered_rules,
+                    None,
+                    rules_tried,
+                    backtrack,
+                    curr_options,
+                    suggestions_dict
+                )
+            )
+        print('returning from apply_suggestions')
+        return (curr_rule, rules_tried, curr_conf, updated_conf)
+
+    # TODO(poojam23): check if this method is required or can we directly set
+    # the config equal to the curr_config
+    @staticmethod
+    def get_backtrack_config(curr_config, updated_config):
+        diff = DatabaseOptions.get_options_diff(curr_config, updated_config)
+        bt_config = {}
+        for option in diff:
+            bt_config[option] = {}
+            for col_fam in diff[option]:
+                bt_config[option][col_fam] = diff[option][col_fam][0]
+        print(bt_config)
+        return bt_config
+
+    def __init__(self, bench_runner, db_options, rule_parser, base_db):
+        self.bench_runner = bench_runner
+        self.db_options = db_options
+        self.rule_parser = rule_parser
+        self.base_db_path = base_db
+
+    def run(self):
+        # In every iteration of this method's optimization loop we pick ONE
+        # RULE from all the triggered rules and apply all its suggestions to
+        # the appropriate options.
+        # bootstrapping the optimizer
+        print('Bootstrapping optimizer:')
+        options = copy.deepcopy(self.db_options)
+        old_data_sources, old_metric = (
+            self.bench_runner.run_experiment(options, self.base_db_path)
+        )
+        print('Initial metric: ' + str(old_metric))
+        self.rule_parser.load_rules_from_spec()
+        self.rule_parser.perform_section_checks()
+        triggered_rules = self.rule_parser.get_triggered_rules(
+            old_data_sources, options.get_column_families()
+        )
+        print('\nTriggered:')
+        self.rule_parser.print_rules(triggered_rules)
+        backtrack = False
+        rules_tried = set()
+        curr_rule, rules_tried, curr_conf, updated_conf = (
+            ConfigOptimizer.apply_suggestions(
+                triggered_rules,
+                None,
+                rules_tried,
+                backtrack,
+                options,
+                self.rule_parser.get_suggestions_dict()
+            )
+        )
+        # the optimizer loop
+        while curr_rule:
+            print('\nRule picked for next iteration:')
+            print(curr_rule.name)
+            print('\ncurrent config:')
+            print(curr_conf)
+            print('updated config:')
+            print(updated_conf)
+            options.update_options(updated_conf)
+            # run bench_runner with updated config
+            new_data_sources, new_metric = (
+                self.bench_runner.run_experiment(options, self.base_db_path)
+            )
+            print('\nnew metric: ' + str(new_metric))
+            backtrack = not self.bench_runner.is_metric_better(
+                new_metric, old_metric
+            )
+            # update triggered_rules, metric, data_sources, if required
+            if backtrack:
+                # revert changes to options config
+                print('\nBacktracking to previous configuration')
+                backtrack_conf = ConfigOptimizer.get_backtrack_config(
+                    curr_conf, updated_conf
+                )
+                options.update_options(backtrack_conf)
+            else:
+                # run advisor on new data sources
+                self.rule_parser.load_rules_from_spec()  # reboot the advisor
+                self.rule_parser.perform_section_checks()
+                triggered_rules = self.rule_parser.get_triggered_rules(
+                    new_data_sources, options.get_column_families()
+                )
+                print('\nTriggered:')
+                self.rule_parser.print_rules(triggered_rules)
+                old_metric = new_metric
+                old_data_sources = new_data_sources
+                rules_tried = set()
+            # pick rule to work on and set curr_rule to that
+            curr_rule, rules_tried, curr_conf, updated_conf = (
+                ConfigOptimizer.apply_suggestions(
+                    triggered_rules,
+                    curr_rule.name,
+                    rules_tried,
+                    backtrack,
+                    options,
+                    self.rule_parser.get_suggestions_dict()
+                )
+            )
+        # return the final database options configuration
+        return options
diff --git a/src/rocksdb/tools/advisor/advisor/db_log_parser.py b/src/rocksdb/tools/advisor/advisor/db_log_parser.py
new file mode 100644
index 00000000..efd41a81
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/db_log_parser.py
@@ -0,0 +1,131 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from abc import ABC, abstractmethod
+from calendar import timegm
+from enum import Enum
+import glob
+import re
+import time
+
+
+NO_COL_FAMILY = 'DB_WIDE'
+
+
+class DataSource(ABC):
+    class Type(Enum):
+        LOG = 1
+        DB_OPTIONS = 2
+        TIME_SERIES = 3
+
+    def __init__(self, type):
+        self.type = type
+
+    @abstractmethod
+    def check_and_trigger_conditions(self, conditions):
+        pass
+
+
+class Log:
+    @staticmethod
+    def is_new_log(log_line):
+        # The assumption is that a new log will start with a date printed in
+        # the below regex format.
+        date_regex = '\d{4}/\d{2}/\d{2}-\d{2}:\d{2}:\d{2}\.\d{6}'
+        return re.match(date_regex, log_line)
+
+    def __init__(self, log_line, column_families):
+        token_list = log_line.strip().split()
+        self.time = token_list[0]
+        self.context = token_list[1]
+        self.message = " ".join(token_list[2:])
+        self.column_family = None
+        # example log for 'default' column family:
+        # "2018/07/25-17:29:05.176080 7f969de68700 [db/compaction_job.cc:1634]
+        # [default] [JOB 3] Compacting 24@0 + 16@1 files to L1, score 6.00\n"
+        for col_fam in column_families:
+            search_for_str = '\[' + col_fam + '\]'
+            if re.search(search_for_str, self.message):
+                self.column_family = col_fam
+                break
+        if not self.column_family:
+            self.column_family = NO_COL_FAMILY
+
+    def get_human_readable_time(self):
+        # example from a log line: '2018/07/25-11:25:45.782710'
+        return self.time
+
+    def get_column_family(self):
+        return self.column_family
+
+    def get_context(self):
+        return self.context
+
+    def get_message(self):
+        return self.message
+
+    def append_message(self, remaining_log):
+        self.message = self.message + '\n' + remaining_log.strip()
+
+    def get_timestamp(self):
+        # example: '2018/07/25-11:25:45.782710' will be converted to the GMT
+        # Unix timestamp 1532517945 (note: this method assumes that self.time
+        # is in GMT)
+        hr_time = self.time + 'GMT'
+        timestamp = timegm(time.strptime(hr_time, "%Y/%m/%d-%H:%M:%S.%f%Z"))
+        return timestamp
+
+    def __repr__(self):
+        return (
+            'time: ' + self.time + '; context: ' + self.context +
+            '; col_fam: ' + self.column_family +
+            '; message: ' + self.message
+        )
+
+
+class DatabaseLogs(DataSource):
+    def __init__(self, logs_path_prefix, column_families):
+        super().__init__(DataSource.Type.LOG)
+        self.logs_path_prefix = logs_path_prefix
+        self.column_families = column_families
+
+    def trigger_conditions_for_log(self, conditions, log):
+        # For a LogCondition object, trigger is:
+        # Dict[column_family_name, List[Log]]. This explains why the condition
+        # was triggered and for which column families.
+        for cond in conditions:
+            if re.search(cond.regex, log.get_message(), re.IGNORECASE):
+                trigger = cond.get_trigger()
+                if not trigger:
+                    trigger = {}
+                if log.get_column_family() not in trigger:
+                    trigger[log.get_column_family()] = []
+                trigger[log.get_column_family()].append(log)
+                cond.set_trigger(trigger)
+
+    def check_and_trigger_conditions(self, conditions):
+        for file_name in glob.glob(self.logs_path_prefix + '*'):
+            # TODO(poojam23): find a way to distinguish between log files
+            # - generated in the current experiment but are labeled 'old'
+            # because they LOGs exceeded the file size limit  AND
+            # - generated in some previous experiment that are also labeled
+            # 'old' and were not deleted for some reason
+            if re.search('old', file_name, re.IGNORECASE):
+                continue
+            with open(file_name, 'r') as db_logs:
+                new_log = None
+                for line in db_logs:
+                    if Log.is_new_log(line):
+                        if new_log:
+                            self.trigger_conditions_for_log(
+                                conditions, new_log
+                            )
+                        new_log = Log(line, self.column_families)
+                    else:
+                        # To account for logs split into multiple lines
+                        new_log.append_message(line)
+            # Check for the last log in the file.
+            if new_log:
+                self.trigger_conditions_for_log(conditions, new_log)
diff --git a/src/rocksdb/tools/advisor/advisor/db_options_parser.py b/src/rocksdb/tools/advisor/advisor/db_options_parser.py
new file mode 100644
index 00000000..e689d892
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/db_options_parser.py
@@ -0,0 +1,358 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+import copy
+from advisor.db_log_parser import DataSource, NO_COL_FAMILY
+from advisor.ini_parser import IniParser
+import os
+
+
+class OptionsSpecParser(IniParser):
+    @staticmethod
+    def is_new_option(line):
+        return '=' in line
+
+    @staticmethod
+    def get_section_type(line):
+        '''
+        Example section header: [TableOptions/BlockBasedTable "default"]
+        Here ConfigurationOptimizer returned would be
+        'TableOptions.BlockBasedTable'
+        '''
+        section_path = line.strip()[1:-1].split()[0]
+        section_type = '.'.join(section_path.split('/'))
+        return section_type
+
+    @staticmethod
+    def get_section_name(line):
+        # example: get_section_name('[CFOptions "default"]')
+        token_list = line.strip()[1:-1].split('"')
+        # token_list = ['CFOptions', 'default', '']
+        if len(token_list) < 3:
+            return None
+        return token_list[1]  # return 'default'
+
+    @staticmethod
+    def get_section_str(section_type, section_name):
+        # Example:
+        # Case 1: get_section_str('DBOptions', NO_COL_FAMILY)
+        # Case 2: get_section_str('TableOptions.BlockBasedTable', 'default')
+        section_type = '/'.join(section_type.strip().split('.'))
+        # Case 1: section_type = 'DBOptions'
+        # Case 2: section_type = 'TableOptions/BlockBasedTable'
+        section_str = '[' + section_type
+        if section_name == NO_COL_FAMILY:
+            # Case 1: '[DBOptions]'
+            return (section_str + ']')
+        else:
+            # Case 2: '[TableOptions/BlockBasedTable "default"]'
+            return section_str + ' "' + section_name + '"]'
+
+    @staticmethod
+    def get_option_str(key, values):
+        option_str = key + '='
+        # get_option_str('db_log_dir', None), returns 'db_log_dir='
+        if values:
+            # example:
+            # get_option_str('max_bytes_for_level_multiplier_additional',
+            # [1,1,1,1,1,1,1]), returned string:
+            # 'max_bytes_for_level_multiplier_additional=1:1:1:1:1:1:1'
+            if isinstance(values, list):
+                for value in values:
+                    option_str += (str(value) + ':')
+                option_str = option_str[:-1]
+            else:
+                # example: get_option_str('write_buffer_size', 1048576)
+                # returned string: 'write_buffer_size=1048576'
+                option_str += str(values)
+        return option_str
+
+
+class DatabaseOptions(DataSource):
+
+    @staticmethod
+    def is_misc_option(option_name):
+        # these are miscellaneous options that are not yet supported by the
+        # Rocksdb options file, hence they are not prefixed with any section
+        # name
+        return '.' not in option_name
+
+    @staticmethod
+    def get_options_diff(opt_old, opt_new):
+        # type: Dict[option, Dict[col_fam, value]] X 2 ->
+        # Dict[option, Dict[col_fam, Tuple(old_value, new_value)]]
+        # note: diff should contain a tuple of values only if they are
+        # different from each other
+        options_union = set(opt_old.keys()).union(set(opt_new.keys()))
+        diff = {}
+        for opt in options_union:
+            diff[opt] = {}
+            # if option in options_union, then it must be in one of the configs
+            if opt not in opt_old:
+                for col_fam in opt_new[opt]:
+                    diff[opt][col_fam] = (None, opt_new[opt][col_fam])
+            elif opt not in opt_new:
+                for col_fam in opt_old[opt]:
+                    diff[opt][col_fam] = (opt_old[opt][col_fam], None)
+            else:
+                for col_fam in opt_old[opt]:
+                    if col_fam in opt_new[opt]:
+                        if opt_old[opt][col_fam] != opt_new[opt][col_fam]:
+                            diff[opt][col_fam] = (
+                                opt_old[opt][col_fam],
+                                opt_new[opt][col_fam]
+                            )
+                    else:
+                        diff[opt][col_fam] = (opt_old[opt][col_fam], None)
+                for col_fam in opt_new[opt]:
+                    if col_fam in opt_old[opt]:
+                        if opt_old[opt][col_fam] != opt_new[opt][col_fam]:
+                            diff[opt][col_fam] = (
+                                opt_old[opt][col_fam],
+                                opt_new[opt][col_fam]
+                            )
+                    else:
+                        diff[opt][col_fam] = (None, opt_new[opt][col_fam])
+            if not diff[opt]:
+                diff.pop(opt)
+        return diff
+
+    def __init__(self, rocksdb_options, misc_options=None):
+        super().__init__(DataSource.Type.DB_OPTIONS)
+        # The options are stored in the following data structure:
+        # Dict[section_type, Dict[section_name, Dict[option_name, value]]]
+        self.options_dict = None
+        self.column_families = None
+        # Load the options from the given file to a dictionary.
+        self.load_from_source(rocksdb_options)
+        # Setup the miscellaneous options expected to be List[str], where each
+        # element in the List has the format "<option_name>=<option_value>"
+        # These options are the ones that are not yet supported by the Rocksdb
+        # OPTIONS file, so they are provided separately
+        self.setup_misc_options(misc_options)
+
+    def setup_misc_options(self, misc_options):
+        self.misc_options = {}
+        if misc_options:
+            for option_pair_str in misc_options:
+                option_name = option_pair_str.split('=')[0].strip()
+                option_value = option_pair_str.split('=')[1].strip()
+                self.misc_options[option_name] = option_value
+
+    def load_from_source(self, options_path):
+        self.options_dict = {}
+        with open(options_path, 'r') as db_options:
+            for line in db_options:
+                line = OptionsSpecParser.remove_trailing_comment(line)
+                if not line:
+                    continue
+                if OptionsSpecParser.is_section_header(line):
+                    curr_sec_type = (
+                        OptionsSpecParser.get_section_type(line)
+                    )
+                    curr_sec_name = OptionsSpecParser.get_section_name(line)
+                    if curr_sec_type not in self.options_dict:
+                        self.options_dict[curr_sec_type] = {}
+                    if not curr_sec_name:
+                        curr_sec_name = NO_COL_FAMILY
+                    self.options_dict[curr_sec_type][curr_sec_name] = {}
+                    # example: if the line read from the Rocksdb OPTIONS file
+                    # is [CFOptions "default"], then the section type is
+                    # CFOptions and 'default' is the name of a column family
+                    # that for this database, so it's added to the list of
+                    # column families stored in this object
+                    if curr_sec_type == 'CFOptions':
+                        if not self.column_families:
+                            self.column_families = []
+                        self.column_families.append(curr_sec_name)
+                elif OptionsSpecParser.is_new_option(line):
+                    key, value = OptionsSpecParser.get_key_value_pair(line)
+                    self.options_dict[curr_sec_type][curr_sec_name][key] = (
+                        value
+                    )
+                else:
+                    error = 'Not able to parse line in Options file.'
+                    OptionsSpecParser.exit_with_parse_error(line, error)
+
+    def get_misc_options(self):
+        # these are options that are not yet supported by the Rocksdb OPTIONS
+        # file, hence they are provided and stored separately
+        return self.misc_options
+
+    def get_column_families(self):
+        return self.column_families
+
+    def get_all_options(self):
+        # This method returns all the options that are stored in this object as
+        # a: Dict[<sec_type>.<option_name>: Dict[col_fam, option_value]]
+        all_options = []
+        # Example: in the section header '[CFOptions "default"]' read from the
+        # OPTIONS file, sec_type='CFOptions'
+        for sec_type in self.options_dict:
+            for col_fam in self.options_dict[sec_type]:
+                for opt_name in self.options_dict[sec_type][col_fam]:
+                    option = sec_type + '.' + opt_name
+                    all_options.append(option)
+        all_options.extend(list(self.misc_options.keys()))
+        return self.get_options(all_options)
+
+    def get_options(self, reqd_options):
+        # type: List[str] -> Dict[str, Dict[str, Any]]
+        # List[option] -> Dict[option, Dict[col_fam, value]]
+        reqd_options_dict = {}
+        for option in reqd_options:
+            if DatabaseOptions.is_misc_option(option):
+                # the option is not prefixed by '<section_type>.' because it is
+                # not yet supported by the Rocksdb OPTIONS file; so it has to
+                # be fetched from the misc_options dictionary
+                if option not in self.misc_options:
+                    continue
+                if option not in reqd_options_dict:
+                    reqd_options_dict[option] = {}
+                reqd_options_dict[option][NO_COL_FAMILY] = (
+                    self.misc_options[option]
+                )
+            else:
+                # Example: option = 'TableOptions.BlockBasedTable.block_align'
+                # then, sec_type = 'TableOptions.BlockBasedTable'
+                sec_type = '.'.join(option.split('.')[:-1])
+                # opt_name = 'block_align'
+                opt_name = option.split('.')[-1]
+                if sec_type not in self.options_dict:
+                    continue
+                for col_fam in self.options_dict[sec_type]:
+                    if opt_name in self.options_dict[sec_type][col_fam]:
+                        if option not in reqd_options_dict:
+                            reqd_options_dict[option] = {}
+                        reqd_options_dict[option][col_fam] = (
+                            self.options_dict[sec_type][col_fam][opt_name]
+                        )
+        return reqd_options_dict
+
+    def update_options(self, options):
+        # An example 'options' object looks like:
+        # {'DBOptions.max_background_jobs': {NO_COL_FAMILY: 2},
+        # 'CFOptions.write_buffer_size': {'default': 1048576, 'cf_A': 128000},
+        # 'bloom_bits': {NO_COL_FAMILY: 4}}
+        for option in options:
+            if DatabaseOptions.is_misc_option(option):
+                # this is a misc_option i.e. an option that is not yet
+                # supported by the Rocksdb OPTIONS file, so it is not prefixed
+                # by '<section_type>.' and must be stored in the separate
+                # misc_options dictionary
+                if NO_COL_FAMILY not in options[option]:
+                    print(
+                        'WARNING(DatabaseOptions.update_options): not ' +
+                        'updating option ' + option + ' because it is in ' +
+                        'misc_option format but its scope is not ' +
+                        NO_COL_FAMILY + '. Check format of option.'
+                    )
+                    continue
+                self.misc_options[option] = options[option][NO_COL_FAMILY]
+            else:
+                sec_name = '.'.join(option.split('.')[:-1])
+                opt_name = option.split('.')[-1]
+                if sec_name not in self.options_dict:
+                    self.options_dict[sec_name] = {}
+                for col_fam in options[option]:
+                    # if the option is not already present in the dictionary,
+                    # it will be inserted, else it will be updated to the new
+                    # value
+                    if col_fam not in self.options_dict[sec_name]:
+                        self.options_dict[sec_name][col_fam] = {}
+                    self.options_dict[sec_name][col_fam][opt_name] = (
+                        copy.deepcopy(options[option][col_fam])
+                    )
+
+    def generate_options_config(self, nonce):
+        # this method generates a Rocksdb OPTIONS file in the INI format from
+        # the options stored in self.options_dict
+        this_path = os.path.abspath(os.path.dirname(__file__))
+        file_name = '../temp/OPTIONS_' + str(nonce) + '.tmp'
+        file_path = os.path.join(this_path, file_name)
+        with open(file_path, 'w') as fp:
+            for section in self.options_dict:
+                for col_fam in self.options_dict[section]:
+                    fp.write(
+                        OptionsSpecParser.get_section_str(section, col_fam) +
+                        '\n'
+                    )
+                    for option in self.options_dict[section][col_fam]:
+                        values = self.options_dict[section][col_fam][option]
+                        fp.write(
+                            OptionsSpecParser.get_option_str(option, values) +
+                            '\n'
+                        )
+                fp.write('\n')
+        return file_path
+
+    def check_and_trigger_conditions(self, conditions):
+        for cond in conditions:
+            reqd_options_dict = self.get_options(cond.options)
+            # This contains the indices of options that are specific to some
+            # column family and are not database-wide options.
+            incomplete_option_ix = []
+            options = []
+            missing_reqd_option = False
+            for ix, option in enumerate(cond.options):
+                if option not in reqd_options_dict:
+                    print(
+                        'WARNING(DatabaseOptions.check_and_trigger): ' +
+                        'skipping condition ' + cond.name + ' because it '
+                        'requires option ' + option + ' but this option is' +
+                        ' not available'
+                    )
+                    missing_reqd_option = True
+                    break  # required option is absent
+                if NO_COL_FAMILY in reqd_options_dict[option]:
+                    options.append(reqd_options_dict[option][NO_COL_FAMILY])
+                else:
+                    options.append(None)
+                    incomplete_option_ix.append(ix)
+
+            if missing_reqd_option:
+                continue
+
+            # if all the options are database-wide options
+            if not incomplete_option_ix:
+                try:
+                    if eval(cond.eval_expr):
+                        cond.set_trigger({NO_COL_FAMILY: options})
+                except Exception as e:
+                    print(
+                        'WARNING(DatabaseOptions) check_and_trigger:' + str(e)
+                    )
+                continue
+
+            # for all the options that are not database-wide, we look for their
+            # values specific to column families
+            col_fam_options_dict = {}
+            for col_fam in self.column_families:
+                present = True
+                for ix in incomplete_option_ix:
+                    option = cond.options[ix]
+                    if col_fam not in reqd_options_dict[option]:
+                        present = False
+                        break
+                    options[ix] = reqd_options_dict[option][col_fam]
+                if present:
+                    try:
+                        if eval(cond.eval_expr):
+                            col_fam_options_dict[col_fam] = (
+                                copy.deepcopy(options)
+                            )
+                    except Exception as e:
+                        print(
+                            'WARNING(DatabaseOptions) check_and_trigger: ' +
+                            str(e)
+                        )
+            # Trigger for an OptionCondition object is of the form:
+            # Dict[col_fam_name: List[option_value]]
+            # where col_fam_name is the name of a column family for which
+            # 'eval_expr' evaluated to True and List[option_value] is the list
+            # of values of the options specified in the condition's 'options'
+            # field
+            if col_fam_options_dict:
+                cond.set_trigger(col_fam_options_dict)
diff --git a/src/rocksdb/tools/advisor/advisor/db_stats_fetcher.py b/src/rocksdb/tools/advisor/advisor/db_stats_fetcher.py
new file mode 100755
index 00000000..cf497cf1
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/db_stats_fetcher.py
@@ -0,0 +1,338 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from advisor.db_log_parser import Log
+from advisor.db_timeseries_parser import TimeSeriesData, NO_ENTITY
+import copy
+import glob
+import re
+import subprocess
+import time
+
+
+class LogStatsParser(TimeSeriesData):
+    STATS = 'STATISTICS:'
+
+    @staticmethod
+    def parse_log_line_for_stats(log_line):
+        # Example stat line (from LOG file):
+        # "rocksdb.db.get.micros P50 : 8.4 P95 : 21.8 P99 : 33.9 P100 : 92.0\n"
+        token_list = log_line.strip().split()
+        # token_list = ['rocksdb.db.get.micros', 'P50', ':', '8.4', 'P95', ':',
+        # '21.8', 'P99', ':', '33.9', 'P100', ':', '92.0']
+        stat_prefix = token_list[0] + '.'  # 'rocksdb.db.get.micros.'
+        stat_values = [
+            token
+            for token in token_list[1:]
+            if token != ':'
+        ]
+        # stat_values = ['P50', '8.4', 'P95', '21.8', 'P99', '33.9', 'P100',
+        # '92.0']
+        stat_dict = {}
+        for ix, metric in enumerate(stat_values):
+            if ix % 2 == 0:
+                stat_name = stat_prefix + metric
+                stat_name = stat_name.lower()  # Note: case insensitive names
+            else:
+                stat_dict[stat_name] = float(metric)
+        # stat_dict = {'rocksdb.db.get.micros.p50': 8.4,
+        # 'rocksdb.db.get.micros.p95': 21.8, 'rocksdb.db.get.micros.p99': 33.9,
+        # 'rocksdb.db.get.micros.p100': 92.0}
+        return stat_dict
+
+    def __init__(self, logs_path_prefix, stats_freq_sec):
+        super().__init__()
+        self.logs_file_prefix = logs_path_prefix
+        self.stats_freq_sec = stats_freq_sec
+        self.duration_sec = 60
+
+    def get_keys_from_conditions(self, conditions):
+        # Note: case insensitive stat names
+        reqd_stats = []
+        for cond in conditions:
+            for key in cond.keys:
+                key = key.lower()
+                # some keys are prepended with '[]' for OdsStatsFetcher to
+                # replace this with the appropriate key_prefix, remove these
+                # characters here since the LogStatsParser does not need
+                # a prefix
+                if key.startswith('[]'):
+                    reqd_stats.append(key[2:])
+                else:
+                    reqd_stats.append(key)
+        return reqd_stats
+
+    def add_to_timeseries(self, log, reqd_stats):
+        # this method takes in the Log object that contains the Rocksdb stats
+        # and a list of required stats, then it parses the stats line by line
+        # to fetch required stats and add them to the keys_ts object
+        # Example: reqd_stats = ['rocksdb.block.cache.hit.count',
+        # 'rocksdb.db.get.micros.p99']
+        # Let log.get_message() returns following string:
+        # "[WARN] [db/db_impl.cc:485] STATISTICS:\n
+        # rocksdb.block.cache.miss COUNT : 1459\n
+        # rocksdb.block.cache.hit COUNT : 37\n
+        # ...
+        # rocksdb.db.get.micros P50 : 15.6 P95 : 39.7 P99 : 62.6 P100 : 148.0\n
+        # ..."
+        new_lines = log.get_message().split('\n')
+        # let log_ts = 1532518219
+        log_ts = log.get_timestamp()
+        # example updates to keys_ts:
+        # keys_ts[NO_ENTITY]['rocksdb.db.get.micros.p99'][1532518219] = 62.6
+        # keys_ts[NO_ENTITY]['rocksdb.block.cache.hit.count'][1532518219] = 37
+        for line in new_lines[1:]:  # new_lines[0] does not contain any stats
+            stats_on_line = self.parse_log_line_for_stats(line)
+            for stat in stats_on_line:
+                if stat in reqd_stats:
+                    if stat not in self.keys_ts[NO_ENTITY]:
+                        self.keys_ts[NO_ENTITY][stat] = {}
+                    self.keys_ts[NO_ENTITY][stat][log_ts] = stats_on_line[stat]
+
+    def fetch_timeseries(self, reqd_stats):
+        # this method parses the Rocksdb LOG file and generates timeseries for
+        # each of the statistic in the list reqd_stats
+        self.keys_ts = {NO_ENTITY: {}}
+        for file_name in glob.glob(self.logs_file_prefix + '*'):
+            # TODO(poojam23): find a way to distinguish between 'old' log files
+            # from current and previous experiments, present in the same
+            # directory
+            if re.search('old', file_name, re.IGNORECASE):
+                continue
+            with open(file_name, 'r') as db_logs:
+                new_log = None
+                for line in db_logs:
+                    if Log.is_new_log(line):
+                        if (
+                            new_log and
+                            re.search(self.STATS, new_log.get_message())
+                        ):
+                            self.add_to_timeseries(new_log, reqd_stats)
+                        new_log = Log(line, column_families=[])
+                    else:
+                        # To account for logs split into multiple lines
+                        new_log.append_message(line)
+            # Check for the last log in the file.
+            if new_log and re.search(self.STATS, new_log.get_message()):
+                self.add_to_timeseries(new_log, reqd_stats)
+
+
+class DatabasePerfContext(TimeSeriesData):
+    # TODO(poojam23): check if any benchrunner provides PerfContext sampled at
+    # regular intervals
+    def __init__(self, perf_context_ts, stats_freq_sec, cumulative):
+        '''
+        perf_context_ts is expected to be in the following format:
+        Dict[metric, Dict[timestamp, value]], where for
+        each (metric, timestamp) pair, the value is database-wide (i.e.
+        summed over all the threads involved)
+        if stats_freq_sec == 0, per-metric only one value is reported
+        '''
+        super().__init__()
+        self.stats_freq_sec = stats_freq_sec
+        self.keys_ts = {NO_ENTITY: perf_context_ts}
+        if cumulative:
+            self.unaccumulate_metrics()
+
+    def unaccumulate_metrics(self):
+        # if the perf context metrics provided are cumulative in nature, this
+        # method can be used to convert them to a disjoint format
+        epoch_ts = copy.deepcopy(self.keys_ts)
+        for stat in self.keys_ts[NO_ENTITY]:
+            timeseries = sorted(
+                list(self.keys_ts[NO_ENTITY][stat].keys()), reverse=True
+            )
+            if len(timeseries) < 2:
+                continue
+            for ix, ts in enumerate(timeseries[:-1]):
+                epoch_ts[NO_ENTITY][stat][ts] = (
+                    epoch_ts[NO_ENTITY][stat][ts] -
+                    epoch_ts[NO_ENTITY][stat][timeseries[ix+1]]
+                )
+                if epoch_ts[NO_ENTITY][stat][ts] < 0:
+                    raise ValueError('DBPerfContext: really cumulative?')
+            # drop the smallest timestamp in the timeseries for this metric
+            epoch_ts[NO_ENTITY][stat].pop(timeseries[-1])
+        self.keys_ts = epoch_ts
+
+    def get_keys_from_conditions(self, conditions):
+        reqd_stats = []
+        for cond in conditions:
+            reqd_stats.extend([key.lower() for key in cond.keys])
+        return reqd_stats
+
+    def fetch_timeseries(self, statistics):
+        # this method is redundant for DatabasePerfContext because the __init__
+        # does the job of populating 'keys_ts'
+        pass
+
+
+class OdsStatsFetcher(TimeSeriesData):
+    # class constants
+    OUTPUT_FILE = 'temp/stats_out.tmp'
+    ERROR_FILE = 'temp/stats_err.tmp'
+    RAPIDO_COMMAND = "%s --entity=%s --key=%s --tstart=%s --tend=%s --showtime"
+
+    # static methods
+    @staticmethod
+    def _get_string_in_quotes(value):
+        return '"' + str(value) + '"'
+
+    @staticmethod
+    def _get_time_value_pair(pair_string):
+        # example pair_string: '[1532544591, 97.3653601828]'
+        pair_string = pair_string.replace('[', '')
+        pair_string = pair_string.replace(']', '')
+        pair = pair_string.split(',')
+        first = int(pair[0].strip())
+        second = float(pair[1].strip())
+        return [first, second]
+
+    @staticmethod
+    def _get_ods_cli_stime(start_time):
+        diff = int(time.time() - int(start_time))
+        stime = str(diff) + '_s'
+        return stime
+
+    def __init__(
+        self, client, entities, start_time, end_time, key_prefix=None
+    ):
+        super().__init__()
+        self.client = client
+        self.entities = entities
+        self.start_time = start_time
+        self.end_time = end_time
+        self.key_prefix = key_prefix
+        self.stats_freq_sec = 60
+        self.duration_sec = 60
+
+    def execute_script(self, command):
+        print('executing...')
+        print(command)
+        out_file = open(self.OUTPUT_FILE, "w+")
+        err_file = open(self.ERROR_FILE, "w+")
+        subprocess.call(command, shell=True, stdout=out_file, stderr=err_file)
+        out_file.close()
+        err_file.close()
+
+    def parse_rapido_output(self):
+        # Output looks like the following:
+        # <entity_name>\t<key_name>\t[[ts, value], [ts, value], ...]
+        # ts = timestamp; value = value of key_name in entity_name at time ts
+        self.keys_ts = {}
+        with open(self.OUTPUT_FILE, 'r') as fp:
+            for line in fp:
+                token_list = line.strip().split('\t')
+                entity = token_list[0]
+                key = token_list[1]
+                if entity not in self.keys_ts:
+                    self.keys_ts[entity] = {}
+                if key not in self.keys_ts[entity]:
+                    self.keys_ts[entity][key] = {}
+                list_of_lists = [
+                    self._get_time_value_pair(pair_string)
+                    for pair_string in token_list[2].split('],')
+                ]
+                value = {pair[0]: pair[1] for pair in list_of_lists}
+                self.keys_ts[entity][key] = value
+
+    def parse_ods_output(self):
+        # Output looks like the following:
+        # <entity_name>\t<key_name>\t<timestamp>\t<value>
+        # there is one line per (entity_name, key_name, timestamp)
+        self.keys_ts = {}
+        with open(self.OUTPUT_FILE, 'r') as fp:
+            for line in fp:
+                token_list = line.split()
+                entity = token_list[0]
+                if entity not in self.keys_ts:
+                    self.keys_ts[entity] = {}
+                key = token_list[1]
+                if key not in self.keys_ts[entity]:
+                    self.keys_ts[entity][key] = {}
+                self.keys_ts[entity][key][token_list[2]] = token_list[3]
+
+    def fetch_timeseries(self, statistics):
+        # this method fetches the timeseries of required stats from the ODS
+        # service and populates the 'keys_ts' object appropriately
+        print('OdsStatsFetcher: fetching ' + str(statistics))
+        if re.search('rapido', self.client, re.IGNORECASE):
+            command = self.RAPIDO_COMMAND % (
+                self.client,
+                self._get_string_in_quotes(self.entities),
+                self._get_string_in_quotes(','.join(statistics)),
+                self._get_string_in_quotes(self.start_time),
+                self._get_string_in_quotes(self.end_time)
+            )
+            # Run the tool and fetch the time-series data
+            self.execute_script(command)
+            # Parse output and populate the 'keys_ts' map
+            self.parse_rapido_output()
+        elif re.search('ods', self.client, re.IGNORECASE):
+            command = (
+                self.client + ' ' +
+                '--stime=' + self._get_ods_cli_stime(self.start_time) + ' ' +
+                self._get_string_in_quotes(self.entities) + ' ' +
+                self._get_string_in_quotes(','.join(statistics))
+            )
+            # Run the tool and fetch the time-series data
+            self.execute_script(command)
+            # Parse output and populate the 'keys_ts' map
+            self.parse_ods_output()
+
+    def get_keys_from_conditions(self, conditions):
+        reqd_stats = []
+        for cond in conditions:
+            for key in cond.keys:
+                use_prefix = False
+                if key.startswith('[]'):
+                    use_prefix = True
+                    key = key[2:]
+                # TODO(poojam23): this is very hacky and needs to be improved
+                if key.startswith("rocksdb"):
+                    key += ".60"
+                if use_prefix:
+                    if not self.key_prefix:
+                        print('Warning: OdsStatsFetcher might need key prefix')
+                        print('for the key: ' + key)
+                    else:
+                        key = self.key_prefix + "." + key
+                reqd_stats.append(key)
+        return reqd_stats
+
+    def fetch_rate_url(self, entities, keys, window_len, percent, display):
+        # type: (List[str], List[str], str, str, bool) -> str
+        transform_desc = (
+            "rate(" + str(window_len) + ",duration=" + str(self.duration_sec)
+        )
+        if percent:
+            transform_desc = transform_desc + ",%)"
+        else:
+            transform_desc = transform_desc + ")"
+        if re.search('rapido', self.client, re.IGNORECASE):
+            command = self.RAPIDO_COMMAND + " --transform=%s --url=%s"
+            command = command % (
+                self.client,
+                self._get_string_in_quotes(','.join(entities)),
+                self._get_string_in_quotes(','.join(keys)),
+                self._get_string_in_quotes(self.start_time),
+                self._get_string_in_quotes(self.end_time),
+                self._get_string_in_quotes(transform_desc),
+                self._get_string_in_quotes(display)
+            )
+        elif re.search('ods', self.client, re.IGNORECASE):
+            command = (
+                self.client + ' ' +
+                '--stime=' + self._get_ods_cli_stime(self.start_time) + ' ' +
+                '--fburlonly ' +
+                self._get_string_in_quotes(entities) + ' ' +
+                self._get_string_in_quotes(','.join(keys)) + ' ' +
+                self._get_string_in_quotes(transform_desc)
+            )
+        self.execute_script(command)
+        url = ""
+        with open(self.OUTPUT_FILE, 'r') as fp:
+            url = fp.readline()
+        return url
diff --git a/src/rocksdb/tools/advisor/advisor/db_timeseries_parser.py b/src/rocksdb/tools/advisor/advisor/db_timeseries_parser.py
new file mode 100644
index 00000000..308eb139
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/db_timeseries_parser.py
@@ -0,0 +1,208 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from abc import abstractmethod
+from advisor.db_log_parser import DataSource
+from enum import Enum
+import math
+
+
+NO_ENTITY = 'ENTITY_PLACEHOLDER'
+
+
+class TimeSeriesData(DataSource):
+    class Behavior(Enum):
+        bursty = 1
+        evaluate_expression = 2
+
+    class AggregationOperator(Enum):
+        avg = 1
+        max = 2
+        min = 3
+        latest = 4
+        oldest = 5
+
+    def __init__(self):
+        super().__init__(DataSource.Type.TIME_SERIES)
+        self.keys_ts = None  # Dict[entity, Dict[key, Dict[timestamp, value]]]
+        self.stats_freq_sec = None
+
+    @abstractmethod
+    def get_keys_from_conditions(self, conditions):
+        # This method takes in a list of time-series conditions; for each
+        # condition it manipulates the 'keys' in the way that is supported by
+        # the subclass implementing this method
+        pass
+
+    @abstractmethod
+    def fetch_timeseries(self, required_statistics):
+        # this method takes in a list of statistics and fetches the timeseries
+        # for each of them and populates the 'keys_ts' dictionary
+        pass
+
+    def fetch_burst_epochs(
+        self, entities, statistic, window_sec, threshold, percent
+    ):
+        # type: (str, int, float, bool) -> Dict[str, Dict[int, float]]
+        # this method calculates the (percent) rate change in the 'statistic'
+        # for each entity (over 'window_sec' seconds) and returns the epochs
+        # where this rate change is greater than or equal to the 'threshold'
+        # value
+        if self.stats_freq_sec == 0:
+            # not time series data, cannot check for bursty behavior
+            return
+        if window_sec < self.stats_freq_sec:
+            window_sec = self.stats_freq_sec
+        # 'window_samples' is the number of windows to go back to
+        # compare the current window with, while calculating rate change.
+        window_samples = math.ceil(window_sec / self.stats_freq_sec)
+        burst_epochs = {}
+        # if percent = False:
+        # curr_val = value at window for which rate change is being calculated
+        # prev_val = value at window that is window_samples behind curr_window
+        # Then rate_without_percent =
+        # ((curr_val-prev_val)*duration_sec)/(curr_timestamp-prev_timestamp)
+        # if percent = True:
+        # rate_with_percent = (rate_without_percent * 100) / prev_val
+        # These calculations are in line with the rate() transform supported
+        # by ODS
+        for entity in entities:
+            if statistic not in self.keys_ts[entity]:
+                continue
+            timestamps = sorted(list(self.keys_ts[entity][statistic].keys()))
+            for ix in range(window_samples, len(timestamps), 1):
+                first_ts = timestamps[ix - window_samples]
+                last_ts = timestamps[ix]
+                first_val = self.keys_ts[entity][statistic][first_ts]
+                last_val = self.keys_ts[entity][statistic][last_ts]
+                diff = last_val - first_val
+                if percent:
+                    diff = diff * 100 / first_val
+                rate = (diff * self.duration_sec) / (last_ts - first_ts)
+                # if the rate change is greater than the provided threshold,
+                # then the condition is triggered for entity at time 'last_ts'
+                if rate >= threshold:
+                    if entity not in burst_epochs:
+                        burst_epochs[entity] = {}
+                    burst_epochs[entity][last_ts] = rate
+        return burst_epochs
+
+    def fetch_aggregated_values(self, entity, statistics, aggregation_op):
+        # type: (str, AggregationOperator) -> Dict[str, float]
+        # this method performs the aggregation specified by 'aggregation_op'
+        # on the timeseries of 'statistics' for 'entity' and returns:
+        # Dict[statistic, aggregated_value]
+        result = {}
+        for stat in statistics:
+            if stat not in self.keys_ts[entity]:
+                continue
+            agg_val = None
+            if aggregation_op is self.AggregationOperator.latest:
+                latest_timestamp = max(list(self.keys_ts[entity][stat].keys()))
+                agg_val = self.keys_ts[entity][stat][latest_timestamp]
+            elif aggregation_op is self.AggregationOperator.oldest:
+                oldest_timestamp = min(list(self.keys_ts[entity][stat].keys()))
+                agg_val = self.keys_ts[entity][stat][oldest_timestamp]
+            elif aggregation_op is self.AggregationOperator.max:
+                agg_val = max(list(self.keys_ts[entity][stat].values()))
+            elif aggregation_op is self.AggregationOperator.min:
+                agg_val = min(list(self.keys_ts[entity][stat].values()))
+            elif aggregation_op is self.AggregationOperator.avg:
+                values = list(self.keys_ts[entity][stat].values())
+                agg_val = sum(values) / len(values)
+            result[stat] = agg_val
+        return result
+
+    def check_and_trigger_conditions(self, conditions):
+        # get the list of statistics that need to be fetched
+        reqd_keys = self.get_keys_from_conditions(conditions)
+        # fetch the required statistics and populate the map 'keys_ts'
+        self.fetch_timeseries(reqd_keys)
+        # Trigger the appropriate conditions
+        for cond in conditions:
+            complete_keys = self.get_keys_from_conditions([cond])
+            # Get the entities that have all statistics required by 'cond':
+            # an entity is checked for a given condition only if we possess all
+            # of the condition's 'keys' for that entity
+            entities_with_stats = []
+            for entity in self.keys_ts:
+                stat_missing = False
+                for stat in complete_keys:
+                    if stat not in self.keys_ts[entity]:
+                        stat_missing = True
+                        break
+                if not stat_missing:
+                    entities_with_stats.append(entity)
+            if not entities_with_stats:
+                continue
+            if cond.behavior is self.Behavior.bursty:
+                # for a condition that checks for bursty behavior, only one key
+                # should be present in the condition's 'keys' field
+                result = self.fetch_burst_epochs(
+                    entities_with_stats,
+                    complete_keys[0],  # there should be only one key
+                    cond.window_sec,
+                    cond.rate_threshold,
+                    True
+                )
+                # Trigger in this case is:
+                # Dict[entity_name, Dict[timestamp, rate_change]]
+                # where the inner dictionary contains rate_change values when
+                # the rate_change >= threshold provided, with the
+                # corresponding timestamps
+                if result:
+                    cond.set_trigger(result)
+            elif cond.behavior is self.Behavior.evaluate_expression:
+                self.handle_evaluate_expression(
+                    cond,
+                    complete_keys,
+                    entities_with_stats
+                )
+
+    def handle_evaluate_expression(self, condition, statistics, entities):
+        trigger = {}
+        # check 'condition' for each of these entities
+        for entity in entities:
+            if hasattr(condition, 'aggregation_op'):
+                # in this case, the aggregation operation is performed on each
+                # of the condition's 'keys' and then with aggregated values
+                # condition's 'expression' is evaluated; if it evaluates to
+                # True, then list of the keys values is added to the
+                # condition's trigger: Dict[entity_name, List[stats]]
+                result = self.fetch_aggregated_values(
+                        entity, statistics, condition.aggregation_op
+                )
+                keys = [result[key] for key in statistics]
+                try:
+                    if eval(condition.expression):
+                        trigger[entity] = keys
+                except Exception as e:
+                    print(
+                        'WARNING(TimeSeriesData) check_and_trigger: ' + str(e)
+                    )
+            else:
+                # assumption: all stats have same series of timestamps
+                # this is similar to the above but 'expression' is evaluated at
+                # each timestamp, since there is no aggregation, and all the
+                # epochs are added to the trigger when the condition's
+                # 'expression' evaluated to true; so trigger is:
+                # Dict[entity, Dict[timestamp, List[stats]]]
+                for epoch in self.keys_ts[entity][statistics[0]].keys():
+                    keys = [
+                        self.keys_ts[entity][key][epoch]
+                        for key in statistics
+                    ]
+                    try:
+                        if eval(condition.expression):
+                            if entity not in trigger:
+                                trigger[entity] = {}
+                            trigger[entity][epoch] = keys
+                    except Exception as e:
+                        print(
+                            'WARNING(TimeSeriesData) check_and_trigger: ' +
+                            str(e)
+                        )
+        if trigger:
+            condition.set_trigger(trigger)
diff --git a/src/rocksdb/tools/advisor/advisor/ini_parser.py b/src/rocksdb/tools/advisor/advisor/ini_parser.py
new file mode 100644
index 00000000..4776ef20
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/ini_parser.py
@@ -0,0 +1,76 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from enum import Enum
+
+
+class IniParser:
+    class Element(Enum):
+        rule = 1
+        cond = 2
+        sugg = 3
+        key_val = 4
+        comment = 5
+
+    @staticmethod
+    def remove_trailing_comment(line):
+        line = line.strip()
+        comment_start = line.find('#')
+        if comment_start > -1:
+            return line[:comment_start]
+        return line
+
+    @staticmethod
+    def is_section_header(line):
+        # A section header looks like: [Rule "my-new-rule"]. Essentially,
+        # a line that is in square-brackets.
+        line = line.strip()
+        if line.startswith('[') and line.endswith(']'):
+            return True
+        return False
+
+    @staticmethod
+    def get_section_name(line):
+        # For a section header: [Rule "my-new-rule"], this method will return
+        # "my-new-rule".
+        token_list = line.strip()[1:-1].split('"')
+        if len(token_list) < 3:
+            error = 'needed section header: [<section_type> "<section_name>"]'
+            raise ValueError('Parsing error: ' + error + '\n' + line)
+        return token_list[1]
+
+    @staticmethod
+    def get_element(line):
+        line = IniParser.remove_trailing_comment(line)
+        if not line:
+            return IniParser.Element.comment
+        if IniParser.is_section_header(line):
+            if line.strip()[1:-1].startswith('Suggestion'):
+                return IniParser.Element.sugg
+            if line.strip()[1:-1].startswith('Rule'):
+                return IniParser.Element.rule
+            if line.strip()[1:-1].startswith('Condition'):
+                return IniParser.Element.cond
+        if '=' in line:
+            return IniParser.Element.key_val
+        error = 'not a recognizable RulesSpec element'
+        raise ValueError('Parsing error: ' + error + '\n' + line)
+
+    @staticmethod
+    def get_key_value_pair(line):
+        line = line.strip()
+        key = line.split('=')[0].strip()
+        value = "=".join(line.split('=')[1:])
+        if value == "":  # if the option has no value
+            return (key, None)
+        values = IniParser.get_list_from_value(value)
+        if len(values) == 1:
+            return (key, value)
+        return (key, values)
+
+    @staticmethod
+    def get_list_from_value(value):
+        values = value.strip().split(':')
+        return values
diff --git a/src/rocksdb/tools/advisor/advisor/rule_parser.py b/src/rocksdb/tools/advisor/advisor/rule_parser.py
new file mode 100644
index 00000000..592218f4
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/rule_parser.py
@@ -0,0 +1,528 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from abc import ABC, abstractmethod
+from advisor.db_log_parser import DataSource, NO_COL_FAMILY
+from advisor.db_timeseries_parser import TimeSeriesData
+from enum import Enum
+from advisor.ini_parser import IniParser
+import re
+
+
+class Section(ABC):
+    def __init__(self, name):
+        self.name = name
+
+    @abstractmethod
+    def set_parameter(self, key, value):
+        pass
+
+    @abstractmethod
+    def perform_checks(self):
+        pass
+
+
+class Rule(Section):
+    def __init__(self, name):
+        super().__init__(name)
+        self.conditions = None
+        self.suggestions = None
+        self.overlap_time_seconds = None
+        self.trigger_entities = None
+        self.trigger_column_families = None
+
+    def set_parameter(self, key, value):
+        # If the Rule is associated with a single suggestion/condition, then
+        # value will be a string and not a list. Hence, convert it to a single
+        # element list before storing it in self.suggestions or
+        # self.conditions.
+        if key == 'conditions':
+            if isinstance(value, str):
+                self.conditions = [value]
+            else:
+                self.conditions = value
+        elif key == 'suggestions':
+            if isinstance(value, str):
+                self.suggestions = [value]
+            else:
+                self.suggestions = value
+        elif key == 'overlap_time_period':
+            self.overlap_time_seconds = value
+
+    def get_suggestions(self):
+        return self.suggestions
+
+    def perform_checks(self):
+        if not self.conditions or len(self.conditions) < 1:
+            raise ValueError(
+                self.name + ': rule must have at least one condition'
+            )
+        if not self.suggestions or len(self.suggestions) < 1:
+            raise ValueError(
+                self.name + ': rule must have at least one suggestion'
+            )
+        if self.overlap_time_seconds:
+            if len(self.conditions) != 2:
+                raise ValueError(
+                    self.name + ": rule must be associated with 2 conditions\
+                    in order to check for a time dependency between them"
+                )
+            time_format = '^\d+[s|m|h|d]$'
+            if (
+                not
+                re.match(time_format, self.overlap_time_seconds, re.IGNORECASE)
+            ):
+                raise ValueError(
+                    self.name + ": overlap_time_seconds format: \d+[s|m|h|d]"
+                )
+            else:  # convert to seconds
+                in_seconds = int(self.overlap_time_seconds[:-1])
+                if self.overlap_time_seconds[-1] == 'm':
+                    in_seconds *= 60
+                elif self.overlap_time_seconds[-1] == 'h':
+                    in_seconds *= (60 * 60)
+                elif self.overlap_time_seconds[-1] == 'd':
+                    in_seconds *= (24 * 60 * 60)
+                self.overlap_time_seconds = in_seconds
+
+    def get_overlap_timestamps(self, key1_trigger_epochs, key2_trigger_epochs):
+        # this method takes in 2 timeseries i.e. timestamps at which the
+        # rule's 2 TIME_SERIES conditions were triggered and it finds
+        # (if present) the first pair of timestamps at which the 2 conditions
+        # were triggered within 'overlap_time_seconds' of each other
+        key1_lower_bounds = [
+            epoch - self.overlap_time_seconds
+            for epoch in key1_trigger_epochs
+        ]
+        key1_lower_bounds.sort()
+        key2_trigger_epochs.sort()
+        trigger_ix = 0
+        overlap_pair = None
+        for key1_lb in key1_lower_bounds:
+            while (
+                key2_trigger_epochs[trigger_ix] < key1_lb and
+                trigger_ix < len(key2_trigger_epochs)
+            ):
+                trigger_ix += 1
+            if trigger_ix >= len(key2_trigger_epochs):
+                break
+            if (
+                key2_trigger_epochs[trigger_ix] <=
+                key1_lb + (2 * self.overlap_time_seconds)
+            ):
+                overlap_pair = (
+                    key2_trigger_epochs[trigger_ix],
+                    key1_lb + self.overlap_time_seconds
+                )
+                break
+        return overlap_pair
+
+    def get_trigger_entities(self):
+        return self.trigger_entities
+
+    def get_trigger_column_families(self):
+        return self.trigger_column_families
+
+    def is_triggered(self, conditions_dict, column_families):
+        if self.overlap_time_seconds:
+            condition1 = conditions_dict[self.conditions[0]]
+            condition2 = conditions_dict[self.conditions[1]]
+            if not (
+                condition1.get_data_source() is DataSource.Type.TIME_SERIES and
+                condition2.get_data_source() is DataSource.Type.TIME_SERIES
+            ):
+                raise ValueError(self.name + ': need 2 timeseries conditions')
+
+            map1 = condition1.get_trigger()
+            map2 = condition2.get_trigger()
+            if not (map1 and map2):
+                return False
+
+            self.trigger_entities = {}
+            is_triggered = False
+            entity_intersection = (
+                set(map1.keys()).intersection(set(map2.keys()))
+            )
+            for entity in entity_intersection:
+                overlap_timestamps_pair = (
+                    self.get_overlap_timestamps(
+                        list(map1[entity].keys()), list(map2[entity].keys())
+                    )
+                )
+                if overlap_timestamps_pair:
+                    self.trigger_entities[entity] = overlap_timestamps_pair
+                    is_triggered = True
+            if is_triggered:
+                self.trigger_column_families = set(column_families)
+            return is_triggered
+        else:
+            all_conditions_triggered = True
+            self.trigger_column_families = set(column_families)
+            for cond_name in self.conditions:
+                cond = conditions_dict[cond_name]
+                if not cond.get_trigger():
+                    all_conditions_triggered = False
+                    break
+                if (
+                    cond.get_data_source() is DataSource.Type.LOG or
+                    cond.get_data_source() is DataSource.Type.DB_OPTIONS
+                ):
+                    cond_col_fam = set(cond.get_trigger().keys())
+                    if NO_COL_FAMILY in cond_col_fam:
+                        cond_col_fam = set(column_families)
+                    self.trigger_column_families = (
+                        self.trigger_column_families.intersection(cond_col_fam)
+                    )
+                elif cond.get_data_source() is DataSource.Type.TIME_SERIES:
+                    cond_entities = set(cond.get_trigger().keys())
+                    if self.trigger_entities is None:
+                        self.trigger_entities = cond_entities
+                    else:
+                        self.trigger_entities = (
+                            self.trigger_entities.intersection(cond_entities)
+                        )
+                if not (self.trigger_entities or self.trigger_column_families):
+                    all_conditions_triggered = False
+                    break
+            if not all_conditions_triggered:  # clean up if rule not triggered
+                self.trigger_column_families = None
+                self.trigger_entities = None
+            return all_conditions_triggered
+
+    def __repr__(self):
+        # Append conditions
+        rule_string = "Rule: " + self.name + " has conditions:: "
+        is_first = True
+        for cond in self.conditions:
+            if is_first:
+                rule_string += cond
+                is_first = False
+            else:
+                rule_string += (" AND " + cond)
+        # Append suggestions
+        rule_string += "\nsuggestions:: "
+        is_first = True
+        for sugg in self.suggestions:
+            if is_first:
+                rule_string += sugg
+                is_first = False
+            else:
+                rule_string += (", " + sugg)
+        if self.trigger_entities:
+            rule_string += (', entities:: ' + str(self.trigger_entities))
+        if self.trigger_column_families:
+            rule_string += (', col_fam:: ' + str(self.trigger_column_families))
+        # Return constructed string
+        return rule_string
+
+
+class Suggestion(Section):
+    class Action(Enum):
+        set = 1
+        increase = 2
+        decrease = 3
+
+    def __init__(self, name):
+        super().__init__(name)
+        self.option = None
+        self.action = None
+        self.suggested_values = None
+        self.description = None
+
+    def set_parameter(self, key, value):
+        if key == 'option':
+            # Note:
+            # case 1: 'option' is supported by Rocksdb OPTIONS file; in this
+            # case the option belongs to one of the sections in the config
+            # file and it's name is prefixed by "<section_type>."
+            # case 2: 'option' is not supported by Rocksdb OPTIONS file; the
+            # option is not expected to have the character '.' in its name
+            self.option = value
+        elif key == 'action':
+            if self.option and not value:
+                raise ValueError(self.name + ': provide action for option')
+            self.action = self.Action[value]
+        elif key == 'suggested_values':
+            if isinstance(value, str):
+                self.suggested_values = [value]
+            else:
+                self.suggested_values = value
+        elif key == 'description':
+            self.description = value
+
+    def perform_checks(self):
+        if not self.description:
+            if not self.option:
+                raise ValueError(self.name + ': provide option or description')
+            if not self.action:
+                raise ValueError(self.name + ': provide action for option')
+            if self.action is self.Action.set and not self.suggested_values:
+                raise ValueError(
+                    self.name + ': provide suggested value for option'
+                )
+
+    def __repr__(self):
+        sugg_string = "Suggestion: " + self.name
+        if self.description:
+            sugg_string += (' description : ' + self.description)
+        else:
+            sugg_string += (
+                ' option : ' + self.option + ' action : ' + self.action.name
+            )
+            if self.suggested_values:
+                sugg_string += (
+                    ' suggested_values : ' + str(self.suggested_values)
+                )
+        return sugg_string
+
+
+class Condition(Section):
+    def __init__(self, name):
+        super().__init__(name)
+        self.data_source = None
+        self.trigger = None
+
+    def perform_checks(self):
+        if not self.data_source:
+            raise ValueError(self.name + ': condition not tied to data source')
+
+    def set_data_source(self, data_source):
+        self.data_source = data_source
+
+    def get_data_source(self):
+        return self.data_source
+
+    def reset_trigger(self):
+        self.trigger = None
+
+    def set_trigger(self, condition_trigger):
+        self.trigger = condition_trigger
+
+    def get_trigger(self):
+        return self.trigger
+
+    def is_triggered(self):
+        if self.trigger:
+            return True
+        return False
+
+    def set_parameter(self, key, value):
+        # must be defined by the subclass
+        raise NotImplementedError(self.name + ': provide source for condition')
+
+
+class LogCondition(Condition):
+    @classmethod
+    def create(cls, base_condition):
+        base_condition.set_data_source(DataSource.Type['LOG'])
+        base_condition.__class__ = cls
+        return base_condition
+
+    def set_parameter(self, key, value):
+        if key == 'regex':
+            self.regex = value
+
+    def perform_checks(self):
+        super().perform_checks()
+        if not self.regex:
+            raise ValueError(self.name + ': provide regex for log condition')
+
+    def __repr__(self):
+        log_cond_str = "LogCondition: " + self.name
+        log_cond_str += (" regex: " + self.regex)
+        # if self.trigger:
+        #     log_cond_str += (" trigger: " + str(self.trigger))
+        return log_cond_str
+
+
+class OptionCondition(Condition):
+    @classmethod
+    def create(cls, base_condition):
+        base_condition.set_data_source(DataSource.Type['DB_OPTIONS'])
+        base_condition.__class__ = cls
+        return base_condition
+
+    def set_parameter(self, key, value):
+        if key == 'options':
+            if isinstance(value, str):
+                self.options = [value]
+            else:
+                self.options = value
+        elif key == 'evaluate':
+            self.eval_expr = value
+
+    def perform_checks(self):
+        super().perform_checks()
+        if not self.options:
+            raise ValueError(self.name + ': options missing in condition')
+        if not self.eval_expr:
+            raise ValueError(self.name + ': expression missing in condition')
+
+    def __repr__(self):
+        opt_cond_str = "OptionCondition: " + self.name
+        opt_cond_str += (" options: " + str(self.options))
+        opt_cond_str += (" expression: " + self.eval_expr)
+        if self.trigger:
+            opt_cond_str += (" trigger: " + str(self.trigger))
+        return opt_cond_str
+
+
+class TimeSeriesCondition(Condition):
+    @classmethod
+    def create(cls, base_condition):
+        base_condition.set_data_source(DataSource.Type['TIME_SERIES'])
+        base_condition.__class__ = cls
+        return base_condition
+
+    def set_parameter(self, key, value):
+        if key == 'keys':
+            if isinstance(value, str):
+                self.keys = [value]
+            else:
+                self.keys = value
+        elif key == 'behavior':
+            self.behavior = TimeSeriesData.Behavior[value]
+        elif key == 'rate_threshold':
+            self.rate_threshold = float(value)
+        elif key == 'window_sec':
+            self.window_sec = int(value)
+        elif key == 'evaluate':
+            self.expression = value
+        elif key == 'aggregation_op':
+            self.aggregation_op = TimeSeriesData.AggregationOperator[value]
+
+    def perform_checks(self):
+        if not self.keys:
+            raise ValueError(self.name + ': specify timeseries key')
+        if not self.behavior:
+            raise ValueError(self.name + ': specify triggering behavior')
+        if self.behavior is TimeSeriesData.Behavior.bursty:
+            if not self.rate_threshold:
+                raise ValueError(self.name + ': specify rate burst threshold')
+            if not self.window_sec:
+                self.window_sec = 300  # default window length is 5 minutes
+            if len(self.keys) > 1:
+                raise ValueError(self.name + ': specify only one key')
+        elif self.behavior is TimeSeriesData.Behavior.evaluate_expression:
+            if not (self.expression):
+                raise ValueError(self.name + ': specify evaluation expression')
+        else:
+            raise ValueError(self.name + ': trigger behavior not supported')
+
+    def __repr__(self):
+        ts_cond_str = "TimeSeriesCondition: " + self.name
+        ts_cond_str += (" statistics: " + str(self.keys))
+        ts_cond_str += (" behavior: " + self.behavior.name)
+        if self.behavior is TimeSeriesData.Behavior.bursty:
+            ts_cond_str += (" rate_threshold: " + str(self.rate_threshold))
+            ts_cond_str += (" window_sec: " + str(self.window_sec))
+        if self.behavior is TimeSeriesData.Behavior.evaluate_expression:
+            ts_cond_str += (" expression: " + self.expression)
+            if hasattr(self, 'aggregation_op'):
+                ts_cond_str += (" aggregation_op: " + self.aggregation_op.name)
+        if self.trigger:
+            ts_cond_str += (" trigger: " + str(self.trigger))
+        return ts_cond_str
+
+
+class RulesSpec:
+    def __init__(self, rules_path):
+        self.file_path = rules_path
+
+    def initialise_fields(self):
+        self.rules_dict = {}
+        self.conditions_dict = {}
+        self.suggestions_dict = {}
+
+    def perform_section_checks(self):
+        for rule in self.rules_dict.values():
+            rule.perform_checks()
+        for cond in self.conditions_dict.values():
+            cond.perform_checks()
+        for sugg in self.suggestions_dict.values():
+            sugg.perform_checks()
+
+    def load_rules_from_spec(self):
+        self.initialise_fields()
+        with open(self.file_path, 'r') as db_rules:
+            curr_section = None
+            for line in db_rules:
+                line = IniParser.remove_trailing_comment(line)
+                if not line:
+                    continue
+                element = IniParser.get_element(line)
+                if element is IniParser.Element.comment:
+                    continue
+                elif element is not IniParser.Element.key_val:
+                    curr_section = element  # it's a new IniParser header
+                    section_name = IniParser.get_section_name(line)
+                    if element is IniParser.Element.rule:
+                        new_rule = Rule(section_name)
+                        self.rules_dict[section_name] = new_rule
+                    elif element is IniParser.Element.cond:
+                        new_cond = Condition(section_name)
+                        self.conditions_dict[section_name] = new_cond
+                    elif element is IniParser.Element.sugg:
+                        new_suggestion = Suggestion(section_name)
+                        self.suggestions_dict[section_name] = new_suggestion
+                elif element is IniParser.Element.key_val:
+                    key, value = IniParser.get_key_value_pair(line)
+                    if curr_section is IniParser.Element.rule:
+                        new_rule.set_parameter(key, value)
+                    elif curr_section is IniParser.Element.cond:
+                        if key == 'source':
+                            if value == 'LOG':
+                                new_cond = LogCondition.create(new_cond)
+                            elif value == 'OPTIONS':
+                                new_cond = OptionCondition.create(new_cond)
+                            elif value == 'TIME_SERIES':
+                                new_cond = TimeSeriesCondition.create(new_cond)
+                        else:
+                            new_cond.set_parameter(key, value)
+                    elif curr_section is IniParser.Element.sugg:
+                        new_suggestion.set_parameter(key, value)
+
+    def get_rules_dict(self):
+        return self.rules_dict
+
+    def get_conditions_dict(self):
+        return self.conditions_dict
+
+    def get_suggestions_dict(self):
+        return self.suggestions_dict
+
+    def get_triggered_rules(self, data_sources, column_families):
+        self.trigger_conditions(data_sources)
+        triggered_rules = []
+        for rule in self.rules_dict.values():
+            if rule.is_triggered(self.conditions_dict, column_families):
+                triggered_rules.append(rule)
+        return triggered_rules
+
+    def trigger_conditions(self, data_sources):
+        for source_type in data_sources:
+            cond_subset = [
+                cond
+                for cond in self.conditions_dict.values()
+                if cond.get_data_source() is source_type
+            ]
+            if not cond_subset:
+                continue
+            for source in data_sources[source_type]:
+                source.check_and_trigger_conditions(cond_subset)
+
+    def print_rules(self, rules):
+        for rule in rules:
+            print('\nRule: ' + rule.name)
+            for cond_name in rule.conditions:
+                print(repr(self.conditions_dict[cond_name]))
+            for sugg_name in rule.suggestions:
+                print(repr(self.suggestions_dict[sugg_name]))
+            if rule.trigger_entities:
+                print('scope: entities:')
+                print(rule.trigger_entities)
+            if rule.trigger_column_families:
+                print('scope: col_fam:')
+                print(rule.trigger_column_families)
diff --git a/src/rocksdb/tools/advisor/advisor/rule_parser_example.py b/src/rocksdb/tools/advisor/advisor/rule_parser_example.py
new file mode 100644
index 00000000..d2348e5a
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/rule_parser_example.py
@@ -0,0 +1,89 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from advisor.rule_parser import RulesSpec
+from advisor.db_log_parser import DatabaseLogs, DataSource
+from advisor.db_options_parser import DatabaseOptions
+from advisor.db_stats_fetcher import LogStatsParser, OdsStatsFetcher
+import argparse
+
+
+def main(args):
+    # initialise the RulesSpec parser
+    rule_spec_parser = RulesSpec(args.rules_spec)
+    rule_spec_parser.load_rules_from_spec()
+    rule_spec_parser.perform_section_checks()
+    # initialize the DatabaseOptions object
+    db_options = DatabaseOptions(args.rocksdb_options)
+    # Create DatabaseLogs object
+    db_logs = DatabaseLogs(
+        args.log_files_path_prefix, db_options.get_column_families()
+    )
+    # Create the Log STATS object
+    db_log_stats = LogStatsParser(
+        args.log_files_path_prefix, args.stats_dump_period_sec
+    )
+    data_sources = {
+        DataSource.Type.DB_OPTIONS: [db_options],
+        DataSource.Type.LOG: [db_logs],
+        DataSource.Type.TIME_SERIES: [db_log_stats]
+    }
+    if args.ods_client:
+        data_sources[DataSource.Type.TIME_SERIES].append(OdsStatsFetcher(
+            args.ods_client,
+            args.ods_entity,
+            args.ods_tstart,
+            args.ods_tend,
+            args.ods_key_prefix
+        ))
+    triggered_rules = rule_spec_parser.get_triggered_rules(
+        data_sources, db_options.get_column_families()
+    )
+    rule_spec_parser.print_rules(triggered_rules)
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description='Use this script to get\
+        suggestions for improving Rocksdb performance.')
+    parser.add_argument(
+        '--rules_spec', required=True, type=str,
+        help='path of the file containing the expert-specified Rules'
+    )
+    parser.add_argument(
+        '--rocksdb_options', required=True, type=str,
+        help='path of the starting Rocksdb OPTIONS file'
+    )
+    parser.add_argument(
+        '--log_files_path_prefix', required=True, type=str,
+        help='path prefix of the Rocksdb LOG files'
+    )
+    parser.add_argument(
+        '--stats_dump_period_sec', required=True, type=int,
+        help='the frequency (in seconds) at which STATISTICS are printed to ' +
+        'the Rocksdb LOG file'
+    )
+    # ODS arguments
+    parser.add_argument(
+        '--ods_client', type=str, help='the ODS client binary'
+    )
+    parser.add_argument(
+        '--ods_entity', type=str,
+        help='the servers for which the ODS stats need to be fetched'
+    )
+    parser.add_argument(
+        '--ods_key_prefix', type=str,
+        help='the prefix that needs to be attached to the keys of time ' +
+        'series to be fetched from ODS'
+    )
+    parser.add_argument(
+        '--ods_tstart', type=int,
+        help='start time of timeseries to be fetched from ODS'
+    )
+    parser.add_argument(
+        '--ods_tend', type=int,
+        help='end time of timeseries to be fetched from ODS'
+    )
+    args = parser.parse_args()
+    main(args)
diff --git a/src/rocksdb/tools/advisor/advisor/rules.ini b/src/rocksdb/tools/advisor/advisor/rules.ini
new file mode 100644
index 00000000..ec7a07e6
--- /dev/null
+++ b/src/rocksdb/tools/advisor/advisor/rules.ini
@@ -0,0 +1,214 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+#
+# FORMAT: very similar to the Rocksdb ini file in terms of syntax
+# (refer rocksdb/examples/rocksdb_option_file_example.ini)
+#
+# The Rules INI file is made up of multiple sections and each section is made
+# up of multiple key-value pairs. The recognized section types are:
+# Rule, Suggestion, Condition. Each section must have a name specified in ""
+# in the section header. This name acts as an identifier in that section
+# type's namespace. A section header looks like:
+# [<section_type> "<section_name_identifier>"]
+#
+# There should be at least one Rule section in the file with its corresponding
+# Condition and Suggestion sections. A Rule is triggered only when all of its
+# conditions are triggered. The order in which a Rule's conditions and
+# suggestions are specified has no significance.
+#
+# A Condition must be associated with a data source specified by the parameter
+# 'source' and this must be the first parameter specified for the Condition.
+# A condition can be associated with one or more Rules.
+#
+# A Suggestion is an advised change to a Rocksdb option to improve the
+# performance of the database in some way. Every suggestion can be a part of
+# one or more Rules.
+
+[Rule "stall-too-many-memtables"]
+suggestions=inc-bg-flush:inc-write-buffer
+conditions=stall-too-many-memtables
+
+[Condition "stall-too-many-memtables"]
+source=LOG
+regex=Stopping writes because we have \d+ immutable memtables \(waiting for flush\), max_write_buffer_number is set to \d+
+
+[Rule "stall-too-many-L0"]
+suggestions=inc-max-subcompactions:inc-max-bg-compactions:inc-write-buffer-size:dec-max-bytes-for-level-base:inc-l0-slowdown-writes-trigger
+conditions=stall-too-many-L0
+
+[Condition "stall-too-many-L0"]
+source=LOG
+regex=Stalling writes because we have \d+ level-0 files
+
+[Rule "stop-too-many-L0"]
+suggestions=inc-max-bg-compactions:inc-write-buffer-size:inc-l0-stop-writes-trigger
+conditions=stop-too-many-L0
+
+[Condition "stop-too-many-L0"]
+source=LOG
+regex=Stopping writes because we have \d+ level-0 files
+
+[Rule "stall-too-many-compaction-bytes"]
+suggestions=inc-max-bg-compactions:inc-write-buffer-size:inc-hard-pending-compaction-bytes-limit:inc-soft-pending-compaction-bytes-limit
+conditions=stall-too-many-compaction-bytes
+
+[Condition "stall-too-many-compaction-bytes"]
+source=LOG
+regex=Stalling writes because of estimated pending compaction bytes \d+
+
+[Suggestion "inc-bg-flush"]
+option=DBOptions.max_background_flushes
+action=increase
+suggested_values=2
+
+[Suggestion "inc-write-buffer"]
+option=CFOptions.max_write_buffer_number
+action=increase
+
+[Suggestion "inc-max-subcompactions"]
+option=DBOptions.max_subcompactions
+action=increase
+
+[Suggestion "inc-max-bg-compactions"]
+option=DBOptions.max_background_compactions
+action=increase
+suggested_values=2
+
+[Suggestion "inc-write-buffer-size"]
+option=CFOptions.write_buffer_size
+action=increase
+
+[Suggestion "dec-max-bytes-for-level-base"]
+option=CFOptions.max_bytes_for_level_base
+action=decrease
+
+[Suggestion "inc-l0-slowdown-writes-trigger"]
+option=CFOptions.level0_slowdown_writes_trigger
+action=increase
+
+[Suggestion "inc-l0-stop-writes-trigger"]
+option=CFOptions.level0_stop_writes_trigger
+action=increase
+
+[Suggestion "inc-hard-pending-compaction-bytes-limit"]
+option=CFOptions.hard_pending_compaction_bytes_limit
+action=increase
+
+[Suggestion "inc-soft-pending-compaction-bytes-limit"]
+option=CFOptions.soft_pending_compaction_bytes_limit
+action=increase
+
+[Rule "level0-level1-ratio"]
+conditions=level0-level1-ratio
+suggestions=inc-base-max-bytes
+
+[Condition "level0-level1-ratio"]
+source=OPTIONS
+options=CFOptions.level0_file_num_compaction_trigger:CFOptions.write_buffer_size:CFOptions.max_bytes_for_level_base
+evaluate=int(options[0])*int(options[1])-int(options[2])>=1  # should evaluate to a boolean, condition triggered if evaluates to true
+
+[Suggestion "inc-base-max-bytes"]
+option=CFOptions.max_bytes_for_level_base
+action=increase
+
+[Rules "tuning-iostat-burst"]
+conditions=large-db-get-p99
+suggestions=bytes-per-sync-non0:wal-bytes-per-sync-non0:set-rate-limiter
+#overlap_time_period=10m
+
+[Condition "write-burst"]
+source=TIME_SERIES
+keys=dyno.flash_write_bytes_per_sec
+behavior=bursty
+window_sec=300  # the smaller this window, the more sensitivity to changes in the time series, so the rate_threshold should be bigger; when it's 60, then same as diff(%)
+rate_threshold=20
+
+[Condition "large-p99-read-latency"]
+source=TIME_SERIES
+keys=[]rocksdb.read.block.get.micros.p99
+behavior=bursty
+window_sec=300
+rate_threshold=10
+
+[Condition "large-db-get-p99"]
+source=TIME_SERIES
+keys=[]rocksdb.db.get.micros.p50:[]rocksdb.db.get.micros.p99
+behavior=evaluate_expression
+evaluate=(keys[1]/keys[0])>5
+
+[Suggestion "bytes-per-sync-non0"]
+option=DBOptions.bytes_per_sync
+action=set
+suggested_values=1048576
+
+[Suggestion "wal-bytes-per-sync-non0"]
+option=DBOptions.wal_bytes_per_sync
+action=set
+suggested_values=1048576
+
+[Suggestion "set-rate-limiter"]
+option=rate_limiter_bytes_per_sec
+action=set
+suggested_values=1024000
+
+[Rule "bloom-filter-percent-useful"]
+conditions=bloom-filter-percent-useful
+suggestions=inc-bloom-bits-per-key
+
+[Condition "bloom-filter-percent-useful"]
+source=TIME_SERIES
+keys=[]rocksdb.bloom.filter.useful.count:[]rocksdb.bloom.filter.full.positive.count:[]rocksdb.bloom.filter.full.true.positive.count
+behavior=evaluate_expression
+evaluate=((keys[0]+keys[2])/(keys[0]+keys[1]))<0.9  # should evaluate to a boolean
+aggregation_op=latest
+
+[Rule "bloom-not-enabled"]
+conditions=bloom-not-enabled
+suggestions=inc-bloom-bits-per-key
+
+[Condition "bloom-not-enabled"]
+source=TIME_SERIES
+keys=[]rocksdb.bloom.filter.useful.count:[]rocksdb.bloom.filter.full.positive.count:[]rocksdb.bloom.filter.full.true.positive.count
+behavior=evaluate_expression
+evaluate=keys[0]+keys[1]+keys[2]==0
+aggregation_op=avg
+
+[Suggestion "inc-bloom-bits-per-key"]
+option=bloom_bits
+action=increase
+suggested_values=2
+
+[Rule "small-l0-files"]
+conditions=small-l0-files
+suggestions=dec-max-bytes-for-level-base:inc-write-buffer-size
+
+[Condition "small-l0-files"]
+source=OPTIONS
+options=CFOptions.max_bytes_for_level_base:CFOptions.level0_file_num_compaction_trigger:CFOptions.write_buffer_size
+evaluate=int(options[0])>(10*int(options[1])*int(options[2]))
+
+[Rule "decompress-time-long"]
+conditions=decompress-time-long
+suggestions=dec-block-size:inc-block-cache-size:faster-compression-type
+
+[Condition "decompress-time-long"]
+source=TIME_SERIES
+keys=block_decompress_time:block_read_time:block_checksum_time
+behavior=evaluate_expression
+evaluate=(keys[0]/(keys[0]+keys[1]+keys[2]))>0.3
+
+[Suggestion "dec-block-size"]
+option=TableOptions.BlockBasedTable.block_size
+action=decrease
+
+[Suggestion "inc-block-cache-size"]
+option=cache_size
+action=increase
+suggested_values=16000000
+
+[Suggestion "faster-compression-type"]
+option=CFOptions.compression
+action=set
+suggested_values=kLZ4Compression
diff --git a/src/rocksdb/tools/advisor/test/__init__.py b/src/rocksdb/tools/advisor/test/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/__init__.py
diff --git a/src/rocksdb/tools/advisor/test/input_files/LOG-0 b/src/rocksdb/tools/advisor/test/input_files/LOG-0
new file mode 100644
index 00000000..3c9d5164
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/input_files/LOG-0
@@ -0,0 +1,30 @@
+2018/05/25-14:30:05.601692 7f82bd676200 RocksDB version: 5.14.0
+2018/05/25-14:30:07.626719 7f82ba72e700 (Original Log Time 2018/05/25-14:30:07.621966) [db/db_impl_compaction_flush.cc:1424] Calling FlushMemTableToOutputFile with column family [default], flush slots available 1, compaction slots available 1, flush slots scheduled 1, compaction slots scheduled 0
+2018/05/25-14:30:07.626725 7f82ba72e700 [db/flush_job.cc:301] [default] [JOB 3] Flushing memtable with next log file: 8
+2018/05/25-14:30:07.626738 7f82ba72e700 EVENT_LOG_v1 {"time_micros": 1527283807626732, "job": 3, "event": "flush_started", "num_memtables": 1, "num_entries": 28018, "num_deletes": 0, "memory_usage": 4065512, "flush_reason": "Write Buffer Full"}
+2018/05/25-14:30:07.626740 7f82ba72e700 [db/flush_job.cc:331] [default] [JOB 3] Level-0 flush table #10: started
+2018/05/25-14:30:07.764232 7f82b2f20700 [db/db_impl_write.cc:1373] [default] New memtable created with log file: #11. Immutable memtables: 1.
+2018/05/25-14:30:07.764240 7f82b2f20700 [WARN] [db/column_family.cc:743] [default] Stopping writes because we have 2 immutable memtables (waiting for flush), max_write_buffer_number is set to 2
+2018/05/23-11:53:12.800143 7f9f36b40700 [WARN] [db/column_family.cc:799] [default] Stalling writes because we have 4 level-0 files rate 39886
+2018/05/23-11:53:12.800143 7f9f36b40700 [WARN] [db/column_family.cc:799] [default] Stopping writes because we have 4 level-0 files rate 39886
+2018/05/25-14:30:09.398302 7f82ba72e700 EVENT_LOG_v1 {"time_micros": 1527283809398276, "cf_name": "default", "job": 3, "event": "table_file_creation", "file_number": 10, "file_size": 1890434, "table_properties": {"data_size": 1876749, "index_size": 23346, "filter_size": 0, "raw_key_size": 663120, "raw_average_key_size": 24, "raw_value_size": 2763000, "raw_average_value_size": 100, "num_data_blocks": 838, "num_entries": 27630, "filter_policy_name": "", "kDeletedKeys": "0", "kMergeOperands": "0"}}
+2018/05/25-14:30:09.398351 7f82ba72e700 [db/flush_job.cc:371] [default] [JOB 3] Level-0 flush table #10: 1890434 bytes OK
+2018/05/25-14:30:25.491635 7f82ba72e700 [db/flush_job.cc:331] [default] [JOB 10] Level-0 flush table #23: started
+2018/05/25-14:30:25.643618 7f82b2f20700 [db/db_impl_write.cc:1373] [default] New memtable created with log file: #24. Immutable memtables: 1.
+2018/05/25-14:30:25.643633 7f82b2f20700 [WARN] [db/column_family.cc:743] [default] Stopping writes because we have 2 immutable memtables (waiting for flush), max_write_buffer_number is set to 2
+2018/05/25-14:30:27.288181 7f82ba72e700 EVENT_LOG_v1 {"time_micros": 1527283827288158, "cf_name": "default", "job": 10, "event": "table_file_creation", "file_number": 23, "file_size": 1893200, "table_properties": {"data_size": 1879460, "index_size": 23340, "filter_size": 0, "raw_key_size": 663360, "raw_average_key_size": 24, "raw_value_size": 2764000, "raw_average_value_size": 100, "num_data_blocks": 838, "num_entries": 27640, "filter_policy_name": "", "kDeletedKeys": "0", "kMergeOperands": "0"}}
+2018/05/25-14:30:27.288210 7f82ba72e700 [db/flush_job.cc:371] [default] [JOB 10] Level-0 flush table #23: 1893200 bytes OK
+2018/05/25-14:30:27.289353 7f82ba72e700 [WARN] [db/column_family.cc:764] [default] Stalling writes because of estimated pending compaction bytes 14410584
+2018/05/25-14:30:27.289390 7f82ba72e700 (Original Log Time 2018/05/25-14:30:27.288829) [db/memtable_list.cc:377] [default] Level-0 commit table #23 started
+2018/05/25-14:30:27.289393 7f82ba72e700 (Original Log Time 2018/05/25-14:30:27.289332) [db/memtable_list.cc:409] [default] Level-0 commit table #23: memtable #1 done
+2018/05/25-14:34:21.047206 7f82ba72e700 EVENT_LOG_v1 {"time_micros": 1527284061047181, "cf_name": "default", "job": 44, "event": "table_file_creation", "file_number": 84, "file_size": 1890780, "table_properties": {"data_size": 1877100, "index_size": 23309, "filter_size": 0, "raw_key_size": 662808, "raw_average_key_size": 24, "raw_value_size": 2761700, "raw_average_value_size": 100, "num_data_blocks": 837, "num_entries": 27617, "filter_policy_name": "", "kDeletedKeys": "0", "kMergeOperands": "0"}}
+2018/05/25-14:34:21.047233 7f82ba72e700 [db/flush_job.cc:371] [default] [JOB 44] Level-0 flush table #84: 1890780 bytes OK
+2018/05/25-14:34:21.048017 7f82ba72e700 (Original Log Time 2018/05/25-14:34:21.048005) EVENT_LOG_v1 {"time_micros": 1527284061047997, "job": 44, "event": "flush_finished", "output_compression": "Snappy", "lsm_state": [2, 1, 0, 0, 0, 0, 0], "immutable_memtables": 1}
+2018/05/25-14:34:21.048592 7f82bd676200 [DEBUG] [db/db_impl_files.cc:261] [JOB 45] Delete /tmp/rocksdbtest-155919/dbbench/000084.sst type=2 #84 -- OK
+2018/05/25-14:34:21.048603 7f82bd676200 EVENT_LOG_v1 {"time_micros": 1527284061048600, "job": 45, "event": "table_file_deletion", "file_number": 84}
+2018/05/25-14:34:21.048981 7f82bd676200 [db/db_impl.cc:398] Shutdown complete
+2018/05/25-14:34:21.049000 7f82bd676200 [db/db_impl.cc:563] [col-fam-A] random log message for testing
+2018/05/25-14:34:21.049010 7f82bd676200 [db/db_impl.cc:234] [col-fam-B] log continuing on next line
+remaining part of the log
+2018/05/25-14:34:21.049020 7f82bd676200 [db/db_impl.cc:653] [col-fam-A] another random log message
+2018/05/25-14:34:21.049025 7f82bd676200 [db/db_impl.cc:331] [unknown] random log message no column family
diff --git a/src/rocksdb/tools/advisor/test/input_files/LOG-1 b/src/rocksdb/tools/advisor/test/input_files/LOG-1
new file mode 100644
index 00000000..b163f9a9
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/input_files/LOG-1
@@ -0,0 +1,25 @@
+2018/05/25-14:30:05.601692 7f82bd676200 RocksDB version: 5.14.0
+2018/05/25-14:30:07.626719 7f82ba72e700 (Original Log Time 2018/05/25-14:30:07.621966) [db/db_impl_compaction_flush.cc:1424] Calling FlushMemTableToOutputFile with column family [default], flush slots available 1, compaction slots available 1, flush slots scheduled 1, compaction slots scheduled 0
+2018/05/25-14:30:07.626725 7f82ba72e700 [db/flush_job.cc:301] [default] [JOB 3] Flushing memtable with next log file: 8
+2018/05/25-14:30:07.626738 7f82ba72e700 EVENT_LOG_v1 {"time_micros": 1527283807626732, "job": 3, "event": "flush_started", "num_memtables": 1, "num_entries": 28018, "num_deletes": 0, "memory_usage": 4065512, "flush_reason": "Write Buffer Full"}
+2018/05/25-14:30:07.626740 7f82ba72e700 [db/flush_job.cc:331] [default] [JOB 3] Level-0 flush table #10: started
+2018/05/25-14:30:07.764232 7f82b2f20700 [db/db_impl_write.cc:1373] [default] New memtable created with log file: #11. Immutable memtables: 1.
+2018/05/25-14:30:07.764240 7f82b2f20700 [WARN] [db/column_family.cc:743] [default] Stopping writes because we have 2 immutable memtables (waiting for flush), max_write_buffer_number is set to 2
+2018/05/23-11:53:12.800143 7f9f36b40700 [WARN] [db/column_family.cc:799] [default] Stalling writes because we have 4 level-0 files rate 39886
+2018/05/23-11:53:12.800143 7f9f36b40700 [WARN] [db/column_family.cc:799] [default] Stopping writes because we have 4 level-0 files rate 39886
+2018/05/25-14:30:09.398302 7f82ba72e700 EVENT_LOG_v1 {"time_micros": 1527283809398276, "cf_name": "default", "job": 3, "event": "table_file_creation", "file_number": 10, "file_size": 1890434, "table_properties": {"data_size": 1876749, "index_size": 23346, "filter_size": 0, "raw_key_size": 663120, "raw_average_key_size": 24, "raw_value_size": 2763000, "raw_average_value_size": 100, "num_data_blocks": 838, "num_entries": 27630, "filter_policy_name": "", "kDeletedKeys": "0", "kMergeOperands": "0"}}
+2018/05/25-14:30:09.398351 7f82ba72e700 [db/flush_job.cc:371] [default] [JOB 3] Level-0 flush table #10: 1890434 bytes OK
+2018/05/25-14:30:25.491635 7f82ba72e700 [db/flush_job.cc:331] [default] [JOB 10] Level-0 flush table #23: started
+2018/05/25-14:30:25.643618 7f82b2f20700 [db/db_impl_write.cc:1373] [default] New memtable created with log file: #24. Immutable memtables: 1.
+2018/05/25-14:30:25.643633 7f82b2f20700 [WARN] [db/column_family.cc:743] [default] Stopping writes because we have 2 immutable memtables (waiting for flush), max_write_buffer_number is set to 2
+2018/05/25-14:30:27.288181 7f82ba72e700 EVENT_LOG_v1 {"time_micros": 1527283827288158, "cf_name": "default", "job": 10, "event": "table_file_creation", "file_number": 23, "file_size": 1893200, "table_properties": {"data_size": 1879460, "index_size": 23340, "filter_size": 0, "raw_key_size": 663360, "raw_average_key_size": 24, "raw_value_size": 2764000, "raw_average_value_size": 100, "num_data_blocks": 838, "num_entries": 27640, "filter_policy_name": "", "kDeletedKeys": "0", "kMergeOperands": "0"}}
+2018/05/25-14:30:27.288210 7f82ba72e700 [db/flush_job.cc:371] [default] [JOB 10] Level-0 flush table #23: 1893200 bytes OK
+2018/05/25-14:30:27.289353 7f82ba72e700 [WARN] [db/column_family.cc:764] [default] Stopping writes because of estimated pending compaction bytes 14410584
+2018/05/25-14:30:27.289390 7f82ba72e700 (Original Log Time 2018/05/25-14:30:27.288829) [db/memtable_list.cc:377] [default] Level-0 commit table #23 started
+2018/05/25-14:30:27.289393 7f82ba72e700 (Original Log Time 2018/05/25-14:30:27.289332) [db/memtable_list.cc:409] [default] Level-0 commit table #23: memtable #1 done
+2018/05/25-14:34:21.047206 7f82ba72e700 EVENT_LOG_v1 {"time_micros": 1527284061047181, "cf_name": "default", "job": 44, "event": "table_file_creation", "file_number": 84, "file_size": 1890780, "table_properties": {"data_size": 1877100, "index_size": 23309, "filter_size": 0, "raw_key_size": 662808, "raw_average_key_size": 24, "raw_value_size": 2761700, "raw_average_value_size": 100, "num_data_blocks": 837, "num_entries": 27617, "filter_policy_name": "", "kDeletedKeys": "0", "kMergeOperands": "0"}}
+2018/05/25-14:34:21.047233 7f82ba72e700 [db/flush_job.cc:371] [default] [JOB 44] Level-0 flush table #84: 1890780 bytes OK
+2018/05/25-14:34:21.048017 7f82ba72e700 (Original Log Time 2018/05/25-14:34:21.048005) EVENT_LOG_v1 {"time_micros": 1527284061047997, "job": 44, "event": "flush_finished", "output_compression": "Snappy", "lsm_state": [2, 1, 0, 0, 0, 0, 0], "immutable_memtables": 1}
+2018/05/25-14:34:21.048592 7f82bd676200 [DEBUG] [db/db_impl_files.cc:261] [JOB 45] Delete /tmp/rocksdbtest-155919/dbbench/000084.sst type=2 #84 -- OK
+2018/05/25-14:34:21.048603 7f82bd676200 EVENT_LOG_v1 {"time_micros": 1527284061048600, "job": 45, "event": "table_file_deletion", "file_number": 84}
+2018/05/25-14:34:21.048981 7f82bd676200 [db/db_impl.cc:398] Shutdown complete
diff --git a/src/rocksdb/tools/advisor/test/input_files/OPTIONS-000005 b/src/rocksdb/tools/advisor/test/input_files/OPTIONS-000005
new file mode 100644
index 00000000..009edb04
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/input_files/OPTIONS-000005
@@ -0,0 +1,49 @@
+# This is a RocksDB option file.
+#
+# For detailed file format spec, please refer to the example file
+# in examples/rocksdb_option_file_example.ini
+#
+
+[Version]
+  rocksdb_version=5.14.0
+  options_file_version=1.1
+
+[DBOptions]
+  manual_wal_flush=false
+  allow_ingest_behind=false
+  db_write_buffer_size=0
+  db_log_dir=
+  random_access_max_buffer_size=1048576
+
+[CFOptions "default"]
+  ttl=0
+  max_bytes_for_level_base=268435456
+  max_bytes_for_level_multiplier=10.000000
+  level0_file_num_compaction_trigger=4
+  level0_stop_writes_trigger=36
+  write_buffer_size=4194000
+  min_write_buffer_number_to_merge=1
+  num_levels=7
+  compaction_filter_factory=nullptr
+  compaction_style=kCompactionStyleLevel
+
+[TableOptions/BlockBasedTable "default"]
+  block_align=false
+  index_type=kBinarySearch
+
+[CFOptions "col_fam_A"]
+ttl=0
+max_bytes_for_level_base=268435456
+max_bytes_for_level_multiplier=10.000000
+level0_file_num_compaction_trigger=5
+level0_stop_writes_trigger=36
+write_buffer_size=1024000
+min_write_buffer_number_to_merge=1
+num_levels=5
+compaction_filter_factory=nullptr
+compaction_style=kCompactionStyleLevel
+
+[TableOptions/BlockBasedTable "col_fam_A"]
+block_align=true
+block_restart_interval=16
+index_type=kBinarySearch
diff --git a/src/rocksdb/tools/advisor/test/input_files/log_stats_parser_keys_ts b/src/rocksdb/tools/advisor/test/input_files/log_stats_parser_keys_ts
new file mode 100644
index 00000000..e8ade9e3
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/input_files/log_stats_parser_keys_ts
@@ -0,0 +1,3 @@
+rocksdb.number.block.decompressed.count: 1530896335 88.0, 1530896361 788338.0, 1530896387 1539256.0, 1530896414 2255696.0, 1530896440 3009325.0, 1530896466 3767183.0, 1530896492 4529775.0, 1530896518 5297809.0, 1530896545 6033802.0, 1530896570 6794129.0
+rocksdb.db.get.micros.p50: 1530896335 295.5, 1530896361 16.561841, 1530896387 16.20677, 1530896414 16.31508, 1530896440 16.346602, 1530896466 16.284669, 1530896492 16.16005, 1530896518 16.069096, 1530896545 16.028746, 1530896570 15.9638
+rocksdb.manifest.file.sync.micros.p99: 1530896335 649.0, 1530896361 835.0, 1530896387 1435.0, 1530896414 9938.0, 1530896440 9938.0, 1530896466 9938.0, 1530896492 9938.0, 1530896518 1882.0, 1530896545 1837.0, 1530896570 1792.0
diff --git a/src/rocksdb/tools/advisor/test/input_files/rules_err1.ini b/src/rocksdb/tools/advisor/test/input_files/rules_err1.ini
new file mode 100644
index 00000000..23be55dd
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/input_files/rules_err1.ini
@@ -0,0 +1,56 @@
+[Rule "missing-suggestions"]
+suggestions=
+conditions=missing-source
+
+[Condition "normal-rule"]
+source=LOG
+regex=Stopping writes because we have \d+ immutable memtables \(waiting for flush\), max_write_buffer_number is set to \d+
+
+[Suggestion "inc-bg-flush"]
+option=DBOptions.max_background_flushes
+action=increase
+
+[Suggestion "inc-write-buffer"]
+option=CFOptions.max_write_buffer_number
+action=increase
+
+[Rule "missing-conditions"]
+conditions=
+suggestions=missing-description
+
+[Condition "missing-options"]
+source=OPTIONS
+options=
+evaluate=int(options[0])*int(options[1])-int(options[2])<(-251659456)  # should evaluate to a boolean
+
+[Rule "missing-expression"]
+conditions=missing-expression
+suggestions=missing-description
+
+[Condition "missing-expression"]
+source=OPTIONS
+options=CFOptions.level0_file_num_compaction_trigger:CFOptions.write_buffer_size:CFOptions.max_bytes_for_level_base
+evaluate=
+
+[Suggestion "missing-description"]
+description=
+
+[Rule "stop-too-many-L0"]
+suggestions=inc-max-bg-compactions:missing-action:inc-l0-stop-writes-trigger
+conditions=missing-regex
+
+[Condition "missing-regex"]
+source=LOG
+regex=
+
+[Suggestion "missing-option"]
+option=
+action=increase
+
+[Suggestion "normal-suggestion"]
+option=CFOptions.write_buffer_size
+action=increase
+
+[Suggestion "inc-l0-stop-writes-trigger"]
+option=CFOptions.level0_stop_writes_trigger
+action=increase
diff --git a/src/rocksdb/tools/advisor/test/input_files/rules_err2.ini b/src/rocksdb/tools/advisor/test/input_files/rules_err2.ini
new file mode 100644
index 00000000..bce21dba
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/input_files/rules_err2.ini
@@ -0,0 +1,15 @@
+[Rule "normal-rule"]
+suggestions=inc-bg-flush:inc-write-buffer
+conditions=missing-source
+
+[Condition "missing-source"]
+source=
+regex=Stopping writes because we have \d+ immutable memtables \(waiting for flush\), max_write_buffer_number is set to \d+
+
+[Suggestion "inc-bg-flush"]
+option=DBOptions.max_background_flushes
+action=increase
+
+[Suggestion "inc-write-buffer"]
+option=CFOptions.max_write_buffer_number
+action=increase
diff --git a/src/rocksdb/tools/advisor/test/input_files/rules_err3.ini b/src/rocksdb/tools/advisor/test/input_files/rules_err3.ini
new file mode 100644
index 00000000..73c06e46
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/input_files/rules_err3.ini
@@ -0,0 +1,15 @@
+[Rule "normal-rule"]
+suggestions=missing-action:inc-write-buffer
+conditions=missing-source
+
+[Condition "normal-condition"]
+source=LOG
+regex=Stopping writes because we have \d+ immutable memtables \(waiting for flush\), max_write_buffer_number is set to \d+
+
+[Suggestion "missing-action"]
+option=DBOptions.max_background_flushes
+action=
+
+[Suggestion "inc-write-buffer"]
+option=CFOptions.max_write_buffer_number
+action=increase
diff --git a/src/rocksdb/tools/advisor/test/input_files/rules_err4.ini b/src/rocksdb/tools/advisor/test/input_files/rules_err4.ini
new file mode 100644
index 00000000..4d4aa3c7
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/input_files/rules_err4.ini
@@ -0,0 +1,15 @@
+[Rule "normal-rule"]
+suggestions=inc-bg-flush
+conditions=missing-source
+
+[Condition "normal-condition"]
+source=LOG
+regex=Stopping writes because we have \d+ immutable memtables \(waiting for flush\), max_write_buffer_number is set to \d+
+
+[Suggestion "inc-bg-flush"]
+option=DBOptions.max_background_flushes
+action=increase
+
+[Suggestion]  # missing section name
+option=CFOptions.max_write_buffer_number
+action=increase
diff --git a/src/rocksdb/tools/advisor/test/input_files/test_rules.ini b/src/rocksdb/tools/advisor/test/input_files/test_rules.ini
new file mode 100644
index 00000000..97b9374f
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/input_files/test_rules.ini
@@ -0,0 +1,47 @@
+[Rule "single-condition-false"]
+suggestions=inc-bg-flush:inc-write-buffer
+conditions=log-4-false
+
+[Rule "multiple-conds-true"]
+suggestions=inc-write-buffer
+conditions=log-1-true:log-2-true:log-3-true
+
+[Rule "multiple-conds-one-false"]
+suggestions=inc-bg-flush
+conditions=log-1-true:log-4-false:log-3-true
+
+[Rule "multiple-conds-all-false"]
+suggestions=l0-l1-ratio-health-check
+conditions=log-4-false:options-1-false
+
+[Condition "log-1-true"]
+source=LOG
+regex=Stopping writes because we have \d+ immutable memtables \(waiting for flush\), max_write_buffer_number is set to \d+
+
+[Condition "log-2-true"]
+source=LOG
+regex=Stalling writes because we have \d+ level-0 files
+
+[Condition "log-3-true"]
+source=LOG
+regex=Stopping writes because we have \d+ level-0 files
+
+[Condition "log-4-false"]
+source=LOG
+regex=Stalling writes because of estimated pending compaction bytes \d+
+
+[Condition "options-1-false"]
+source=OPTIONS
+options=CFOptions.level0_file_num_compaction_trigger:CFOptions.write_buffer_size:DBOptions.random_access_max_buffer_size
+evaluate=int(options[0])*int(options[1])-int(options[2])<0  # should evaluate to a boolean
+
+[Suggestion "inc-bg-flush"]
+option=DBOptions.max_background_flushes
+action=increase
+
+[Suggestion "inc-write-buffer"]
+option=CFOptions.max_write_buffer_number
+action=increase
+
+[Suggestion "l0-l1-ratio-health-check"]
+description='modify options such that (level0_file_num_compaction_trigger * write_buffer_size - max_bytes_for_level_base < 5) is satisfied'
diff --git a/src/rocksdb/tools/advisor/test/input_files/triggered_rules.ini b/src/rocksdb/tools/advisor/test/input_files/triggered_rules.ini
new file mode 100644
index 00000000..83b96da2
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/input_files/triggered_rules.ini
@@ -0,0 +1,83 @@
+[Rule "stall-too-many-memtables"]
+suggestions=inc-bg-flush:inc-write-buffer
+conditions=stall-too-many-memtables
+
+[Condition "stall-too-many-memtables"]
+source=LOG
+regex=Stopping writes because we have \d+ immutable memtables \(waiting for flush\), max_write_buffer_number is set to \d+
+
+[Rule "stall-too-many-L0"]
+suggestions=inc-max-subcompactions:inc-max-bg-compactions:inc-write-buffer-size:dec-max-bytes-for-level-base:inc-l0-slowdown-writes-trigger
+conditions=stall-too-many-L0
+
+[Condition "stall-too-many-L0"]
+source=LOG
+regex=Stalling writes because we have \d+ level-0 files
+
+[Rule "stop-too-many-L0"]
+suggestions=inc-max-bg-compactions:inc-write-buffer-size:inc-l0-stop-writes-trigger
+conditions=stop-too-many-L0
+
+[Condition "stop-too-many-L0"]
+source=LOG
+regex=Stopping writes because we have \d+ level-0 files
+
+[Rule "stall-too-many-compaction-bytes"]
+suggestions=inc-max-bg-compactions:inc-write-buffer-size:inc-hard-pending-compaction-bytes-limit:inc-soft-pending-compaction-bytes-limit
+conditions=stall-too-many-compaction-bytes
+
+[Condition "stall-too-many-compaction-bytes"]
+source=LOG
+regex=Stalling writes because of estimated pending compaction bytes \d+
+
+[Suggestion "inc-bg-flush"]
+option=DBOptions.max_background_flushes
+action=increase
+
+[Suggestion "inc-write-buffer"]
+option=CFOptions.max_write_buffer_number
+action=increase
+
+[Suggestion "inc-max-subcompactions"]
+option=DBOptions.max_subcompactions
+action=increase
+
+[Suggestion "inc-max-bg-compactions"]
+option=DBOptions.max_background_compactions
+action=increase
+
+[Suggestion "inc-write-buffer-size"]
+option=CFOptions.write_buffer_size
+action=increase
+
+[Suggestion "dec-max-bytes-for-level-base"]
+option=CFOptions.max_bytes_for_level_base
+action=decrease
+
+[Suggestion "inc-l0-slowdown-writes-trigger"]
+option=CFOptions.level0_slowdown_writes_trigger
+action=increase
+
+[Suggestion "inc-l0-stop-writes-trigger"]
+option=CFOptions.level0_stop_writes_trigger
+action=increase
+
+[Suggestion "inc-hard-pending-compaction-bytes-limit"]
+option=CFOptions.hard_pending_compaction_bytes_limit
+action=increase
+
+[Suggestion "inc-soft-pending-compaction-bytes-limit"]
+option=CFOptions.soft_pending_compaction_bytes_limit
+action=increase
+
+[Rule "level0-level1-ratio"]
+conditions=level0-level1-ratio
+suggestions=l0-l1-ratio-health-check
+
+[Condition "level0-level1-ratio"]
+source=OPTIONS
+options=CFOptions.level0_file_num_compaction_trigger:CFOptions.write_buffer_size:CFOptions.max_bytes_for_level_base
+evaluate=int(options[0])*int(options[1])-int(options[2])>=-268173312  # should evaluate to a boolean, condition triggered if evaluates to true
+
+[Suggestion "l0-l1-ratio-health-check"]
+description='modify options such that (level0_file_num_compaction_trigger * write_buffer_size - max_bytes_for_level_base < -268173312) is satisfied'
diff --git a/src/rocksdb/tools/advisor/test/test_db_bench_runner.py b/src/rocksdb/tools/advisor/test/test_db_bench_runner.py
new file mode 100644
index 00000000..1c4f77d5
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/test_db_bench_runner.py
@@ -0,0 +1,147 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from advisor.db_bench_runner import DBBenchRunner
+from advisor.db_log_parser import NO_COL_FAMILY, DataSource
+from advisor.db_options_parser import DatabaseOptions
+import os
+import unittest
+
+
+class TestDBBenchRunnerMethods(unittest.TestCase):
+    def setUp(self):
+        self.pos_args = [
+            './../../db_bench',
+            'overwrite',
+            'use_existing_db=true',
+            'duration=10'
+        ]
+        self.bench_runner = DBBenchRunner(self.pos_args)
+        this_path = os.path.abspath(os.path.dirname(__file__))
+        options_path = os.path.join(this_path, 'input_files/OPTIONS-000005')
+        self.db_options = DatabaseOptions(options_path)
+
+    def test_setup(self):
+        self.assertEqual(self.bench_runner.db_bench_binary, self.pos_args[0])
+        self.assertEqual(self.bench_runner.benchmark, self.pos_args[1])
+        self.assertSetEqual(
+            set(self.bench_runner.db_bench_args), set(self.pos_args[2:])
+        )
+
+    def test_get_info_log_file_name(self):
+        log_file_name = DBBenchRunner.get_info_log_file_name(
+            None, 'random_path'
+        )
+        self.assertEqual(log_file_name, 'LOG')
+
+        log_file_name = DBBenchRunner.get_info_log_file_name(
+            '/dev/shm/', '/tmp/rocksdbtest-155919/dbbench/'
+        )
+        self.assertEqual(log_file_name, 'tmp_rocksdbtest-155919_dbbench_LOG')
+
+    def test_get_opt_args_str(self):
+        misc_opt_dict = {'bloom_bits': 2, 'empty_opt': None, 'rate_limiter': 3}
+        optional_args_str = DBBenchRunner.get_opt_args_str(misc_opt_dict)
+        self.assertEqual(optional_args_str, ' --bloom_bits=2 --rate_limiter=3')
+
+    def test_get_log_options(self):
+        db_path = '/tmp/rocksdb-155919/dbbench'
+        # when db_log_dir is present in the db_options
+        update_dict = {
+            'DBOptions.db_log_dir': {NO_COL_FAMILY: '/dev/shm'},
+            'DBOptions.stats_dump_period_sec': {NO_COL_FAMILY: '20'}
+        }
+        self.db_options.update_options(update_dict)
+        log_file_prefix, stats_freq = self.bench_runner.get_log_options(
+            self.db_options, db_path
+        )
+        self.assertEqual(
+            log_file_prefix, '/dev/shm/tmp_rocksdb-155919_dbbench_LOG'
+        )
+        self.assertEqual(stats_freq, 20)
+
+        update_dict = {
+            'DBOptions.db_log_dir': {NO_COL_FAMILY: None},
+            'DBOptions.stats_dump_period_sec': {NO_COL_FAMILY: '30'}
+        }
+        self.db_options.update_options(update_dict)
+        log_file_prefix, stats_freq = self.bench_runner.get_log_options(
+            self.db_options, db_path
+        )
+        self.assertEqual(log_file_prefix, '/tmp/rocksdb-155919/dbbench/LOG')
+        self.assertEqual(stats_freq, 30)
+
+    def test_build_experiment_command(self):
+        # add some misc_options to db_options
+        update_dict = {
+            'bloom_bits': {NO_COL_FAMILY: 2},
+            'rate_limiter_bytes_per_sec': {NO_COL_FAMILY: 128000000}
+        }
+        self.db_options.update_options(update_dict)
+        db_path = '/dev/shm'
+        experiment_command = self.bench_runner._build_experiment_command(
+            self.db_options, db_path
+        )
+        opt_args_str = DBBenchRunner.get_opt_args_str(
+            self.db_options.get_misc_options()
+        )
+        opt_args_str += (
+            ' --options_file=' +
+            self.db_options.generate_options_config('12345')
+        )
+        for arg in self.pos_args[2:]:
+            opt_args_str += (' --' + arg)
+        expected_command = (
+            self.pos_args[0] + ' --benchmarks=' + self.pos_args[1] +
+            ' --statistics --perf_level=3 --db=' + db_path + opt_args_str
+        )
+        self.assertEqual(experiment_command, expected_command)
+
+
+class TestDBBenchRunner(unittest.TestCase):
+    def setUp(self):
+        # Note: the db_bench binary should be present in the rocksdb/ directory
+        self.pos_args = [
+            './../../db_bench',
+            'overwrite',
+            'use_existing_db=true',
+            'duration=20'
+        ]
+        self.bench_runner = DBBenchRunner(self.pos_args)
+        this_path = os.path.abspath(os.path.dirname(__file__))
+        options_path = os.path.join(this_path, 'input_files/OPTIONS-000005')
+        self.db_options = DatabaseOptions(options_path)
+
+    def test_experiment_output(self):
+        update_dict = {'bloom_bits': {NO_COL_FAMILY: 2}}
+        self.db_options.update_options(update_dict)
+        db_path = '/dev/shm'
+        data_sources, throughput = self.bench_runner.run_experiment(
+            self.db_options, db_path
+        )
+        self.assertEqual(
+            data_sources[DataSource.Type.DB_OPTIONS][0].type,
+            DataSource.Type.DB_OPTIONS
+        )
+        self.assertEqual(
+            data_sources[DataSource.Type.LOG][0].type,
+            DataSource.Type.LOG
+        )
+        self.assertEqual(len(data_sources[DataSource.Type.TIME_SERIES]), 2)
+        self.assertEqual(
+            data_sources[DataSource.Type.TIME_SERIES][0].type,
+            DataSource.Type.TIME_SERIES
+        )
+        self.assertEqual(
+            data_sources[DataSource.Type.TIME_SERIES][1].type,
+            DataSource.Type.TIME_SERIES
+        )
+        self.assertEqual(
+            data_sources[DataSource.Type.TIME_SERIES][1].stats_freq_sec, 0
+        )
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/src/rocksdb/tools/advisor/test/test_db_log_parser.py b/src/rocksdb/tools/advisor/test/test_db_log_parser.py
new file mode 100644
index 00000000..b7043043
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/test_db_log_parser.py
@@ -0,0 +1,103 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from advisor.db_log_parser import DatabaseLogs, Log, NO_COL_FAMILY
+from advisor.rule_parser import Condition, LogCondition
+import os
+import unittest
+
+
+class TestLog(unittest.TestCase):
+    def setUp(self):
+        self.column_families = ['default', 'col_fam_A']
+
+    def test_get_column_family(self):
+        test_log = (
+            "2018/05/25-14:34:21.047233 7f82ba72e700 [db/flush_job.cc:371] " +
+            "[col_fam_A] [JOB 44] Level-0 flush table #84: 1890780 bytes OK"
+        )
+        db_log = Log(test_log, self.column_families)
+        self.assertEqual('col_fam_A', db_log.get_column_family())
+
+        test_log = (
+            "2018/05/25-14:34:21.047233 7f82ba72e700 [db/flush_job.cc:371] " +
+            "[JOB 44] Level-0 flush table #84: 1890780 bytes OK"
+        )
+        db_log = Log(test_log, self.column_families)
+        db_log.append_message('[default] some remaining part of log')
+        self.assertEqual(NO_COL_FAMILY, db_log.get_column_family())
+
+    def test_get_methods(self):
+        hr_time = "2018/05/25-14:30:25.491635"
+        context = "7f82ba72e700"
+        message = (
+            "[db/flush_job.cc:331] [default] [JOB 10] Level-0 flush table " +
+            "#23: started"
+        )
+        test_log = hr_time + " " + context + " " + message
+        db_log = Log(test_log, self.column_families)
+        self.assertEqual(db_log.get_message(), message)
+        remaining_message = "[col_fam_A] some more logs"
+        db_log.append_message(remaining_message)
+        self.assertEqual(
+            db_log.get_human_readable_time(), "2018/05/25-14:30:25.491635"
+        )
+        self.assertEqual(db_log.get_context(), "7f82ba72e700")
+        self.assertEqual(db_log.get_timestamp(), 1527258625)
+        self.assertEqual(
+            db_log.get_message(), str(message + '\n' + remaining_message)
+        )
+
+    def test_is_new_log(self):
+        new_log = "2018/05/25-14:34:21.047233 context random new log"
+        remaining_log = "2018/05/25 not really a new log"
+        self.assertTrue(Log.is_new_log(new_log))
+        self.assertFalse(Log.is_new_log(remaining_log))
+
+
+class TestDatabaseLogs(unittest.TestCase):
+    def test_check_and_trigger_conditions(self):
+        this_path = os.path.abspath(os.path.dirname(__file__))
+        logs_path_prefix = os.path.join(this_path, 'input_files/LOG-0')
+        column_families = ['default', 'col-fam-A', 'col-fam-B']
+        db_logs = DatabaseLogs(logs_path_prefix, column_families)
+        # matches, has 2 col_fams
+        condition1 = LogCondition.create(Condition('cond-A'))
+        condition1.set_parameter('regex', 'random log message')
+        # matches, multiple lines message
+        condition2 = LogCondition.create(Condition('cond-B'))
+        condition2.set_parameter('regex', 'continuing on next line')
+        # does not match
+        condition3 = LogCondition.create(Condition('cond-C'))
+        condition3.set_parameter('regex', 'this should match no log')
+        db_logs.check_and_trigger_conditions(
+            [condition1, condition2, condition3]
+        )
+        cond1_trigger = condition1.get_trigger()
+        self.assertEqual(2, len(cond1_trigger.keys()))
+        self.assertSetEqual(
+            {'col-fam-A', NO_COL_FAMILY}, set(cond1_trigger.keys())
+        )
+        self.assertEqual(2, len(cond1_trigger['col-fam-A']))
+        messages = [
+            "[db/db_impl.cc:563] [col-fam-A] random log message for testing",
+            "[db/db_impl.cc:653] [col-fam-A] another random log message"
+        ]
+        self.assertIn(cond1_trigger['col-fam-A'][0].get_message(), messages)
+        self.assertIn(cond1_trigger['col-fam-A'][1].get_message(), messages)
+        self.assertEqual(1, len(cond1_trigger[NO_COL_FAMILY]))
+        self.assertEqual(
+            cond1_trigger[NO_COL_FAMILY][0].get_message(),
+            "[db/db_impl.cc:331] [unknown] random log message no column family"
+        )
+        cond2_trigger = condition2.get_trigger()
+        self.assertEqual(['col-fam-B'], list(cond2_trigger.keys()))
+        self.assertEqual(1, len(cond2_trigger['col-fam-B']))
+        self.assertEqual(
+            cond2_trigger['col-fam-B'][0].get_message(),
+            "[db/db_impl.cc:234] [col-fam-B] log continuing on next line\n" +
+            "remaining part of the log"
+        )
+        self.assertIsNone(condition3.get_trigger())
diff --git a/src/rocksdb/tools/advisor/test/test_db_options_parser.py b/src/rocksdb/tools/advisor/test/test_db_options_parser.py
new file mode 100644
index 00000000..d53a9bdb
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/test_db_options_parser.py
@@ -0,0 +1,216 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from advisor.db_log_parser import NO_COL_FAMILY
+from advisor.db_options_parser import DatabaseOptions
+from advisor.rule_parser import Condition, OptionCondition
+import os
+import unittest
+
+
+class TestDatabaseOptions(unittest.TestCase):
+    def setUp(self):
+        self.this_path = os.path.abspath(os.path.dirname(__file__))
+        self.og_options = os.path.join(
+            self.this_path, 'input_files/OPTIONS-000005'
+        )
+        misc_options = [
+            'bloom_bits = 4', 'rate_limiter_bytes_per_sec = 1024000'
+        ]
+        # create the options object
+        self.db_options = DatabaseOptions(self.og_options, misc_options)
+        # perform clean-up before running tests
+        self.generated_options = os.path.join(
+            self.this_path, '../temp/OPTIONS_testing.tmp'
+        )
+        if os.path.isfile(self.generated_options):
+            os.remove(self.generated_options)
+
+    def test_get_options_diff(self):
+        old_opt = {
+            'DBOptions.stats_dump_freq_sec': {NO_COL_FAMILY: '20'},
+            'CFOptions.write_buffer_size': {
+                'default': '1024000',
+                'col_fam_A': '128000',
+                'col_fam_B': '128000000'
+            },
+            'DBOptions.use_fsync': {NO_COL_FAMILY: 'true'},
+            'DBOptions.max_log_file_size': {NO_COL_FAMILY: '128000000'}
+        }
+        new_opt = {
+            'bloom_bits': {NO_COL_FAMILY: '4'},
+            'CFOptions.write_buffer_size': {
+                'default': '128000000',
+                'col_fam_A': '128000',
+                'col_fam_C': '128000000'
+            },
+            'DBOptions.use_fsync': {NO_COL_FAMILY: 'true'},
+            'DBOptions.max_log_file_size': {NO_COL_FAMILY: '0'}
+        }
+        diff = DatabaseOptions.get_options_diff(old_opt, new_opt)
+
+        expected_diff = {
+            'DBOptions.stats_dump_freq_sec': {NO_COL_FAMILY: ('20', None)},
+            'bloom_bits': {NO_COL_FAMILY: (None, '4')},
+            'CFOptions.write_buffer_size': {
+                'default': ('1024000', '128000000'),
+                'col_fam_B': ('128000000', None),
+                'col_fam_C': (None, '128000000')
+            },
+            'DBOptions.max_log_file_size': {NO_COL_FAMILY: ('128000000', '0')}
+        }
+        self.assertDictEqual(diff, expected_diff)
+
+    def test_is_misc_option(self):
+        self.assertTrue(DatabaseOptions.is_misc_option('bloom_bits'))
+        self.assertFalse(
+            DatabaseOptions.is_misc_option('DBOptions.stats_dump_freq_sec')
+        )
+
+    def test_set_up(self):
+        options = self.db_options.get_all_options()
+        self.assertEqual(22, len(options.keys()))
+        expected_misc_options = {
+            'bloom_bits': '4', 'rate_limiter_bytes_per_sec': '1024000'
+        }
+        self.assertDictEqual(
+            expected_misc_options, self.db_options.get_misc_options()
+        )
+        self.assertListEqual(
+            ['default', 'col_fam_A'], self.db_options.get_column_families()
+        )
+
+    def test_get_options(self):
+        opt_to_get = [
+            'DBOptions.manual_wal_flush', 'DBOptions.db_write_buffer_size',
+            'bloom_bits', 'CFOptions.compaction_filter_factory',
+            'CFOptions.num_levels', 'rate_limiter_bytes_per_sec',
+            'TableOptions.BlockBasedTable.block_align', 'random_option'
+        ]
+        options = self.db_options.get_options(opt_to_get)
+        expected_options = {
+            'DBOptions.manual_wal_flush': {NO_COL_FAMILY: 'false'},
+            'DBOptions.db_write_buffer_size': {NO_COL_FAMILY: '0'},
+            'bloom_bits': {NO_COL_FAMILY: '4'},
+            'CFOptions.compaction_filter_factory': {
+                'default': 'nullptr', 'col_fam_A': 'nullptr'
+            },
+            'CFOptions.num_levels': {'default': '7', 'col_fam_A': '5'},
+            'rate_limiter_bytes_per_sec': {NO_COL_FAMILY: '1024000'},
+            'TableOptions.BlockBasedTable.block_align': {
+                'default': 'false', 'col_fam_A': 'true'
+            }
+        }
+        self.assertDictEqual(expected_options, options)
+
+    def test_update_options(self):
+        # add new, update old, set old
+        # before updating
+        expected_old_opts = {
+            'DBOptions.db_log_dir': {NO_COL_FAMILY: None},
+            'DBOptions.manual_wal_flush': {NO_COL_FAMILY: 'false'},
+            'bloom_bits': {NO_COL_FAMILY: '4'},
+            'CFOptions.num_levels': {'default': '7', 'col_fam_A': '5'},
+            'TableOptions.BlockBasedTable.block_restart_interval': {
+                'col_fam_A': '16'
+            }
+        }
+        get_opts = list(expected_old_opts.keys())
+        options = self.db_options.get_options(get_opts)
+        self.assertEqual(expected_old_opts, options)
+        # after updating options
+        update_opts = {
+            'DBOptions.db_log_dir': {NO_COL_FAMILY: '/dev/shm'},
+            'DBOptions.manual_wal_flush': {NO_COL_FAMILY: 'true'},
+            'bloom_bits': {NO_COL_FAMILY: '2'},
+            'CFOptions.num_levels': {'col_fam_A': '7'},
+            'TableOptions.BlockBasedTable.block_restart_interval': {
+                'default': '32'
+            },
+            'random_misc_option': {NO_COL_FAMILY: 'something'}
+        }
+        self.db_options.update_options(update_opts)
+        update_opts['CFOptions.num_levels']['default'] = '7'
+        update_opts['TableOptions.BlockBasedTable.block_restart_interval'] = {
+            'default': '32', 'col_fam_A': '16'
+        }
+        get_opts.append('random_misc_option')
+        options = self.db_options.get_options(get_opts)
+        self.assertDictEqual(update_opts, options)
+        expected_misc_options = {
+            'bloom_bits': '2',
+            'rate_limiter_bytes_per_sec': '1024000',
+            'random_misc_option': 'something'
+        }
+        self.assertDictEqual(
+            expected_misc_options, self.db_options.get_misc_options()
+        )
+
+    def test_generate_options_config(self):
+        # make sure file does not exist from before
+        self.assertFalse(os.path.isfile(self.generated_options))
+        self.db_options.generate_options_config('testing')
+        self.assertTrue(os.path.isfile(self.generated_options))
+
+    def test_check_and_trigger_conditions(self):
+        # options only from CFOptions
+        # setup the OptionCondition objects to check and trigger
+        update_dict = {
+            'CFOptions.level0_file_num_compaction_trigger': {'col_fam_A': '4'},
+            'CFOptions.max_bytes_for_level_base': {'col_fam_A': '10'}
+        }
+        self.db_options.update_options(update_dict)
+        cond1 = Condition('opt-cond-1')
+        cond1 = OptionCondition.create(cond1)
+        cond1.set_parameter(
+            'options', [
+                'CFOptions.level0_file_num_compaction_trigger',
+                'TableOptions.BlockBasedTable.block_restart_interval',
+                'CFOptions.max_bytes_for_level_base'
+            ]
+        )
+        cond1.set_parameter(
+            'evaluate',
+            'int(options[0])*int(options[1])-int(options[2])>=0'
+        )
+        # only DBOptions
+        cond2 = Condition('opt-cond-2')
+        cond2 = OptionCondition.create(cond2)
+        cond2.set_parameter(
+            'options', [
+                'DBOptions.db_write_buffer_size',
+                'bloom_bits',
+                'rate_limiter_bytes_per_sec'
+            ]
+        )
+        cond2.set_parameter(
+            'evaluate',
+            '(int(options[2]) * int(options[1]) * int(options[0]))==0'
+        )
+        # mix of CFOptions and DBOptions
+        cond3 = Condition('opt-cond-3')
+        cond3 = OptionCondition.create(cond3)
+        cond3.set_parameter(
+            'options', [
+                'DBOptions.db_write_buffer_size',  # 0
+                'CFOptions.num_levels',  # 5, 7
+                'bloom_bits'  # 4
+            ]
+        )
+        cond3.set_parameter(
+            'evaluate', 'int(options[2])*int(options[0])+int(options[1])>6'
+        )
+        self.db_options.check_and_trigger_conditions([cond1, cond2, cond3])
+
+        cond1_trigger = {'col_fam_A': ['4', '16', '10']}
+        self.assertDictEqual(cond1_trigger, cond1.get_trigger())
+        cond2_trigger = {NO_COL_FAMILY: ['0', '4', '1024000']}
+        self.assertDictEqual(cond2_trigger, cond2.get_trigger())
+        cond3_trigger = {'default': ['0', '7', '4']}
+        self.assertDictEqual(cond3_trigger, cond3.get_trigger())
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/src/rocksdb/tools/advisor/test/test_db_stats_fetcher.py b/src/rocksdb/tools/advisor/test/test_db_stats_fetcher.py
new file mode 100644
index 00000000..afbbe833
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/test_db_stats_fetcher.py
@@ -0,0 +1,126 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+from advisor.db_stats_fetcher import LogStatsParser, DatabasePerfContext
+from advisor.db_timeseries_parser import NO_ENTITY
+from advisor.rule_parser import Condition, TimeSeriesCondition
+import os
+import time
+import unittest
+from unittest.mock import MagicMock
+
+
+class TestLogStatsParser(unittest.TestCase):
+    def setUp(self):
+        this_path = os.path.abspath(os.path.dirname(__file__))
+        stats_file = os.path.join(
+            this_path, 'input_files/log_stats_parser_keys_ts'
+        )
+        # populate the keys_ts dictionary of LogStatsParser
+        self.stats_dict = {NO_ENTITY: {}}
+        with open(stats_file, 'r') as fp:
+            for line in fp:
+                stat_name = line.split(':')[0].strip()
+                self.stats_dict[NO_ENTITY][stat_name] = {}
+                token_list = line.split(':')[1].strip().split(',')
+                for token in token_list:
+                    timestamp = int(token.split()[0])
+                    value = float(token.split()[1])
+                    self.stats_dict[NO_ENTITY][stat_name][timestamp] = value
+        self.log_stats_parser = LogStatsParser('dummy_log_file', 20)
+        self.log_stats_parser.keys_ts = self.stats_dict
+
+    def test_check_and_trigger_conditions_bursty(self):
+        # mock fetch_timeseries() because 'keys_ts' has been pre-populated
+        self.log_stats_parser.fetch_timeseries = MagicMock()
+        # condition: bursty
+        cond1 = Condition('cond-1')
+        cond1 = TimeSeriesCondition.create(cond1)
+        cond1.set_parameter('keys', 'rocksdb.db.get.micros.p50')
+        cond1.set_parameter('behavior', 'bursty')
+        cond1.set_parameter('window_sec', 40)
+        cond1.set_parameter('rate_threshold', 0)
+        self.log_stats_parser.check_and_trigger_conditions([cond1])
+        expected_cond_trigger = {
+            NO_ENTITY: {1530896440: 0.9767546362322214}
+        }
+        self.assertDictEqual(expected_cond_trigger, cond1.get_trigger())
+        # ensure that fetch_timeseries() was called once
+        self.log_stats_parser.fetch_timeseries.assert_called_once()
+
+    def test_check_and_trigger_conditions_eval_agg(self):
+        # mock fetch_timeseries() because 'keys_ts' has been pre-populated
+        self.log_stats_parser.fetch_timeseries = MagicMock()
+        # condition: evaluate_expression
+        cond1 = Condition('cond-1')
+        cond1 = TimeSeriesCondition.create(cond1)
+        cond1.set_parameter('keys', 'rocksdb.db.get.micros.p50')
+        cond1.set_parameter('behavior', 'evaluate_expression')
+        keys = [
+            'rocksdb.manifest.file.sync.micros.p99',
+            'rocksdb.db.get.micros.p50'
+        ]
+        cond1.set_parameter('keys', keys)
+        cond1.set_parameter('aggregation_op', 'latest')
+        # condition evaluates to FALSE
+        cond1.set_parameter('evaluate', 'keys[0]-(keys[1]*100)>200')
+        self.log_stats_parser.check_and_trigger_conditions([cond1])
+        expected_cond_trigger = {NO_ENTITY: [1792.0, 15.9638]}
+        self.assertIsNone(cond1.get_trigger())
+        # condition evaluates to TRUE
+        cond1.set_parameter('evaluate', 'keys[0]-(keys[1]*100)<200')
+        self.log_stats_parser.check_and_trigger_conditions([cond1])
+        expected_cond_trigger = {NO_ENTITY: [1792.0, 15.9638]}
+        self.assertDictEqual(expected_cond_trigger, cond1.get_trigger())
+        # ensure that fetch_timeseries() was called
+        self.log_stats_parser.fetch_timeseries.assert_called()
+
+    def test_check_and_trigger_conditions_eval(self):
+        # mock fetch_timeseries() because 'keys_ts' has been pre-populated
+        self.log_stats_parser.fetch_timeseries = MagicMock()
+        # condition: evaluate_expression
+        cond1 = Condition('cond-1')
+        cond1 = TimeSeriesCondition.create(cond1)
+        cond1.set_parameter('keys', 'rocksdb.db.get.micros.p50')
+        cond1.set_parameter('behavior', 'evaluate_expression')
+        keys = [
+            'rocksdb.manifest.file.sync.micros.p99',
+            'rocksdb.db.get.micros.p50'
+        ]
+        cond1.set_parameter('keys', keys)
+        cond1.set_parameter('evaluate', 'keys[0]-(keys[1]*100)>500')
+        self.log_stats_parser.check_and_trigger_conditions([cond1])
+        expected_trigger = {NO_ENTITY: {
+            1530896414: [9938.0, 16.31508],
+            1530896440: [9938.0, 16.346602],
+            1530896466: [9938.0, 16.284669],
+            1530896492: [9938.0, 16.16005]
+        }}
+        self.assertDictEqual(expected_trigger, cond1.get_trigger())
+        self.log_stats_parser.fetch_timeseries.assert_called_once()
+
+
+class TestDatabasePerfContext(unittest.TestCase):
+    def test_unaccumulate_metrics(self):
+        perf_dict = {
+            "user_key_comparison_count": 675903942,
+            "block_cache_hit_count": 830086,
+        }
+        timestamp = int(time.time())
+        perf_ts = {}
+        for key in perf_dict:
+            perf_ts[key] = {}
+            start_val = perf_dict[key]
+            for ix in range(5):
+                perf_ts[key][timestamp+(ix*10)] = start_val + (2 * ix * ix)
+        db_perf_context = DatabasePerfContext(perf_ts, 10, True)
+        timestamps = [timestamp+(ix*10) for ix in range(1, 5, 1)]
+        values = [val for val in range(2, 15, 4)]
+        inner_dict = {timestamps[ix]: values[ix] for ix in range(4)}
+        expected_keys_ts = {NO_ENTITY: {
+            'user_key_comparison_count': inner_dict,
+            'block_cache_hit_count': inner_dict
+        }}
+        self.assertDictEqual(expected_keys_ts, db_perf_context.keys_ts)
diff --git a/src/rocksdb/tools/advisor/test/test_rule_parser.py b/src/rocksdb/tools/advisor/test/test_rule_parser.py
new file mode 100644
index 00000000..9f1d0bf5
--- /dev/null
+++ b/src/rocksdb/tools/advisor/test/test_rule_parser.py
@@ -0,0 +1,234 @@
+# Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+#  This source code is licensed under both the GPLv2 (found in the
+#  COPYING file in the root directory) and Apache 2.0 License
+#  (found in the LICENSE.Apache file in the root directory).
+
+import os
+import unittest
+from advisor.rule_parser import RulesSpec
+from advisor.db_log_parser import DatabaseLogs, DataSource
+from advisor.db_options_parser import DatabaseOptions
+
+RuleToSuggestions = {
+    "stall-too-many-memtables": [
+        'inc-bg-flush',
+        'inc-write-buffer'
+    ],
+    "stall-too-many-L0": [
+        'inc-max-subcompactions',
+        'inc-max-bg-compactions',
+        'inc-write-buffer-size',
+        'dec-max-bytes-for-level-base',
+        'inc-l0-slowdown-writes-trigger'
+    ],
+    "stop-too-many-L0": [
+        'inc-max-bg-compactions',
+        'inc-write-buffer-size',
+        'inc-l0-stop-writes-trigger'
+    ],
+    "stall-too-many-compaction-bytes": [
+        'inc-max-bg-compactions',
+        'inc-write-buffer-size',
+        'inc-hard-pending-compaction-bytes-limit',
+        'inc-soft-pending-compaction-bytes-limit'
+    ],
+    "level0-level1-ratio": [
+        'l0-l1-ratio-health-check'
+    ]
+}
+
+
+class TestAllRulesTriggered(unittest.TestCase):
+    def setUp(self):
+        # load the Rules
+        this_path = os.path.abspath(os.path.dirname(__file__))
+        ini_path = os.path.join(this_path, 'input_files/triggered_rules.ini')
+        self.db_rules = RulesSpec(ini_path)
+        self.db_rules.load_rules_from_spec()
+        self.db_rules.perform_section_checks()
+        # load the data sources: LOG and OPTIONS
+        log_path = os.path.join(this_path, 'input_files/LOG-0')
+        options_path = os.path.join(this_path, 'input_files/OPTIONS-000005')
+        db_options_parser = DatabaseOptions(options_path)
+        self.column_families = db_options_parser.get_column_families()
+        db_logs_parser = DatabaseLogs(log_path, self.column_families)
+        self.data_sources = {
+            DataSource.Type.DB_OPTIONS: [db_options_parser],
+            DataSource.Type.LOG: [db_logs_parser]
+        }
+
+    def test_triggered_conditions(self):
+        conditions_dict = self.db_rules.get_conditions_dict()
+        rules_dict = self.db_rules.get_rules_dict()
+        # Make sure none of the conditions is triggered beforehand
+        for cond in conditions_dict.values():
+            self.assertFalse(cond.is_triggered(), repr(cond))
+        for rule in rules_dict.values():
+            self.assertFalse(
+                rule.is_triggered(conditions_dict, self.column_families),
+                repr(rule)
+            )
+
+        # # Trigger the conditions as per the data sources.
+        # trigger_conditions(, conditions_dict)
+
+        # Get the set of rules that have been triggered
+        triggered_rules = self.db_rules.get_triggered_rules(
+            self.data_sources, self.column_families
+        )
+
+        # Make sure each condition and rule is triggered
+        for cond in conditions_dict.values():
+            if cond.get_data_source() is DataSource.Type.TIME_SERIES:
+                continue
+            self.assertTrue(cond.is_triggered(), repr(cond))
+
+        for rule in rules_dict.values():
+            self.assertIn(rule, triggered_rules)
+            # Check the suggestions made by the triggered rules
+            for sugg in rule.get_suggestions():
+                self.assertIn(sugg, RuleToSuggestions[rule.name])
+
+        for rule in triggered_rules:
+            self.assertIn(rule, rules_dict.values())
+            for sugg in RuleToSuggestions[rule.name]:
+                self.assertIn(sugg, rule.get_suggestions())
+
+
+class TestConditionsConjunctions(unittest.TestCase):
+    def setUp(self):
+        # load the Rules
+        this_path = os.path.abspath(os.path.dirname(__file__))
+        ini_path = os.path.join(this_path, 'input_files/test_rules.ini')
+        self.db_rules = RulesSpec(ini_path)
+        self.db_rules.load_rules_from_spec()
+        self.db_rules.perform_section_checks()
+        # load the data sources: LOG and OPTIONS
+        log_path = os.path.join(this_path, 'input_files/LOG-1')
+        options_path = os.path.join(this_path, 'input_files/OPTIONS-000005')
+        db_options_parser = DatabaseOptions(options_path)
+        self.column_families = db_options_parser.get_column_families()
+        db_logs_parser = DatabaseLogs(log_path, self.column_families)
+        self.data_sources = {
+            DataSource.Type.DB_OPTIONS: [db_options_parser],
+            DataSource.Type.LOG: [db_logs_parser]
+        }
+
+    def test_condition_conjunctions(self):
+        conditions_dict = self.db_rules.get_conditions_dict()
+        rules_dict = self.db_rules.get_rules_dict()
+        # Make sure none of the conditions is triggered beforehand
+        for cond in conditions_dict.values():
+            self.assertFalse(cond.is_triggered(), repr(cond))
+        for rule in rules_dict.values():
+            self.assertFalse(
+                rule.is_triggered(conditions_dict, self.column_families),
+                repr(rule)
+            )
+
+        # Trigger the conditions as per the data sources.
+        self.db_rules.trigger_conditions(self.data_sources)
+
+        # Check for the conditions
+        conds_triggered = ['log-1-true', 'log-2-true', 'log-3-true']
+        conds_not_triggered = ['log-4-false', 'options-1-false']
+        for cond in conds_triggered:
+            self.assertTrue(conditions_dict[cond].is_triggered(), repr(cond))
+        for cond in conds_not_triggered:
+            self.assertFalse(conditions_dict[cond].is_triggered(), repr(cond))
+
+        # Check for the rules
+        rules_triggered = ['multiple-conds-true']
+        rules_not_triggered = [
+            'single-condition-false',
+            'multiple-conds-one-false',
+            'multiple-conds-all-false'
+        ]
+        for rule_name in rules_triggered:
+            rule = rules_dict[rule_name]
+            self.assertTrue(
+                rule.is_triggered(conditions_dict, self.column_families),
+                repr(rule)
+            )
+        for rule_name in rules_not_triggered:
+            rule = rules_dict[rule_name]
+            self.assertFalse(
+                rule.is_triggered(conditions_dict, self.column_families),
+                repr(rule)
+            )
+
+
+class TestSanityChecker(unittest.TestCase):
+    def setUp(self):
+        this_path = os.path.abspath(os.path.dirname(__file__))
+        ini_path = os.path.join(this_path, 'input_files/rules_err1.ini')
+        db_rules = RulesSpec(ini_path)
+        db_rules.load_rules_from_spec()
+        self.rules_dict = db_rules.get_rules_dict()
+        self.conditions_dict = db_rules.get_conditions_dict()
+        self.suggestions_dict = db_rules.get_suggestions_dict()
+
+    def test_rule_missing_suggestions(self):
+        regex = '.*rule must have at least one suggestion.*'
+        with self.assertRaisesRegex(ValueError, regex):
+            self.rules_dict['missing-suggestions'].perform_checks()
+
+    def test_rule_missing_conditions(self):
+        regex = '.*rule must have at least one condition.*'
+        with self.assertRaisesRegex(ValueError, regex):
+            self.rules_dict['missing-conditions'].perform_checks()
+
+    def test_condition_missing_regex(self):
+        regex = '.*provide regex for log condition.*'
+        with self.assertRaisesRegex(ValueError, regex):
+            self.conditions_dict['missing-regex'].perform_checks()
+
+    def test_condition_missing_options(self):
+        regex = '.*options missing in condition.*'
+        with self.assertRaisesRegex(ValueError, regex):
+            self.conditions_dict['missing-options'].perform_checks()
+
+    def test_condition_missing_expression(self):
+        regex = '.*expression missing in condition.*'
+        with self.assertRaisesRegex(ValueError, regex):
+            self.conditions_dict['missing-expression'].perform_checks()
+
+    def test_suggestion_missing_option(self):
+        regex = '.*provide option or description.*'
+        with self.assertRaisesRegex(ValueError, regex):
+            self.suggestions_dict['missing-option'].perform_checks()
+
+    def test_suggestion_missing_description(self):
+        regex = '.*provide option or description.*'
+        with self.assertRaisesRegex(ValueError, regex):
+            self.suggestions_dict['missing-description'].perform_checks()
+
+
+class TestParsingErrors(unittest.TestCase):
+    def setUp(self):
+        self.this_path = os.path.abspath(os.path.dirname(__file__))
+
+    def test_condition_missing_source(self):
+        ini_path = os.path.join(self.this_path, 'input_files/rules_err2.ini')
+        db_rules = RulesSpec(ini_path)
+        regex = '.*provide source for condition.*'
+        with self.assertRaisesRegex(NotImplementedError, regex):
+            db_rules.load_rules_from_spec()
+
+    def test_suggestion_missing_action(self):
+        ini_path = os.path.join(self.this_path, 'input_files/rules_err3.ini')
+        db_rules = RulesSpec(ini_path)
+        regex = '.*provide action for option.*'
+        with self.assertRaisesRegex(ValueError, regex):
+            db_rules.load_rules_from_spec()
+
+    def test_section_no_name(self):
+        ini_path = os.path.join(self.this_path, 'input_files/rules_err4.ini')
+        db_rules = RulesSpec(ini_path)
+        regex = 'Parsing error: needed section header:.*'
+        with self.assertRaisesRegex(ValueError, regex):
+            db_rules.load_rules_from_spec()
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/src/rocksdb/tools/analyze_txn_stress_test.sh b/src/rocksdb/tools/analyze_txn_stress_test.sh
new file mode 100755
index 00000000..80826060
--- /dev/null
+++ b/src/rocksdb/tools/analyze_txn_stress_test.sh
@@ -0,0 +1,76 @@
+#!/bin/bash
+# Usage:
+# 1. Enable ROCKS_LOG_DETAILS in util/logging.h
+# 2. Run ./transaction_test --gtest_filter="MySQLStyleTransactionTest/MySQLStyleTransactionTest.TransactionStressTest/*" --gtest_break_on_failure
+# 3. SET=1 # 2 or 3
+# 4. LOG=/dev/shm/transaction_testdb_8600601584148590297/LOG
+# 5. grep RandomTransactionVerify $LOG | cut -d' ' -f 12 | sort -n # to find verify snapshots
+# 5. vn=1345
+# 6. vn_1=1340
+# 4. . tools/tools/analyze_txn_stress_test.sh
+echo Input params:
+# The rocksdb LOG path
+echo $LOG
+# Snapshot at which we got RandomTransactionVerify failure
+echo $vn
+# The snapshot before that where RandomTransactionVerify passed
+echo $vn_1
+# The stress tests use 3 sets, one or more might have shown inconsistent results.
+SET=${SET-1} # 1 or 2 or 3
+echo Checking set number $SET
+
+# Find the txns that committed between the two snapshots, and gather their changes made by them in /tmp/changes.txt
+# 2019/02/28-15:25:51.655477 7fffec9ff700 [DEBUG] [ilities/transactions/write_prepared_txn_db.cc:416] Txn 68497 Committing with 68498
+grep Committing $LOG | awk '{if ($9 <= vn && $9 > vn_1) print $0}' vn=$vn vn_1=${vn_1} > /tmp/txn.txt
+# 2019/02/28-15:25:49.046464 7fffe81f5700 [DEBUG] [il/transaction_test_util.cc:216] Commit of 65541 OK (txn12936193128775589751-9089)
+for i in `cat /tmp/txn.txt | awk '{print $6}'`; do grep "Commit of $i " $LOG; done > /tmp/names.txt
+for n in `cat /tmp/names.txt | awk '{print $9}'`; do grep $n $LOG; done > /tmp/changes.txt
+echo "Sum of the changes:"
+cat /tmp/changes.txt | grep Insert | awk '{print $12}' | cut -d= -f1 | cut -d+ -f2 | awk '{sum+=$1} END{print sum}'
+
+# Gather read values at each snapshot
+# 2019/02/28-15:25:51.655926 7fffebbff700 [DEBUG] [il/transaction_test_util.cc:347] VerifyRead at 67972 (67693): 000230 value: 15983
+grep "VerifyRead at ${vn_1} (.*): 000${SET}" $LOG | cut -d' ' -f 9- > /tmp/va.txt
+grep "VerifyRead at ${vn} (.*): 000${SET}" $LOG | cut -d' ' -f 9- > /tmp/vb.txt
+
+# For each key in the 2nd snapshot, find the value read by 1st, do the adds, and see if the results match.
+IFS=$'\n'
+for l in `cat /tmp/vb.txt`; 
+do
+  grep $l /tmp/va.txt > /dev/null ; 
+  if [[ $? -ne 0 ]]; then 
+    #echo $l
+    k=`echo $l | awk '{print $1}'`;
+    v=`echo $l | awk '{print $3}'`;
+    # 2019/02/28-15:25:19.350111 7fffe81f5700 [DEBUG] [il/transaction_test_util.cc:194] Insert (txn12936193128775589751-2298) OK snap: 16289 key:000219 value: 3772+95=3867
+    exp=`grep "\<$k\>" /tmp/changes.txt | tail -1 | cut -d= -f2`;
+    if [[ $v -ne $exp ]]; then echo $l; fi
+  else
+    k=`echo $l | awk '{print $1}'`;
+    grep "\<$k\>" /tmp/changes.txt
+  fi;
+done
+
+# Check that all the keys read in the 1st snapshot are still visible in the 2nd
+for l in `cat /tmp/va.txt`; 
+do
+  k=`echo $l | awk '{print $1}'`;
+  grep "\<$k\>" /tmp/vb.txt > /dev/null
+  if [[ $? -ne 0 ]]; then
+    echo missing key $k
+  fi
+done
+
+# The following found a bug in ValidateSnapshot. It checks if the adds on each key match up.
+grep Insert /tmp/changes.txt | cut -d' ' -f 10 | sort | uniq > /tmp/keys.txt
+for k in `cat /tmp/keys.txt`;
+do
+  grep "\<$k\>" /tmp/changes.txt > /tmp/adds.txt;
+  # 2019/02/28-15:25:19.350111 7fffe81f5700 [DEBUG] [il/transaction_test_util.cc:194] Insert (txn12936193128775589751-2298) OK snap: 16289 key:000219 value: 3772+95=3867
+  START=`head -1 /tmp/adds.txt | cut -d' ' -f 12 | cut -d+ -f1`
+  END=`tail -1 /tmp/adds.txt | cut -d' ' -f 12 | cut -d= -f2`
+  ADDS=`cat /tmp/adds.txt | grep Insert | awk '{print $12}' | cut -d= -f1 | cut -d+ -f2 | awk '{sum+=$1} END{print sum}'`
+  EXP=$((START+ADDS))
+  # If first + all the adds != last then there was an issue with ValidateSnapshot.
+  if [[ $END -ne $EXP ]]; then echo inconsistent txn: $k $START+$ADDS=$END; cat /tmp/adds.txt; return 1; fi
+done
diff --git a/src/rocksdb/tools/auto_sanity_test.sh b/src/rocksdb/tools/auto_sanity_test.sh
new file mode 100755
index 00000000..c98bd661
--- /dev/null
+++ b/src/rocksdb/tools/auto_sanity_test.sh
@@ -0,0 +1,92 @@
+# shellcheck disable=SC2148
+TMP_DIR="${TMPDIR:-/tmp}/rocksdb-sanity-test"
+
+if [ "$#" -lt 2 ]; then
+  echo "usage: ./auto_sanity_test.sh [new_commit] [old_commit]"
+  echo "Missing either [new_commit] or [old_commit], perform sanity check with the latest and 10th latest commits."
+  recent_commits=`git log | grep -e "^commit [a-z0-9]\+$"| head -n10 | sed -e 's/commit //g'`
+  commit_new=`echo "$recent_commits" | head -n1`
+  commit_old=`echo "$recent_commits" | tail -n1`
+  echo "the most recent commits are:"
+  echo "$recent_commits"
+else
+  commit_new=$1
+  commit_old=$2
+fi
+
+if [ ! -d $TMP_DIR ]; then
+  mkdir $TMP_DIR
+fi
+dir_new="${TMP_DIR}/${commit_new}"
+dir_old="${TMP_DIR}/${commit_old}"
+
+function makestuff() {
+  echo "make clean"
+  make clean > /dev/null
+  echo "make db_sanity_test -j32"
+  make db_sanity_test -j32 > /dev/null
+  if [ $? -ne 0 ]; then
+    echo "[ERROR] Failed to perform 'make db_sanity_test'"
+    exit 1
+  fi
+}
+
+rm -r -f $dir_new
+rm -r -f $dir_old
+
+echo "Running db sanity check with commits $commit_new and $commit_old."
+
+echo "============================================================="
+echo "Making build $commit_new"
+git checkout $commit_new
+if [ $? -ne 0 ]; then
+  echo "[ERROR] Can't checkout $commit_new"
+  exit 1
+fi
+makestuff
+mv db_sanity_test new_db_sanity_test
+echo "Creating db based on the new commit --- $commit_new"
+./new_db_sanity_test $dir_new create
+cp ./tools/db_sanity_test.cc $dir_new
+cp ./tools/auto_sanity_test.sh $dir_new
+
+echo "============================================================="
+echo "Making build $commit_old"
+git checkout $commit_old
+if [ $? -ne 0 ]; then
+  echo "[ERROR] Can't checkout $commit_old"
+  exit 1
+fi
+cp -f $dir_new/db_sanity_test.cc ./tools/.
+cp -f $dir_new/auto_sanity_test.sh ./tools/.
+makestuff
+mv db_sanity_test old_db_sanity_test
+echo "Creating db based on the old commit --- $commit_old"
+./old_db_sanity_test $dir_old create
+
+echo "============================================================="
+echo "[Backward Compatibility Check]"
+echo "Verifying old db $dir_old using the new commit --- $commit_new"
+./new_db_sanity_test $dir_old verify
+if [ $? -ne 0 ]; then
+  echo "[ERROR] Backward Compatibility Check fails:"
+  echo "    Verification of $dir_old using commit $commit_new failed."
+  exit 2
+fi
+
+echo "============================================================="
+echo "[Forward Compatibility Check]"
+echo "Verifying new db $dir_new using the old commit --- $commit_old"
+./old_db_sanity_test $dir_new verify
+if [ $? -ne 0 ]; then
+  echo "[ERROR] Forward Compatibility Check fails:"
+  echo "    $dir_new using commit $commit_old failed."
+  exit 2
+fi
+
+rm old_db_sanity_test
+rm new_db_sanity_test
+rm -rf $dir_new
+rm -rf $dir_old
+
+echo "Auto sanity test passed!"
diff --git a/src/rocksdb/tools/benchmark.sh b/src/rocksdb/tools/benchmark.sh
new file mode 100755
index 00000000..31df59cd
--- /dev/null
+++ b/src/rocksdb/tools/benchmark.sh
@@ -0,0 +1,524 @@
+#!/usr/bin/env bash
+# REQUIRE: db_bench binary exists in the current directory
+
+if [ $# -ne 1 ]; then
+  echo -n "./benchmark.sh [bulkload/fillseq/overwrite/filluniquerandom/"
+  echo    "readrandom/readwhilewriting/readwhilemerging/updaterandom/"
+  echo    "mergerandom/randomtransaction/compact]"
+  exit 0
+fi
+
+# Make it easier to run only the compaction test. Getting valid data requires
+# a number of iterations and having an ability to run the test separately from
+# rest of the benchmarks helps.
+if [ "$COMPACTION_TEST" == "1" -a "$1" != "universal_compaction" ]; then
+  echo "Skipping $1 because it's not a compaction test."
+  exit 0
+fi
+
+# size constants
+K=1024
+M=$((1024 * K))
+G=$((1024 * M))
+T=$((1024 * T))
+
+if [ -z $DB_DIR ]; then
+  echo "DB_DIR is not defined"
+  exit 0
+fi
+
+if [ -z $WAL_DIR ]; then
+  echo "WAL_DIR is not defined"
+  exit 0
+fi
+
+output_dir=${OUTPUT_DIR:-/tmp/}
+if [ ! -d $output_dir ]; then
+  mkdir -p $output_dir
+fi
+
+# all multithreaded tests run with sync=1 unless
+# $DB_BENCH_NO_SYNC is defined
+syncval="1"
+if [ ! -z $DB_BENCH_NO_SYNC ]; then
+  echo "Turning sync off for all multithreaded tests"
+  syncval="0";
+fi
+
+num_threads=${NUM_THREADS:-64}
+mb_written_per_sec=${MB_WRITE_PER_SEC:-0}
+# Only for tests that do range scans
+num_nexts_per_seek=${NUM_NEXTS_PER_SEEK:-10}
+cache_size=${CACHE_SIZE:-$((17179869184))}
+compression_max_dict_bytes=${COMPRESSION_MAX_DICT_BYTES:-0}
+compression_type=${COMPRESSION_TYPE:-zstd}
+duration=${DURATION:-0}
+
+num_keys=${NUM_KEYS:-8000000000}
+key_size=${KEY_SIZE:-20}
+value_size=${VALUE_SIZE:-400}
+block_size=${BLOCK_SIZE:-8192}
+
+const_params="
+  --db=$DB_DIR \
+  --wal_dir=$WAL_DIR \
+  \
+  --num=$num_keys \
+  --num_levels=6 \
+  --key_size=$key_size \
+  --value_size=$value_size \
+  --block_size=$block_size \
+  --cache_size=$cache_size \
+  --cache_numshardbits=6 \
+  --compression_max_dict_bytes=$compression_max_dict_bytes \
+  --compression_ratio=0.5 \
+  --compression_type=$compression_type \
+  --level_compaction_dynamic_level_bytes=true \
+  --bytes_per_sync=$((8 * M)) \
+  --cache_index_and_filter_blocks=0 \
+  --pin_l0_filter_and_index_blocks_in_cache=1 \
+  --benchmark_write_rate_limit=$(( 1024 * 1024 * $mb_written_per_sec )) \
+  \
+  --hard_rate_limit=3 \
+  --rate_limit_delay_max_milliseconds=1000000 \
+  --write_buffer_size=$((128 * M)) \
+  --target_file_size_base=$((128 * M)) \
+  --max_bytes_for_level_base=$((1 * G)) \
+  \
+  --verify_checksum=1 \
+  --delete_obsolete_files_period_micros=$((60 * M)) \
+  --max_bytes_for_level_multiplier=8 \
+  \
+  --statistics=0 \
+  --stats_per_interval=1 \
+  --stats_interval_seconds=60 \
+  --histogram=1 \
+  \
+  --memtablerep=skip_list \
+  --bloom_bits=10 \
+  --open_files=-1"
+
+l0_config="
+  --level0_file_num_compaction_trigger=4 \
+  --level0_stop_writes_trigger=20"
+
+if [ $duration -gt 0 ]; then
+  const_params="$const_params --duration=$duration"
+fi
+
+params_w="$const_params \
+          $l0_config \
+          --max_background_compactions=16 \
+          --max_write_buffer_number=8 \
+          --max_background_flushes=7"
+
+params_bulkload="$const_params \
+                 --max_background_compactions=16 \
+                 --max_write_buffer_number=8 \
+                 --allow_concurrent_memtable_write=false \
+                 --max_background_flushes=7 \
+                 --level0_file_num_compaction_trigger=$((10 * M)) \
+                 --level0_slowdown_writes_trigger=$((10 * M)) \
+                 --level0_stop_writes_trigger=$((10 * M))"
+
+params_fillseq="$params_w \
+		--allow_concurrent_memtable_write=false"
+#
+# Tune values for level and universal compaction.
+# For universal compaction, these level0_* options mean total sorted of runs in
+# LSM. In level-based compaction, it means number of L0 files.
+#
+params_level_compact="$const_params \
+                --max_background_flushes=4 \
+                --max_write_buffer_number=4 \
+                --level0_file_num_compaction_trigger=4 \
+                --level0_slowdown_writes_trigger=16 \
+                --level0_stop_writes_trigger=20"
+
+params_univ_compact="$const_params \
+                --max_background_flushes=4 \
+                --max_write_buffer_number=4 \
+                --level0_file_num_compaction_trigger=8 \
+                --level0_slowdown_writes_trigger=16 \
+                --level0_stop_writes_trigger=20"
+
+function summarize_result {
+  test_out=$1
+  test_name=$2
+  bench_name=$3
+
+  # Note that this function assumes that the benchmark executes long enough so
+  # that "Compaction Stats" is written to stdout at least once. If it won't
+  # happen then empty output from grep when searching for "Sum" will cause
+  # syntax errors.
+  uptime=$( grep ^Uptime\(secs $test_out | tail -1 | awk '{ printf "%.0f", $2 }' )
+  stall_time=$( grep "^Cumulative stall" $test_out | tail -1  | awk '{  print $3 }' )
+  stall_pct=$( grep "^Cumulative stall" $test_out| tail -1  | awk '{  print $5 }' )
+  ops_sec=$( grep ^${bench_name} $test_out | awk '{ print $5 }' )
+  mb_sec=$( grep ^${bench_name} $test_out | awk '{ print $7 }' )
+  lo_wgb=$( grep "^  L0" $test_out | tail -1 | awk '{ print $9 }' )
+  sum_wgb=$( grep "^ Sum" $test_out | tail -1 | awk '{ print $9 }' )
+  sum_size=$( grep "^ Sum" $test_out | tail -1 | awk '{ printf "%.1f", $3 / 1024.0 }' )
+  wamp=$( echo "scale=1; $sum_wgb / $lo_wgb" | bc )
+  wmb_ps=$( echo "scale=1; ( $sum_wgb * 1024.0 ) / $uptime" | bc )
+  usecs_op=$( grep ^${bench_name} $test_out | awk '{ printf "%.1f", $3 }' )
+  p50=$( grep "^Percentiles:" $test_out | tail -1 | awk '{ printf "%.1f", $3 }' )
+  p75=$( grep "^Percentiles:" $test_out | tail -1 | awk '{ printf "%.1f", $5 }' )
+  p99=$( grep "^Percentiles:" $test_out | tail -1 | awk '{ printf "%.0f", $7 }' )
+  p999=$( grep "^Percentiles:" $test_out | tail -1 | awk '{ printf "%.0f", $9 }' )
+  p9999=$( grep "^Percentiles:" $test_out | tail -1 | awk '{ printf "%.0f", $11 }' )
+  echo -e "$ops_sec\t$mb_sec\t$sum_size\t$lo_wgb\t$sum_wgb\t$wamp\t$wmb_ps\t$usecs_op\t$p50\t$p75\t$p99\t$p999\t$p9999\t$uptime\t$stall_time\t$stall_pct\t$test_name" \
+    >> $output_dir/report.txt
+}
+
+function run_bulkload {
+  # This runs with a vector memtable and the WAL disabled to load faster. It is still crash safe and the
+  # client can discover where to restart a load after a crash. I think this is a good way to load.
+  echo "Bulk loading $num_keys random keys"
+  cmd="./db_bench --benchmarks=fillrandom \
+       --use_existing_db=0 \
+       --disable_auto_compactions=1 \
+       --sync=0 \
+       $params_bulkload \
+       --threads=1 \
+       --memtablerep=vector \
+       --allow_concurrent_memtable_write=false \
+       --disable_wal=1 \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $output_dir/benchmark_bulkload_fillrandom.log"
+  echo $cmd | tee $output_dir/benchmark_bulkload_fillrandom.log
+  eval $cmd
+  summarize_result $output_dir/benchmark_bulkload_fillrandom.log bulkload fillrandom
+  echo "Compacting..."
+  cmd="./db_bench --benchmarks=compact \
+       --use_existing_db=1 \
+       --disable_auto_compactions=1 \
+       --sync=0 \
+       $params_w \
+       --threads=1 \
+       2>&1 | tee -a $output_dir/benchmark_bulkload_compact.log"
+  echo $cmd | tee $output_dir/benchmark_bulkload_compact.log
+  eval $cmd
+}
+
+#
+# Parameter description:
+#
+# $1 - 1 if I/O statistics should be collected.
+# $2 - compaction type to use (level=0, universal=1).
+# $3 - number of subcompactions.
+# $4 - number of maximum background compactions.
+#
+function run_manual_compaction_worker {
+  # This runs with a vector memtable and the WAL disabled to load faster.
+  # It is still crash safe and the client can discover where to restart a
+  # load after a crash. I think this is a good way to load.
+  echo "Bulk loading $num_keys random keys for manual compaction."
+
+  fillrandom_output_file=$output_dir/benchmark_man_compact_fillrandom_$3.log
+  man_compact_output_log=$output_dir/benchmark_man_compact_$3.log
+
+  if [ "$2" == "1" ]; then
+    extra_params=$params_univ_compact
+  else
+    extra_params=$params_level_compact
+  fi
+
+  # Make sure that fillrandom uses the same compaction options as compact.
+  cmd="./db_bench --benchmarks=fillrandom \
+       --use_existing_db=0 \
+       --disable_auto_compactions=0 \
+       --sync=0 \
+       $extra_params \
+       --threads=$num_threads \
+       --compaction_measure_io_stats=$1 \
+       --compaction_style=$2 \
+       --subcompactions=$3 \
+       --memtablerep=vector \
+       --allow_concurrent_memtable_write=false \
+       --disable_wal=1 \
+       --max_background_compactions=$4 \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $fillrandom_output_file"
+
+  echo $cmd | tee $fillrandom_output_file
+  eval $cmd
+
+  summarize_result $fillrandom_output_file man_compact_fillrandom_$3 fillrandom
+
+  echo "Compacting with $3 subcompactions specified ..."
+
+  # This is the part we're really interested in. Given that compact benchmark
+  # doesn't output regular statistics then we'll just use the time command to
+  # measure how long this step takes.
+  cmd="{ \
+       time ./db_bench --benchmarks=compact \
+       --use_existing_db=1 \
+       --disable_auto_compactions=0 \
+       --sync=0 \
+       $extra_params \
+       --threads=$num_threads \
+       --compaction_measure_io_stats=$1 \
+       --compaction_style=$2 \
+       --subcompactions=$3 \
+       --max_background_compactions=$4 \
+       ;}
+       2>&1 | tee -a $man_compact_output_log"
+
+  echo $cmd | tee $man_compact_output_log
+  eval $cmd
+
+  # Can't use summarize_result here. One way to analyze the results is to run
+  # "grep real" on the resulting log files.
+}
+
+function run_univ_compaction {
+  # Always ask for I/O statistics to be measured.
+  io_stats=1
+
+  # Values: kCompactionStyleLevel = 0x0, kCompactionStyleUniversal = 0x1.
+  compaction_style=1
+
+  # Define a set of benchmarks.
+  subcompactions=(1 2 4 8 16)
+  max_background_compactions=(16 16 8 4 2)
+
+  i=0
+  total=${#subcompactions[@]}
+
+  # Execute a set of benchmarks to cover variety of scenarios.
+  while [ "$i" -lt "$total" ]
+  do
+    run_manual_compaction_worker $io_stats $compaction_style ${subcompactions[$i]} \
+      ${max_background_compactions[$i]}
+    ((i++))
+  done
+}
+
+function run_fillseq {
+  # This runs with a vector memtable. WAL can be either disabled or enabled
+  # depending on the input parameter (1 for disabled, 0 for enabled). The main
+  # benefit behind disabling WAL is to make loading faster. It is still crash
+  # safe and the client can discover where to restart a load after a crash. I
+  # think this is a good way to load.
+
+  # Make sure that we'll have unique names for all the files so that data won't
+  # be overwritten.
+  if [ $1 == 1 ]; then
+    log_file_name=$output_dir/benchmark_fillseq.wal_disabled.v${value_size}.log
+    test_name=fillseq.wal_disabled.v${value_size}
+  else
+    log_file_name=$output_dir/benchmark_fillseq.wal_enabled.v${value_size}.log
+    test_name=fillseq.wal_enabled.v${value_size}
+  fi
+
+  echo "Loading $num_keys keys sequentially"
+  cmd="./db_bench --benchmarks=fillseq \
+       --use_existing_db=0 \
+       --sync=0 \
+       $params_fillseq \
+       --min_level_to_compress=0 \
+       --threads=1 \
+       --memtablerep=vector \
+       --allow_concurrent_memtable_write=false \
+       --disable_wal=$1 \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $log_file_name"
+  echo $cmd | tee $log_file_name
+  eval $cmd
+
+  # The constant "fillseq" which we pass to db_bench is the benchmark name.
+  summarize_result $log_file_name $test_name fillseq
+}
+
+function run_change {
+  operation=$1
+  echo "Do $num_keys random $operation"
+  out_name="benchmark_${operation}.t${num_threads}.s${syncval}.log"
+  cmd="./db_bench --benchmarks=$operation \
+       --use_existing_db=1 \
+       --sync=$syncval \
+       $params_w \
+       --threads=$num_threads \
+       --merge_operator=\"put\" \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $output_dir/${out_name}"
+  echo $cmd | tee $output_dir/${out_name}
+  eval $cmd
+  summarize_result $output_dir/${out_name} ${operation}.t${num_threads}.s${syncval} $operation
+}
+
+function run_filluniquerandom {
+  echo "Loading $num_keys unique keys randomly"
+  cmd="./db_bench --benchmarks=filluniquerandom \
+       --use_existing_db=0 \
+       --sync=0 \
+       $params_w \
+       --threads=1 \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $output_dir/benchmark_filluniquerandom.log"
+  echo $cmd | tee $output_dir/benchmark_filluniquerandom.log
+  eval $cmd
+  summarize_result $output_dir/benchmark_filluniquerandom.log filluniquerandom filluniquerandom
+}
+
+function run_readrandom {
+  echo "Reading $num_keys random keys"
+  out_name="benchmark_readrandom.t${num_threads}.log"
+  cmd="./db_bench --benchmarks=readrandom \
+       --use_existing_db=1 \
+       $params_w \
+       --threads=$num_threads \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $output_dir/${out_name}"
+  echo $cmd | tee $output_dir/${out_name}
+  eval $cmd
+  summarize_result $output_dir/${out_name} readrandom.t${num_threads} readrandom
+}
+
+function run_readwhile {
+  operation=$1
+  echo "Reading $num_keys random keys while $operation"
+  out_name="benchmark_readwhile${operation}.t${num_threads}.log"
+  cmd="./db_bench --benchmarks=readwhile${operation} \
+       --use_existing_db=1 \
+       --sync=$syncval \
+       $params_w \
+       --threads=$num_threads \
+       --merge_operator=\"put\" \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $output_dir/${out_name}"
+  echo $cmd | tee $output_dir/${out_name}
+  eval $cmd
+  summarize_result $output_dir/${out_name} readwhile${operation}.t${num_threads} readwhile${operation}
+}
+
+function run_rangewhile {
+  operation=$1
+  full_name=$2
+  reverse_arg=$3
+  out_name="benchmark_${full_name}.t${num_threads}.log"
+  echo "Range scan $num_keys random keys while ${operation} for reverse_iter=${reverse_arg}"
+  cmd="./db_bench --benchmarks=seekrandomwhile${operation} \
+       --use_existing_db=1 \
+       --sync=$syncval \
+       $params_w \
+       --threads=$num_threads \
+       --merge_operator=\"put\" \
+       --seek_nexts=$num_nexts_per_seek \
+       --reverse_iterator=$reverse_arg \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $output_dir/${out_name}"
+  echo $cmd | tee $output_dir/${out_name}
+  eval $cmd
+  summarize_result $output_dir/${out_name} ${full_name}.t${num_threads} seekrandomwhile${operation}
+}
+
+function run_range {
+  full_name=$1
+  reverse_arg=$2
+  out_name="benchmark_${full_name}.t${num_threads}.log"
+  echo "Range scan $num_keys random keys for reverse_iter=${reverse_arg}"
+  cmd="./db_bench --benchmarks=seekrandom \
+       --use_existing_db=1 \
+       $params_w \
+       --threads=$num_threads \
+       --seek_nexts=$num_nexts_per_seek \
+       --reverse_iterator=$reverse_arg \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $output_dir/${out_name}"
+  echo $cmd | tee $output_dir/${out_name}
+  eval $cmd
+  summarize_result $output_dir/${out_name} ${full_name}.t${num_threads} seekrandom
+}
+
+function run_randomtransaction {
+  echo "..."
+  cmd="./db_bench $params_r --benchmarks=randomtransaction \
+       --num=$num_keys \
+       --transaction_db \
+       --threads=5 \
+       --transaction_sets=5 \
+       2>&1 | tee $output_dir/benchmark_randomtransaction.log"
+  echo $cmd | tee $output_dir/benchmark_rangescanwhilewriting.log
+  eval $cmd
+}
+
+function now() {
+  echo `date +"%s"`
+}
+
+report="$output_dir/report.txt"
+schedule="$output_dir/schedule.txt"
+
+echo "===== Benchmark ====="
+
+# Run!!!
+IFS=',' read -a jobs <<< $1
+# shellcheck disable=SC2068
+for job in ${jobs[@]}; do
+
+  if [ $job != debug ]; then
+    echo "Start $job at `date`" | tee -a $schedule
+  fi
+
+  start=$(now)
+  if [ $job = bulkload ]; then
+    run_bulkload
+  elif [ $job = fillseq_disable_wal ]; then
+    run_fillseq 1
+  elif [ $job = fillseq_enable_wal ]; then
+    run_fillseq 0
+  elif [ $job = overwrite ]; then
+    syncval="0"
+    params_w="$params_w \
+	--writes=125000000 \
+	--subcompactions=4 \
+	--soft_pending_compaction_bytes_limit=$((1 * T)) \
+	--hard_pending_compaction_bytes_limit=$((4 * T)) "
+    run_change overwrite
+  elif [ $job = updaterandom ]; then
+    run_change updaterandom
+  elif [ $job = mergerandom ]; then
+    run_change mergerandom
+  elif [ $job = filluniquerandom ]; then
+    run_filluniquerandom
+  elif [ $job = readrandom ]; then
+    run_readrandom
+  elif [ $job = fwdrange ]; then
+    run_range $job false
+  elif [ $job = revrange ]; then
+    run_range $job true
+  elif [ $job = readwhilewriting ]; then
+    run_readwhile writing
+  elif [ $job = readwhilemerging ]; then
+    run_readwhile merging
+  elif [ $job = fwdrangewhilewriting ]; then
+    run_rangewhile writing $job false
+  elif [ $job = revrangewhilewriting ]; then
+    run_rangewhile writing $job true
+  elif [ $job = fwdrangewhilemerging ]; then
+    run_rangewhile merging $job false
+  elif [ $job = revrangewhilemerging ]; then
+    run_rangewhile merging $job true
+  elif [ $job = randomtransaction ]; then
+    run_randomtransaction
+  elif [ $job = universal_compaction ]; then
+    run_univ_compaction
+  elif [ $job = debug ]; then
+    num_keys=1000; # debug
+    echo "Setting num_keys to $num_keys"
+  else
+    echo "unknown job $job"
+    exit
+  fi
+  end=$(now)
+
+  if [ $job != debug ]; then
+    echo "Complete $job in $((end-start)) seconds" | tee -a $schedule
+  fi
+
+  echo -e "ops/sec\tmb/sec\tSize-GB\tL0_GB\tSum_GB\tW-Amp\tW-MB/s\tusec/op\tp50\tp75\tp99\tp99.9\tp99.99\tUptime\tStall-time\tStall%\tTest"
+  tail -1 $output_dir/report.txt
+
+done
diff --git a/src/rocksdb/tools/benchmark_leveldb.sh b/src/rocksdb/tools/benchmark_leveldb.sh
new file mode 100755
index 00000000..40c7733c
--- /dev/null
+++ b/src/rocksdb/tools/benchmark_leveldb.sh
@@ -0,0 +1,186 @@
+#!/usr/bin/env bash
+# REQUIRE: db_bench binary exists in the current directory
+#
+# This should be used with the LevelDB fork listed here to use additional test options.
+# For more details on the changes see the blog post listed below.
+#   https://github.com/mdcallag/leveldb-1
+#   http://smalldatum.blogspot.com/2015/04/comparing-leveldb-and-rocksdb-take-2.html
+
+if [ $# -ne 1 ]; then
+  echo -n "./benchmark.sh [fillseq/overwrite/readrandom/readwhilewriting]"
+  exit 0
+fi
+
+# size constants
+K=1024
+M=$((1024 * K))
+G=$((1024 * M))
+
+if [ -z $DB_DIR ]; then
+  echo "DB_DIR is not defined"
+  exit 0
+fi
+
+output_dir=${OUTPUT_DIR:-/tmp/}
+if [ ! -d $output_dir ]; then
+  mkdir -p $output_dir
+fi
+
+# all multithreaded tests run with sync=1 unless
+# $DB_BENCH_NO_SYNC is defined
+syncval="1"
+if [ ! -z $DB_BENCH_NO_SYNC ]; then
+  echo "Turning sync off for all multithreaded tests"
+  syncval="0";
+fi
+
+num_threads=${NUM_THREADS:-16}
+# Only for *whilewriting, *whilemerging
+writes_per_second=${WRITES_PER_SECOND:-$((10 * K))}
+cache_size=${CACHE_SIZE:-$((1 * G))}
+
+num_keys=${NUM_KEYS:-$((1 * G))}
+key_size=20
+value_size=${VALUE_SIZE:-400}
+block_size=${BLOCK_SIZE:-4096}
+
+const_params="
+  --db=$DB_DIR \
+  \
+  --num=$num_keys \
+  --value_size=$value_size \
+  --cache_size=$cache_size \
+  --compression_ratio=0.5 \
+  \
+  --write_buffer_size=$((2 * M)) \
+  \
+  --histogram=1 \
+  \
+  --bloom_bits=10 \
+  --open_files=$((20 * K))"
+
+params_w="$const_params "
+
+function summarize_result {
+  test_out=$1
+  test_name=$2
+  bench_name=$3
+  nthr=$4
+
+  usecs_op=$( grep ^${bench_name} $test_out | awk '{ printf "%.1f", $3 }' )
+  mb_sec=$( grep ^${bench_name} $test_out | awk '{ printf "%.1f", $5 }' )
+  ops=$( grep "^Count:" $test_out | awk '{ print $2 }' )
+  ops_sec=$( echo "scale=0; (1000000.0 * $nthr) / $usecs_op" | bc )
+  avg=$( grep "^Count:" $test_out | awk '{ printf "%.1f", $4 }' )
+  p50=$( grep "^Min:" $test_out | awk '{ printf "%.1f", $4 }' )
+  echo -e "$ops_sec\t$mb_sec\t$usecs_op\t$avg\t$p50\t$test_name" \
+    >> $output_dir/report.txt
+}
+
+function run_fillseq {
+  # This runs with a vector memtable and the WAL disabled to load faster. It is still crash safe and the
+  # client can discover where to restart a load after a crash. I think this is a good way to load.
+  echo "Loading $num_keys keys sequentially"
+  cmd="./db_bench --benchmarks=fillseq \
+       --use_existing_db=0 \
+       --sync=0 \
+       $params_w \
+       --threads=1 \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $output_dir/benchmark_fillseq.v${value_size}.log"
+  echo $cmd | tee $output_dir/benchmark_fillseq.v${value_size}.log
+  eval $cmd
+  summarize_result $output_dir/benchmark_fillseq.v${value_size}.log fillseq.v${value_size} fillseq 1
+}
+
+function run_change {
+  operation=$1
+  echo "Do $num_keys random $operation"
+  out_name="benchmark_${operation}.t${num_threads}.s${syncval}.log"
+  cmd="./db_bench --benchmarks=$operation \
+       --use_existing_db=1 \
+       --sync=$syncval \
+       $params_w \
+       --threads=$num_threads \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $output_dir/${out_name}"
+  echo $cmd | tee $output_dir/${out_name}
+  eval $cmd
+  summarize_result $output_dir/${out_name} ${operation}.t${num_threads}.s${syncval} $operation $num_threads
+}
+
+function run_readrandom {
+  echo "Reading $num_keys random keys"
+  out_name="benchmark_readrandom.t${num_threads}.log"
+  cmd="./db_bench --benchmarks=readrandom \
+       --use_existing_db=1 \
+       $params_w \
+       --threads=$num_threads \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $output_dir/${out_name}"
+  echo $cmd | tee $output_dir/${out_name}
+  eval $cmd
+  summarize_result $output_dir/${out_name} readrandom.t${num_threads} readrandom $num_threads
+}
+
+function run_readwhile {
+  operation=$1
+  echo "Reading $num_keys random keys while $operation"
+  out_name="benchmark_readwhile${operation}.t${num_threads}.log"
+  cmd="./db_bench --benchmarks=readwhile${operation} \
+       --use_existing_db=1 \
+       --sync=$syncval \
+       $params_w \
+       --threads=$num_threads \
+       --writes_per_second=$writes_per_second \
+       --seed=$( date +%s ) \
+       2>&1 | tee -a $output_dir/${out_name}"
+  echo $cmd | tee $output_dir/${out_name}
+  eval $cmd
+  summarize_result $output_dir/${out_name} readwhile${operation}.t${num_threads} readwhile${operation} $num_threads
+}
+
+function now() {
+  echo `date +"%s"`
+}
+
+report="$output_dir/report.txt"
+schedule="$output_dir/schedule.txt"
+
+echo "===== Benchmark ====="
+
+# Run!!!
+IFS=',' read -a jobs <<< $1
+# shellcheck disable=SC2068
+for job in ${jobs[@]}; do
+
+  if [ $job != debug ]; then
+    echo "Start $job at `date`" | tee -a $schedule
+  fi
+
+  start=$(now)
+  if [ $job = fillseq ]; then
+    run_fillseq
+  elif [ $job = overwrite ]; then
+    run_change overwrite
+  elif [ $job = readrandom ]; then
+    run_readrandom
+  elif [ $job = readwhilewriting ]; then
+    run_readwhile writing
+  elif [ $job = debug ]; then
+    num_keys=1000; # debug
+    echo "Setting num_keys to $num_keys"
+  else
+    echo "unknown job $job"
+    exit
+  fi
+  end=$(now)
+
+  if [ $job != debug ]; then
+    echo "Complete $job in $((end-start)) seconds" | tee -a $schedule
+  fi
+
+  echo -e "ops/sec\tmb/sec\tusec/op\tavg\tp50\tTest"
+  tail -1 $output_dir/report.txt
+
+done
diff --git a/src/rocksdb/tools/blob_dump.cc b/src/rocksdb/tools/blob_dump.cc
new file mode 100644
index 00000000..7da61085
--- /dev/null
+++ b/src/rocksdb/tools/blob_dump.cc
@@ -0,0 +1,110 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#ifndef ROCKSDB_LITE
+#include <getopt.h>
+#include <cstdio>
+#include <string>
+#include <unordered_map>
+
+#include "utilities/blob_db/blob_dump_tool.h"
+
+using namespace rocksdb;
+using namespace rocksdb::blob_db;
+
+int main(int argc, char** argv) {
+  using DisplayType = BlobDumpTool::DisplayType;
+  const std::unordered_map<std::string, DisplayType> display_types = {
+      {"none", DisplayType::kNone},
+      {"raw", DisplayType::kRaw},
+      {"hex", DisplayType::kHex},
+      {"detail", DisplayType::kDetail},
+  };
+  const struct option options[] = {
+      {"help", no_argument, nullptr, 'h'},
+      {"file", required_argument, nullptr, 'f'},
+      {"show_key", optional_argument, nullptr, 'k'},
+      {"show_blob", optional_argument, nullptr, 'b'},
+      {"show_uncompressed_blob", optional_argument, nullptr, 'r'},
+      {"show_summary", optional_argument, nullptr, 's'},
+  };
+  DisplayType show_key = DisplayType::kRaw;
+  DisplayType show_blob = DisplayType::kNone;
+  DisplayType show_uncompressed_blob = DisplayType::kNone;
+  bool show_summary = false;
+  std::string file;
+  while (true) {
+    int c = getopt_long(argc, argv, "hk::b::f:", options, nullptr);
+    if (c < 0) {
+      break;
+    }
+    std::string arg_str(optarg ? optarg : "");
+    switch (c) {
+      case 'h':
+        fprintf(stdout,
+                "Usage: blob_dump --file=filename "
+                "[--show_key[=none|raw|hex|detail]] "
+                "[--show_blob[=none|raw|hex|detail]] "
+                "[--show_uncompressed_blob[=none|raw|hex|detail]] "
+                "[--show_summary]\n");
+        return 0;
+      case 'f':
+        file = optarg;
+        break;
+      case 'k':
+        if (optarg) {
+          if (display_types.count(arg_str) == 0) {
+            fprintf(stderr, "Unrecognized key display type.\n");
+            return -1;
+          }
+          show_key = display_types.at(arg_str);
+        }
+        break;
+      case 'b':
+        if (optarg) {
+          if (display_types.count(arg_str) == 0) {
+            fprintf(stderr, "Unrecognized blob display type.\n");
+            return -1;
+          }
+          show_blob = display_types.at(arg_str);
+        } else {
+          show_blob = DisplayType::kHex;
+        }
+        break;
+      case 'r':
+        if (optarg) {
+          if (display_types.count(arg_str) == 0) {
+            fprintf(stderr, "Unrecognized blob display type.\n");
+            return -1;
+          }
+          show_uncompressed_blob = display_types.at(arg_str);
+        } else {
+          show_uncompressed_blob = DisplayType::kHex;
+        }
+        break;
+      case 's':
+        show_summary = true;
+        break;
+      default:
+        fprintf(stderr, "Unrecognized option.\n");
+        return -1;
+    }
+  }
+  BlobDumpTool tool;
+  Status s =
+      tool.Run(file, show_key, show_blob, show_uncompressed_blob, show_summary);
+  if (!s.ok()) {
+    fprintf(stderr, "Failed: %s\n", s.ToString().c_str());
+    return -1;
+  }
+  return 0;
+}
+#else
+#include <stdio.h>
+int main(int /*argc*/, char** /*argv*/) {
+  fprintf(stderr, "Not supported in lite mode.\n");
+  return -1;
+}
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/check_format_compatible.sh b/src/rocksdb/tools/check_format_compatible.sh
new file mode 100755
index 00000000..a849b9e7
--- /dev/null
+++ b/src/rocksdb/tools/check_format_compatible.sh
@@ -0,0 +1,190 @@
+#!/usr/bin/env bash
+#
+# A shell script to load some pre generated data file to a DB using ldb tool
+# ./ldb needs to be avaible to be executed.
+#
+# Usage: <SCRIPT> [checkout]
+# `checkout` can be a tag, commit or branch name. Will build using it and check DBs generated by all previous branches (or tags for very old versions without branch) can be opened by it.
+# Return value 0 means all regression tests pass. 1 if not pass.
+
+scriptpath=`dirname $BASH_SOURCE`
+test_dir=${TEST_TMPDIR:-"/tmp"}"/format_compatible_check"
+script_copy_dir=$test_dir"/script_copy"
+input_data_path=$test_dir"/test_data_input/"
+
+mkdir $test_dir || true
+mkdir $input_data_path || true
+rm -rf $script_copy_dir
+cp $scriptpath $script_copy_dir -rf
+
+# Generate random files.
+for i in {1..6}
+do
+  input_data[$i]=$input_data_path/data$i
+  echo == Generating random input file ${input_data[$i]}
+  python - <<EOF
+import random
+random.seed($i)
+symbols=['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
+with open('${input_data[$i]}', 'w') as f:
+  for i in range(1,1024):
+    k = ""
+    for j in range(1, random.randint(1,32)):
+      k=k + symbols[random.randint(0, len(symbols) - 1)]
+    vb = ""
+    for j in range(1, random.randint(0,128)):
+      vb = vb + symbols[random.randint(0, len(symbols) - 1)]
+    v = ""
+    for j in range(1, random.randint(1, 5)):
+      v = v + vb
+    print >> f, k + " ==> " + v
+EOF
+done
+
+# Generate file(s) with sorted keys.
+sorted_input_data=$input_data_path/sorted_data
+echo == Generating file with sorted keys ${sorted_input_data}
+python - <<EOF
+with open('${sorted_input_data}', 'w') as f:
+  for i in range(0,10):
+    k = str(i)
+    v = "value" + k
+    print >> f, k + " ==> " + v
+EOF
+
+declare -a backward_compatible_checkout_objs=("2.2.fb.branch" "2.3.fb.branch" "2.4.fb.branch" "2.5.fb.branch" "2.6.fb.branch" "2.7.fb.branch" "2.8.1.fb" "3.0.fb.branch" "3.1.fb" "3.2.fb" "3.3.fb" "3.4.fb" "3.5.fb" "3.6.fb" "3.7.fb" "3.8.fb" "3.9.fb")
+declare -a forward_compatible_checkout_objs=("3.10.fb" "3.11.fb" "3.12.fb" "3.13.fb" "4.0.fb" "4.1.fb" "4.2.fb" "4.3.fb" "4.4.fb" "4.5.fb" "4.6.fb" "4.7.fb" "4.8.fb" "4.9.fb" "4.10.fb" "4.11.fb" "4.12.fb" "4.13.fb" "5.0.fb" "5.1.fb" "5.2.fb" "5.3.fb" "5.4.fb" "5.5.fb" "5.6.fb" "5.7.fb" "5.8.fb" "5.9.fb" "5.10.fb")
+declare -a forward_compatible_with_options_checkout_objs=("5.11.fb" "5.12.fb" "5.13.fb" "5.14.fb")
+declare -a checkout_objs=(${backward_compatible_checkout_objs[@]} ${forward_compatible_checkout_objs[@]} ${forward_compatible_with_options_checkout_objs[@]})
+declare -a extern_sst_ingestion_compatible_checkout_objs=("5.14.fb" "5.15.fb" "5.16.fb" "5.17.fb" "5.18.fb")
+
+generate_db()
+{
+    set +e
+    $script_copy_dir/generate_random_db.sh $1 $2
+    if [ $? -ne 0 ]; then
+        echo ==== Error loading data from $2 to $1 ====
+        exit 1
+    fi
+    set -e
+}
+
+compare_db()
+{
+    set +e
+    $script_copy_dir/verify_random_db.sh $1 $2 $3 $4 $5
+    if [ $? -ne 0 ]; then
+        echo ==== Read different content from $1 and $2 or error happened. ====
+        exit 1
+    fi
+    set -e
+}
+
+write_external_sst()
+{
+    set +e
+    $script_copy_dir/write_external_sst.sh $1 $2 $3
+    if [ $? -ne 0 ]; then
+        echo ==== Error writing external SST file using data from $1 to $3 ====
+        exit 1
+    fi
+    set -e
+}
+
+ingest_external_sst()
+{
+    set +e
+    $script_copy_dir/ingest_external_sst.sh $1 $2
+    if [ $? -ne 0 ]; then
+        echo ==== Error ingesting external SST in $2 to DB at $1 ====
+        exit 1
+    fi
+    set -e
+}
+
+# Sandcastle sets us up with a remote that is just another directory on the same
+# machine and doesn't have our branches. Need to fetch them so checkout works.
+# Remote add may fail if added previously (we don't cleanup).
+git remote add github_origin "https://github.com/facebook/rocksdb.git"
+set -e
+https_proxy="fwdproxy:8080" git fetch github_origin
+
+# Compatibility test for external SST file ingestion
+for checkout_obj in "${extern_sst_ingestion_compatible_checkout_objs[@]}"
+do
+  echo == Generating DB with extern SST file in "$checkout_obj" ...
+  https_proxy="fwdproxy:8080" git checkout github_origin/$checkout_obj -b $checkout_obj
+  make clean
+  make ldb -j32
+  write_external_sst $input_data_path $test_dir/$checkout_obj $test_dir/$checkout_obj
+  ingest_external_sst $test_dir/$checkout_obj $test_dir/$checkout_obj
+done
+
+checkout_flag=${1:-"master"}
+
+echo == Building $checkout_flag debug
+https_proxy="fwdproxy:8080" git checkout github_origin/$checkout_flag -b tmp-$checkout_flag
+make clean
+make ldb -j32
+compare_base_db_dir=$test_dir"/base_db_dir"
+write_external_sst $input_data_path $compare_base_db_dir $compare_base_db_dir
+ingest_external_sst $compare_base_db_dir $compare_base_db_dir
+
+for checkout_obj in "${extern_sst_ingestion_compatible_checkout_objs[@]}"
+do
+  echo == Build "$checkout_obj" and try to open DB generated using $checkout_flag
+  git checkout $checkout_obj
+  make clean
+  make ldb -j32
+  compare_db $test_dir/$checkout_obj $compare_base_db_dir db_dump.txt 1 1
+  git checkout tmp-$checkout_flag
+  # Clean up
+  git branch -D $checkout_obj
+done
+
+echo == Finish compatibility test for SST ingestion.
+
+for checkout_obj in "${checkout_objs[@]}"
+do
+   echo == Generating DB from "$checkout_obj" ...
+   https_proxy="fwdproxy:8080" git checkout github_origin/$checkout_obj -b $checkout_obj
+   make clean
+   make ldb -j32
+   generate_db $input_data_path $test_dir/$checkout_obj
+done
+
+checkout_flag=${1:-"master"}
+
+echo == Building $checkout_flag debug
+git checkout tmp-$checkout_flag
+make clean
+make ldb -j32
+compare_base_db_dir=$test_dir"/base_db_dir"
+echo == Generate compare base DB to $compare_base_db_dir
+generate_db $input_data_path $compare_base_db_dir
+
+for checkout_obj in "${checkout_objs[@]}"
+do
+   echo == Opening DB from "$checkout_obj" using debug build of $checkout_flag ...
+   compare_db $test_dir/$checkout_obj $compare_base_db_dir db_dump.txt 1 0
+done
+
+for checkout_obj in "${forward_compatible_checkout_objs[@]}"
+do
+   echo == Build "$checkout_obj" and try to open DB generated using $checkout_flag...
+   git checkout $checkout_obj
+   make clean
+   make ldb -j32
+   compare_db $test_dir/$checkout_obj $compare_base_db_dir forward_${checkout_obj}_dump.txt 0
+done
+
+for checkout_obj in "${forward_compatible_with_options_checkout_objs[@]}"
+do
+   echo == Build "$checkout_obj" and try to open DB generated using $checkout_flag with its options...
+   git checkout $checkout_obj
+   make clean
+   make ldb -j32
+   compare_db $test_dir/$checkout_obj $compare_base_db_dir forward_${checkout_obj}_dump.txt 1 1
+done
+
+echo ==== Compatibility Test PASSED ====
diff --git a/src/rocksdb/tools/db_bench.cc b/src/rocksdb/tools/db_bench.cc
new file mode 100644
index 00000000..634bbba3
--- /dev/null
+++ b/src/rocksdb/tools/db_bench.cc
@@ -0,0 +1,23 @@
+//  Copyright (c) 2013-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#ifndef __STDC_FORMAT_MACROS
+#define __STDC_FORMAT_MACROS
+#endif
+
+#ifndef GFLAGS
+#include <cstdio>
+int main() {
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+  return 1;
+}
+#else
+#include <rocksdb/db_bench_tool.h>
+int main(int argc, char** argv) { return rocksdb::db_bench_tool(argc, argv); }
+#endif  // GFLAGS
diff --git a/src/rocksdb/tools/db_bench_tool.cc b/src/rocksdb/tools/db_bench_tool.cc
new file mode 100644
index 00000000..0cb4e0eb
--- /dev/null
+++ b/src/rocksdb/tools/db_bench_tool.cc
@@ -0,0 +1,6217 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#ifndef __STDC_FORMAT_MACROS
+#define __STDC_FORMAT_MACROS
+#endif
+
+#ifdef GFLAGS
+#ifdef NUMA
+#include <numa.h>
+#include <numaif.h>
+#endif
+#ifndef OS_WIN
+#include <unistd.h>
+#endif
+#include <fcntl.h>
+#include <inttypes.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <atomic>
+#include <condition_variable>
+#include <cstddef>
+#include <memory>
+#include <mutex>
+#include <thread>
+#include <unordered_map>
+
+#include "db/db_impl.h"
+#include "db/malloc_stats.h"
+#include "db/version_set.h"
+#include "hdfs/env_hdfs.h"
+#include "monitoring/histogram.h"
+#include "monitoring/statistics.h"
+#include "options/cf_options.h"
+#include "port/port.h"
+#include "port/stack_trace.h"
+#include "rocksdb/cache.h"
+#include "rocksdb/db.h"
+#include "rocksdb/env.h"
+#include "rocksdb/filter_policy.h"
+#include "rocksdb/memtablerep.h"
+#include "rocksdb/options.h"
+#include "rocksdb/perf_context.h"
+#include "rocksdb/persistent_cache.h"
+#include "rocksdb/rate_limiter.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/slice_transform.h"
+#include "rocksdb/utilities/object_registry.h"
+#include "rocksdb/utilities/optimistic_transaction_db.h"
+#include "rocksdb/utilities/options_util.h"
+#include "rocksdb/utilities/sim_cache.h"
+#include "rocksdb/utilities/transaction.h"
+#include "rocksdb/utilities/transaction_db.h"
+#include "rocksdb/write_batch.h"
+#include "util/cast_util.h"
+#include "util/compression.h"
+#include "util/crc32c.h"
+#include "util/gflags_compat.h"
+#include "util/mutexlock.h"
+#include "util/random.h"
+#include "util/stderr_logger.h"
+#include "util/string_util.h"
+#include "util/testutil.h"
+#include "util/transaction_test_util.h"
+#include "util/xxhash.h"
+#include "utilities/blob_db/blob_db.h"
+#include "utilities/merge_operators.h"
+#include "utilities/merge_operators/bytesxor.h"
+#include "utilities/persistent_cache/block_cache_tier.h"
+
+#ifdef OS_WIN
+#include <io.h>  // open/close
+#endif
+
+using GFLAGS_NAMESPACE::ParseCommandLineFlags;
+using GFLAGS_NAMESPACE::RegisterFlagValidator;
+using GFLAGS_NAMESPACE::SetUsageMessage;
+
+DEFINE_string(
+    benchmarks,
+    "fillseq,"
+    "fillseqdeterministic,"
+    "fillsync,"
+    "fillrandom,"
+    "filluniquerandomdeterministic,"
+    "overwrite,"
+    "readrandom,"
+    "newiterator,"
+    "newiteratorwhilewriting,"
+    "seekrandom,"
+    "seekrandomwhilewriting,"
+    "seekrandomwhilemerging,"
+    "readseq,"
+    "readreverse,"
+    "compact,"
+    "compactall,"
+    "multireadrandom,"
+    "mixgraph,"
+    "readseq,"
+    "readtocache,"
+    "readreverse,"
+    "readwhilewriting,"
+    "readwhilemerging,"
+    "readwhilescanning,"
+    "readrandomwriterandom,"
+    "updaterandom,"
+    "xorupdaterandom,"
+    "randomwithverify,"
+    "fill100K,"
+    "crc32c,"
+    "xxhash,"
+    "compress,"
+    "uncompress,"
+    "acquireload,"
+    "fillseekseq,"
+    "randomtransaction,"
+    "randomreplacekeys,"
+    "timeseries",
+
+    "Comma-separated list of operations to run in the specified"
+    " order. Available benchmarks:\n"
+    "\tfillseq       -- write N values in sequential key"
+    " order in async mode\n"
+    "\tfillseqdeterministic       -- write N values in the specified"
+    " key order and keep the shape of the LSM tree\n"
+    "\tfillrandom    -- write N values in random key order in async"
+    " mode\n"
+    "\tfilluniquerandomdeterministic       -- write N values in a random"
+    " key order and keep the shape of the LSM tree\n"
+    "\toverwrite     -- overwrite N values in random key order in"
+    " async mode\n"
+    "\tfillsync      -- write N/100 values in random key order in "
+    "sync mode\n"
+    "\tfill100K      -- write N/1000 100K values in random order in"
+    " async mode\n"
+    "\tdeleteseq     -- delete N keys in sequential order\n"
+    "\tdeleterandom  -- delete N keys in random order\n"
+    "\treadseq       -- read N times sequentially\n"
+    "\treadtocache   -- 1 thread reading database sequentially\n"
+    "\treadreverse   -- read N times in reverse order\n"
+    "\treadrandom    -- read N times in random order\n"
+    "\treadmissing   -- read N missing keys in random order\n"
+    "\treadwhilewriting      -- 1 writer, N threads doing random "
+    "reads\n"
+    "\treadwhilemerging      -- 1 merger, N threads doing random "
+    "reads\n"
+    "\treadwhilescanning     -- 1 thread doing full table scan, "
+    "N threads doing random reads\n"
+    "\treadrandomwriterandom -- N threads doing random-read, "
+    "random-write\n"
+    "\tupdaterandom  -- N threads doing read-modify-write for random "
+    "keys\n"
+    "\txorupdaterandom  -- N threads doing read-XOR-write for "
+    "random keys\n"
+    "\tappendrandom  -- N threads doing read-modify-write with "
+    "growing values\n"
+    "\tmergerandom   -- same as updaterandom/appendrandom using merge"
+    " operator. "
+    "Must be used with merge_operator\n"
+    "\treadrandommergerandom -- perform N random read-or-merge "
+    "operations. Must be used with merge_operator\n"
+    "\tnewiterator   -- repeated iterator creation\n"
+    "\tseekrandom    -- N random seeks, call Next seek_nexts times "
+    "per seek\n"
+    "\tseekrandomwhilewriting -- seekrandom and 1 thread doing "
+    "overwrite\n"
+    "\tseekrandomwhilemerging -- seekrandom and 1 thread doing "
+    "merge\n"
+    "\tcrc32c        -- repeated crc32c of 4K of data\n"
+    "\txxhash        -- repeated xxHash of 4K of data\n"
+    "\tacquireload   -- load N*1000 times\n"
+    "\tfillseekseq   -- write N values in sequential key, then read "
+    "them by seeking to each key\n"
+    "\trandomtransaction     -- execute N random transactions and "
+    "verify correctness\n"
+    "\trandomreplacekeys     -- randomly replaces N keys by deleting "
+    "the old version and putting the new version\n\n"
+    "\ttimeseries            -- 1 writer generates time series data "
+    "and multiple readers doing random reads on id\n\n"
+    "Meta operations:\n"
+    "\tcompact     -- Compact the entire DB; If multiple, randomly choose one\n"
+    "\tcompactall  -- Compact the entire DB\n"
+    "\tstats       -- Print DB stats\n"
+    "\tresetstats  -- Reset DB stats\n"
+    "\tlevelstats  -- Print the number of files and bytes per level\n"
+    "\tsstables    -- Print sstable info\n"
+    "\theapprofile -- Dump a heap profile (if supported by this port)\n"
+    "\treplay      -- replay the trace file specified with trace_file\n");
+
+DEFINE_int64(num, 1000000, "Number of key/values to place in database");
+
+DEFINE_int64(numdistinct, 1000,
+             "Number of distinct keys to use. Used in RandomWithVerify to "
+             "read/write on fewer keys so that gets are more likely to find the"
+             " key and puts are more likely to update the same key");
+
+DEFINE_int64(merge_keys, -1,
+             "Number of distinct keys to use for MergeRandom and "
+             "ReadRandomMergeRandom. "
+             "If negative, there will be FLAGS_num keys.");
+DEFINE_int32(num_column_families, 1, "Number of Column Families to use.");
+
+DEFINE_int32(
+    num_hot_column_families, 0,
+    "Number of Hot Column Families. If more than 0, only write to this "
+    "number of column families. After finishing all the writes to them, "
+    "create new set of column families and insert to them. Only used "
+    "when num_column_families > 1.");
+
+DEFINE_string(column_family_distribution, "",
+              "Comma-separated list of percentages, where the ith element "
+              "indicates the probability of an op using the ith column family. "
+              "The number of elements must be `num_hot_column_families` if "
+              "specified; otherwise, it must be `num_column_families`. The "
+              "sum of elements must be 100. E.g., if `num_column_families=4`, "
+              "and `num_hot_column_families=0`, a valid list could be "
+              "\"10,20,30,40\".");
+
+DEFINE_int64(reads, -1, "Number of read operations to do.  "
+             "If negative, do FLAGS_num reads.");
+
+DEFINE_int64(deletes, -1, "Number of delete operations to do.  "
+             "If negative, do FLAGS_num deletions.");
+
+DEFINE_int32(bloom_locality, 0, "Control bloom filter probes locality");
+
+DEFINE_int64(seed, 0, "Seed base for random number generators. "
+             "When 0 it is deterministic.");
+
+DEFINE_int32(threads, 1, "Number of concurrent threads to run.");
+
+DEFINE_int32(duration, 0, "Time in seconds for the random-ops tests to run."
+             " When 0 then num & reads determine the test duration");
+
+DEFINE_int32(value_size, 100, "Size of each value");
+
+DEFINE_int32(seek_nexts, 0,
+             "How many times to call Next() after Seek() in "
+             "fillseekseq, seekrandom, seekrandomwhilewriting and "
+             "seekrandomwhilemerging");
+
+DEFINE_bool(reverse_iterator, false,
+            "When true use Prev rather than Next for iterators that do "
+            "Seek and then Next");
+
+DEFINE_int64(max_scan_distance, 0,
+             "Used to define iterate_upper_bound (or iterate_lower_bound "
+             "if FLAGS_reverse_iterator is set to true) when value is nonzero");
+
+DEFINE_bool(use_uint64_comparator, false, "use Uint64 user comparator");
+
+DEFINE_int64(batch_size, 1, "Batch size");
+
+static bool ValidateKeySize(const char* /*flagname*/, int32_t /*value*/) {
+  return true;
+}
+
+static bool ValidateUint32Range(const char* flagname, uint64_t value) {
+  if (value > std::numeric_limits<uint32_t>::max()) {
+    fprintf(stderr, "Invalid value for --%s: %lu, overflow\n", flagname,
+            (unsigned long)value);
+    return false;
+  }
+  return true;
+}
+
+DEFINE_int32(key_size, 16, "size of each key");
+
+DEFINE_int32(num_multi_db, 0,
+             "Number of DBs used in the benchmark. 0 means single DB.");
+
+DEFINE_double(compression_ratio, 0.5, "Arrange to generate values that shrink"
+              " to this fraction of their original size after compression");
+
+DEFINE_double(read_random_exp_range, 0.0,
+              "Read random's key will be generated using distribution of "
+              "num * exp(-r) where r is uniform number from 0 to this value. "
+              "The larger the number is, the more skewed the reads are. "
+              "Only used in readrandom and multireadrandom benchmarks.");
+
+DEFINE_bool(histogram, false, "Print histogram of operation timings");
+
+DEFINE_bool(enable_numa, false,
+            "Make operations aware of NUMA architecture and bind memory "
+            "and cpus corresponding to nodes together. In NUMA, memory "
+            "in same node as CPUs are closer when compared to memory in "
+            "other nodes. Reads can be faster when the process is bound to "
+            "CPU and memory of same node. Use \"$numactl --hardware\" command "
+            "to see NUMA memory architecture.");
+
+DEFINE_int64(db_write_buffer_size, rocksdb::Options().db_write_buffer_size,
+             "Number of bytes to buffer in all memtables before compacting");
+
+DEFINE_bool(cost_write_buffer_to_cache, false,
+            "The usage of memtable is costed to the block cache");
+
+DEFINE_int64(write_buffer_size, rocksdb::Options().write_buffer_size,
+             "Number of bytes to buffer in memtable before compacting");
+
+DEFINE_int32(max_write_buffer_number,
+             rocksdb::Options().max_write_buffer_number,
+             "The number of in-memory memtables. Each memtable is of size"
+             " write_buffer_size bytes.");
+
+DEFINE_int32(min_write_buffer_number_to_merge,
+             rocksdb::Options().min_write_buffer_number_to_merge,
+             "The minimum number of write buffers that will be merged together"
+             "before writing to storage. This is cheap because it is an"
+             "in-memory merge. If this feature is not enabled, then all these"
+             "write buffers are flushed to L0 as separate files and this "
+             "increases read amplification because a get request has to check"
+             " in all of these files. Also, an in-memory merge may result in"
+             " writing less data to storage if there are duplicate records "
+             " in each of these individual write buffers.");
+
+DEFINE_int32(max_write_buffer_number_to_maintain,
+             rocksdb::Options().max_write_buffer_number_to_maintain,
+             "The total maximum number of write buffers to maintain in memory "
+             "including copies of buffers that have already been flushed. "
+             "Unlike max_write_buffer_number, this parameter does not affect "
+             "flushing. This controls the minimum amount of write history "
+             "that will be available in memory for conflict checking when "
+             "Transactions are used. If this value is too low, some "
+             "transactions may fail at commit time due to not being able to "
+             "determine whether there were any write conflicts. Setting this "
+             "value to 0 will cause write buffers to be freed immediately "
+             "after they are flushed.  If this value is set to -1, "
+             "'max_write_buffer_number' will be used.");
+
+DEFINE_int32(max_background_jobs,
+             rocksdb::Options().max_background_jobs,
+             "The maximum number of concurrent background jobs that can occur "
+             "in parallel.");
+
+DEFINE_int32(num_bottom_pri_threads, 0,
+             "The number of threads in the bottom-priority thread pool (used "
+             "by universal compaction only).");
+
+DEFINE_int32(num_high_pri_threads, 0,
+             "The maximum number of concurrent background compactions"
+             " that can occur in parallel.");
+
+DEFINE_int32(num_low_pri_threads, 0,
+             "The maximum number of concurrent background compactions"
+             " that can occur in parallel.");
+
+DEFINE_int32(max_background_compactions,
+             rocksdb::Options().max_background_compactions,
+             "The maximum number of concurrent background compactions"
+             " that can occur in parallel.");
+
+DEFINE_int32(base_background_compactions, -1, "DEPRECATED");
+
+DEFINE_uint64(subcompactions, 1,
+              "Maximum number of subcompactions to divide L0-L1 compactions "
+              "into.");
+static const bool FLAGS_subcompactions_dummy
+    __attribute__((__unused__)) = RegisterFlagValidator(&FLAGS_subcompactions,
+                                                    &ValidateUint32Range);
+
+DEFINE_int32(max_background_flushes,
+             rocksdb::Options().max_background_flushes,
+             "The maximum number of concurrent background flushes"
+             " that can occur in parallel.");
+
+static rocksdb::CompactionStyle FLAGS_compaction_style_e;
+DEFINE_int32(compaction_style, (int32_t) rocksdb::Options().compaction_style,
+             "style of compaction: level-based, universal and fifo");
+
+static rocksdb::CompactionPri FLAGS_compaction_pri_e;
+DEFINE_int32(compaction_pri, (int32_t)rocksdb::Options().compaction_pri,
+             "priority of files to compaction: by size or by data age");
+
+DEFINE_int32(universal_size_ratio, 0,
+             "Percentage flexibility while comparing file size"
+             " (for universal compaction only).");
+
+DEFINE_int32(universal_min_merge_width, 0, "The minimum number of files in a"
+             " single compaction run (for universal compaction only).");
+
+DEFINE_int32(universal_max_merge_width, 0, "The max number of files to compact"
+             " in universal style compaction");
+
+DEFINE_int32(universal_max_size_amplification_percent, 0,
+             "The max size amplification for universal style compaction");
+
+DEFINE_int32(universal_compression_size_percent, -1,
+             "The percentage of the database to compress for universal "
+             "compaction. -1 means compress everything.");
+
+DEFINE_bool(universal_allow_trivial_move, false,
+            "Allow trivial move in universal compaction.");
+
+DEFINE_int64(cache_size, 8 << 20,  // 8MB
+             "Number of bytes to use as a cache of uncompressed data");
+
+DEFINE_int32(cache_numshardbits, 6,
+             "Number of shards for the block cache"
+             " is 2 ** cache_numshardbits. Negative means use default settings."
+             " This is applied only if FLAGS_cache_size is non-negative.");
+
+DEFINE_double(cache_high_pri_pool_ratio, 0.0,
+              "Ratio of block cache reserve for high pri blocks. "
+              "If > 0.0, we also enable "
+              "cache_index_and_filter_blocks_with_high_priority.");
+
+DEFINE_bool(use_clock_cache, false,
+            "Replace default LRU block cache with clock cache.");
+
+DEFINE_int64(simcache_size, -1,
+             "Number of bytes to use as a simcache of "
+             "uncompressed data. Nagative value disables simcache.");
+
+DEFINE_bool(cache_index_and_filter_blocks, false,
+            "Cache index/filter blocks in block cache.");
+
+DEFINE_bool(partition_index_and_filters, false,
+            "Partition index and filter blocks.");
+
+DEFINE_bool(partition_index, false, "Partition index blocks");
+
+DEFINE_int64(metadata_block_size,
+             rocksdb::BlockBasedTableOptions().metadata_block_size,
+             "Max partition size when partitioning index/filters");
+
+// The default reduces the overhead of reading time with flash. With HDD, which
+// offers much less throughput, however, this number better to be set to 1.
+DEFINE_int32(ops_between_duration_checks, 1000,
+             "Check duration limit every x ops");
+
+DEFINE_bool(pin_l0_filter_and_index_blocks_in_cache, false,
+            "Pin index/filter blocks of L0 files in block cache.");
+
+DEFINE_bool(
+    pin_top_level_index_and_filter, false,
+    "Pin top-level index of partitioned index/filter blocks in block cache.");
+
+DEFINE_int32(block_size,
+             static_cast<int32_t>(rocksdb::BlockBasedTableOptions().block_size),
+             "Number of bytes in a block.");
+
+DEFINE_int32(
+    format_version,
+    static_cast<int32_t>(rocksdb::BlockBasedTableOptions().format_version),
+    "Format version of SST files.");
+
+DEFINE_int32(block_restart_interval,
+             rocksdb::BlockBasedTableOptions().block_restart_interval,
+             "Number of keys between restart points "
+             "for delta encoding of keys in data block.");
+
+DEFINE_int32(index_block_restart_interval,
+             rocksdb::BlockBasedTableOptions().index_block_restart_interval,
+             "Number of keys between restart points "
+             "for delta encoding of keys in index block.");
+
+DEFINE_int32(read_amp_bytes_per_bit,
+             rocksdb::BlockBasedTableOptions().read_amp_bytes_per_bit,
+             "Number of bytes per bit to be used in block read-amp bitmap");
+
+DEFINE_bool(enable_index_compression,
+            rocksdb::BlockBasedTableOptions().enable_index_compression,
+            "Compress the index block");
+
+DEFINE_bool(block_align, rocksdb::BlockBasedTableOptions().block_align,
+            "Align data blocks on page size");
+
+DEFINE_bool(use_data_block_hash_index, false,
+            "if use kDataBlockBinaryAndHash "
+            "instead of kDataBlockBinarySearch. "
+            "This is valid if only we use BlockTable");
+
+DEFINE_double(data_block_hash_table_util_ratio, 0.75,
+              "util ratio for data block hash index table. "
+              "This is only valid if use_data_block_hash_index is "
+              "set to true");
+
+DEFINE_int64(compressed_cache_size, -1,
+             "Number of bytes to use as a cache of compressed data.");
+
+DEFINE_int64(row_cache_size, 0,
+             "Number of bytes to use as a cache of individual rows"
+             " (0 = disabled).");
+
+DEFINE_int32(open_files, rocksdb::Options().max_open_files,
+             "Maximum number of files to keep open at the same time"
+             " (use default if == 0)");
+
+DEFINE_int32(file_opening_threads, rocksdb::Options().max_file_opening_threads,
+             "If open_files is set to -1, this option set the number of "
+             "threads that will be used to open files during DB::Open()");
+
+DEFINE_bool(new_table_reader_for_compaction_inputs, true,
+             "If true, uses a separate file handle for compaction inputs");
+
+DEFINE_int32(compaction_readahead_size, 0, "Compaction readahead size");
+
+DEFINE_int32(random_access_max_buffer_size, 1024 * 1024,
+             "Maximum windows randomaccess buffer size");
+
+DEFINE_int32(writable_file_max_buffer_size, 1024 * 1024,
+             "Maximum write buffer for Writable File");
+
+DEFINE_int32(bloom_bits, -1, "Bloom filter bits per key. Negative means"
+             " use default settings.");
+DEFINE_double(memtable_bloom_size_ratio, 0,
+              "Ratio of memtable size used for bloom filter. 0 means no bloom "
+              "filter.");
+DEFINE_bool(memtable_whole_key_filtering, false,
+            "Try to use whole key bloom filter in memtables.");
+DEFINE_bool(memtable_use_huge_page, false,
+            "Try to use huge page in memtables.");
+
+DEFINE_bool(use_existing_db, false, "If true, do not destroy the existing"
+            " database.  If you set this flag and also specify a benchmark that"
+            " wants a fresh database, that benchmark will fail.");
+
+DEFINE_bool(use_existing_keys, false,
+            "If true, uses existing keys in the DB, "
+            "rather than generating new ones. This involves some startup "
+            "latency to load all keys into memory. It is supported for the "
+            "same read/overwrite benchmarks as `-use_existing_db=true`, which "
+            "must also be set for this flag to be enabled. When this flag is "
+            "set, the value for `-num` will be ignored.");
+
+DEFINE_bool(show_table_properties, false,
+            "If true, then per-level table"
+            " properties will be printed on every stats-interval when"
+            " stats_interval is set and stats_per_interval is on.");
+
+DEFINE_string(db, "", "Use the db with the following name.");
+
+// Read cache flags
+
+DEFINE_string(read_cache_path, "",
+              "If not empty string, a read cache will be used in this path");
+
+DEFINE_int64(read_cache_size, 4LL * 1024 * 1024 * 1024,
+             "Maximum size of the read cache");
+
+DEFINE_bool(read_cache_direct_write, true,
+            "Whether to use Direct IO for writing to the read cache");
+
+DEFINE_bool(read_cache_direct_read, true,
+            "Whether to use Direct IO for reading from read cache");
+
+DEFINE_bool(use_keep_filter, false, "Whether to use a noop compaction filter");
+
+static bool ValidateCacheNumshardbits(const char* flagname, int32_t value) {
+  if (value >= 20) {
+    fprintf(stderr, "Invalid value for --%s: %d, must be < 20\n",
+            flagname, value);
+    return false;
+  }
+  return true;
+}
+
+DEFINE_bool(verify_checksum, true,
+            "Verify checksum for every block read"
+            " from storage");
+
+DEFINE_bool(statistics, false, "Database statistics");
+DEFINE_int32(stats_level, rocksdb::StatsLevel::kExceptDetailedTimers,
+             "stats level for statistics");
+DEFINE_string(statistics_string, "", "Serialized statistics string");
+static class std::shared_ptr<rocksdb::Statistics> dbstats;
+
+DEFINE_int64(writes, -1, "Number of write operations to do. If negative, do"
+             " --num reads.");
+
+DEFINE_bool(finish_after_writes, false, "Write thread terminates after all writes are finished");
+
+DEFINE_bool(sync, false, "Sync all writes to disk");
+
+DEFINE_bool(use_fsync, false, "If true, issue fsync instead of fdatasync");
+
+DEFINE_bool(disable_wal, false, "If true, do not write WAL for write.");
+
+DEFINE_string(wal_dir, "", "If not empty, use the given dir for WAL");
+
+DEFINE_string(truth_db, "/dev/shm/truth_db/dbbench",
+              "Truth key/values used when using verify");
+
+DEFINE_int32(num_levels, 7, "The total number of levels");
+
+DEFINE_int64(target_file_size_base, rocksdb::Options().target_file_size_base,
+             "Target file size at level-1");
+
+DEFINE_int32(target_file_size_multiplier,
+             rocksdb::Options().target_file_size_multiplier,
+             "A multiplier to compute target level-N file size (N >= 2)");
+
+DEFINE_uint64(max_bytes_for_level_base,
+              rocksdb::Options().max_bytes_for_level_base,
+              "Max bytes for level-1");
+
+DEFINE_bool(level_compaction_dynamic_level_bytes, false,
+            "Whether level size base is dynamic");
+
+DEFINE_double(max_bytes_for_level_multiplier, 10,
+              "A multiplier to compute max bytes for level-N (N >= 2)");
+
+static std::vector<int> FLAGS_max_bytes_for_level_multiplier_additional_v;
+DEFINE_string(max_bytes_for_level_multiplier_additional, "",
+              "A vector that specifies additional fanout per level");
+
+DEFINE_int32(level0_stop_writes_trigger,
+             rocksdb::Options().level0_stop_writes_trigger,
+             "Number of files in level-0"
+             " that will trigger put stop.");
+
+DEFINE_int32(level0_slowdown_writes_trigger,
+             rocksdb::Options().level0_slowdown_writes_trigger,
+             "Number of files in level-0"
+             " that will slow down writes.");
+
+DEFINE_int32(level0_file_num_compaction_trigger,
+             rocksdb::Options().level0_file_num_compaction_trigger,
+             "Number of files in level-0"
+             " when compactions start");
+
+static bool ValidateInt32Percent(const char* flagname, int32_t value) {
+  if (value <= 0 || value>=100) {
+    fprintf(stderr, "Invalid value for --%s: %d, 0< pct <100 \n",
+            flagname, value);
+    return false;
+  }
+  return true;
+}
+DEFINE_int32(readwritepercent, 90, "Ratio of reads to reads/writes (expressed"
+             " as percentage) for the ReadRandomWriteRandom workload. The "
+             "default value 90 means 90% operations out of all reads and writes"
+             " operations are reads. In other words, 9 gets for every 1 put.");
+
+DEFINE_int32(mergereadpercent, 70, "Ratio of merges to merges&reads (expressed"
+             " as percentage) for the ReadRandomMergeRandom workload. The"
+             " default value 70 means 70% out of all read and merge operations"
+             " are merges. In other words, 7 merges for every 3 gets.");
+
+DEFINE_int32(deletepercent, 2, "Percentage of deletes out of reads/writes/"
+             "deletes (used in RandomWithVerify only). RandomWithVerify "
+             "calculates writepercent as (100 - FLAGS_readwritepercent - "
+             "deletepercent), so deletepercent must be smaller than (100 - "
+             "FLAGS_readwritepercent)");
+
+DEFINE_bool(optimize_filters_for_hits, false,
+            "Optimizes bloom filters for workloads for most lookups return "
+            "a value. For now this doesn't create bloom filters for the max "
+            "level of the LSM to reduce metadata that should fit in RAM. ");
+
+DEFINE_uint64(delete_obsolete_files_period_micros, 0,
+              "Ignored. Left here for backward compatibility");
+
+DEFINE_int64(writes_before_delete_range, 0,
+             "Number of writes before DeleteRange is called regularly.");
+
+DEFINE_int64(writes_per_range_tombstone, 0,
+             "Number of writes between range tombstones");
+
+DEFINE_int64(range_tombstone_width, 100, "Number of keys in tombstone's range");
+
+DEFINE_int64(max_num_range_tombstones, 0,
+             "Maximum number of range tombstones "
+             "to insert.");
+
+DEFINE_bool(expand_range_tombstones, false,
+            "Expand range tombstone into sequential regular tombstones.");
+
+#ifndef ROCKSDB_LITE
+// Transactions Options
+DEFINE_bool(optimistic_transaction_db, false,
+            "Open a OptimisticTransactionDB instance. "
+            "Required for randomtransaction benchmark.");
+
+DEFINE_bool(transaction_db, false,
+            "Open a TransactionDB instance. "
+            "Required for randomtransaction benchmark.");
+
+DEFINE_uint64(transaction_sets, 2,
+              "Number of keys each transaction will "
+              "modify (use in RandomTransaction only).  Max: 9999");
+
+DEFINE_bool(transaction_set_snapshot, false,
+            "Setting to true will have each transaction call SetSnapshot()"
+            " upon creation.");
+
+DEFINE_int32(transaction_sleep, 0,
+             "Max microseconds to sleep in between "
+             "reading and writing a value (used in RandomTransaction only). ");
+
+DEFINE_uint64(transaction_lock_timeout, 100,
+              "If using a transaction_db, specifies the lock wait timeout in"
+              " milliseconds before failing a transaction waiting on a lock");
+DEFINE_string(
+    options_file, "",
+    "The path to a RocksDB options file.  If specified, then db_bench will "
+    "run with the RocksDB options in the default column family of the "
+    "specified options file. "
+    "Note that with this setting, db_bench will ONLY accept the following "
+    "RocksDB options related command-line arguments, all other arguments "
+    "that are related to RocksDB options will be ignored:\n"
+    "\t--use_existing_db\n"
+    "\t--use_existing_keys\n"
+    "\t--statistics\n"
+    "\t--row_cache_size\n"
+    "\t--row_cache_numshardbits\n"
+    "\t--enable_io_prio\n"
+    "\t--dump_malloc_stats\n"
+    "\t--num_multi_db\n");
+
+// FIFO Compaction Options
+DEFINE_uint64(fifo_compaction_max_table_files_size_mb, 0,
+              "The limit of total table file sizes to trigger FIFO compaction");
+
+DEFINE_bool(fifo_compaction_allow_compaction, true,
+            "Allow compaction in FIFO compaction.");
+
+DEFINE_uint64(fifo_compaction_ttl, 0, "TTL for the SST Files in seconds.");
+
+// Blob DB Options
+DEFINE_bool(use_blob_db, false,
+            "Open a BlobDB instance. "
+            "Required for large value benchmark.");
+
+DEFINE_bool(blob_db_enable_gc, false, "Enable BlobDB garbage collection.");
+
+DEFINE_bool(blob_db_is_fifo, false, "Enable FIFO eviction strategy in BlobDB.");
+
+DEFINE_uint64(blob_db_max_db_size, 0,
+              "Max size limit of the directory where blob files are stored.");
+
+DEFINE_uint64(blob_db_max_ttl_range, 86400,
+              "TTL range to generate BlobDB data (in seconds).");
+
+DEFINE_uint64(blob_db_ttl_range_secs, 3600,
+              "TTL bucket size to use when creating blob files.");
+
+DEFINE_uint64(blob_db_min_blob_size, 0,
+              "Smallest blob to store in a file. Blobs smaller than this "
+              "will be inlined with the key in the LSM tree.");
+
+DEFINE_uint64(blob_db_bytes_per_sync, 0, "Bytes to sync blob file at.");
+
+DEFINE_uint64(blob_db_file_size, 256 * 1024 * 1024,
+              "Target size of each blob file.");
+
+#endif  // ROCKSDB_LITE
+
+DEFINE_bool(report_bg_io_stats, false,
+            "Measure times spents on I/Os while in compactions. ");
+
+DEFINE_bool(use_stderr_info_logger, false,
+            "Write info logs to stderr instead of to LOG file. ");
+
+DEFINE_string(trace_file, "", "Trace workload to a file. ");
+
+static enum rocksdb::CompressionType StringToCompressionType(const char* ctype) {
+  assert(ctype);
+
+  if (!strcasecmp(ctype, "none"))
+    return rocksdb::kNoCompression;
+  else if (!strcasecmp(ctype, "snappy"))
+    return rocksdb::kSnappyCompression;
+  else if (!strcasecmp(ctype, "zlib"))
+    return rocksdb::kZlibCompression;
+  else if (!strcasecmp(ctype, "bzip2"))
+    return rocksdb::kBZip2Compression;
+  else if (!strcasecmp(ctype, "lz4"))
+    return rocksdb::kLZ4Compression;
+  else if (!strcasecmp(ctype, "lz4hc"))
+    return rocksdb::kLZ4HCCompression;
+  else if (!strcasecmp(ctype, "xpress"))
+    return rocksdb::kXpressCompression;
+  else if (!strcasecmp(ctype, "zstd"))
+    return rocksdb::kZSTD;
+
+  fprintf(stdout, "Cannot parse compression type '%s'\n", ctype);
+  return rocksdb::kSnappyCompression;  // default value
+}
+
+static std::string ColumnFamilyName(size_t i) {
+  if (i == 0) {
+    return rocksdb::kDefaultColumnFamilyName;
+  } else {
+    char name[100];
+    snprintf(name, sizeof(name), "column_family_name_%06zu", i);
+    return std::string(name);
+  }
+}
+
+DEFINE_string(compression_type, "snappy",
+              "Algorithm to use to compress the database");
+static enum rocksdb::CompressionType FLAGS_compression_type_e =
+    rocksdb::kSnappyCompression;
+
+DEFINE_int64(sample_for_compression, 0, "Sample every N block for compression");
+
+DEFINE_int32(compression_level, rocksdb::CompressionOptions().level,
+             "Compression level. The meaning of this value is library-"
+             "dependent. If unset, we try to use the default for the library "
+             "specified in `--compression_type`");
+
+DEFINE_int32(compression_max_dict_bytes,
+             rocksdb::CompressionOptions().max_dict_bytes,
+             "Maximum size of dictionary used to prime the compression "
+             "library.");
+
+DEFINE_int32(compression_zstd_max_train_bytes,
+             rocksdb::CompressionOptions().zstd_max_train_bytes,
+             "Maximum size of training data passed to zstd's dictionary "
+             "trainer.");
+
+DEFINE_int32(min_level_to_compress, -1, "If non-negative, compression starts"
+             " from this level. Levels with number < min_level_to_compress are"
+             " not compressed. Otherwise, apply compression_type to "
+             "all levels.");
+
+static bool ValidateTableCacheNumshardbits(const char* flagname,
+                                           int32_t value) {
+  if (0 >= value || value > 20) {
+    fprintf(stderr, "Invalid value for --%s: %d, must be  0 < val <= 20\n",
+            flagname, value);
+    return false;
+  }
+  return true;
+}
+DEFINE_int32(table_cache_numshardbits, 4, "");
+
+#ifndef ROCKSDB_LITE
+DEFINE_string(env_uri, "", "URI for registry Env lookup. Mutually exclusive"
+              " with --hdfs.");
+#endif  // ROCKSDB_LITE
+DEFINE_string(hdfs, "", "Name of hdfs environment. Mutually exclusive with"
+              " --env_uri.");
+static rocksdb::Env* FLAGS_env = rocksdb::Env::Default();
+
+DEFINE_int64(stats_interval, 0, "Stats are reported every N operations when "
+             "this is greater than zero. When 0 the interval grows over time.");
+
+DEFINE_int64(stats_interval_seconds, 0, "Report stats every N seconds. This "
+             "overrides stats_interval when both are > 0.");
+
+DEFINE_int32(stats_per_interval, 0, "Reports additional stats per interval when"
+             " this is greater than 0.");
+
+DEFINE_int64(report_interval_seconds, 0,
+             "If greater than zero, it will write simple stats in CVS format "
+             "to --report_file every N seconds");
+
+DEFINE_string(report_file, "report.csv",
+              "Filename where some simple stats are reported to (if "
+              "--report_interval_seconds is bigger than 0)");
+
+DEFINE_int32(thread_status_per_interval, 0,
+             "Takes and report a snapshot of the current status of each thread"
+             " when this is greater than 0.");
+
+DEFINE_int32(perf_level, rocksdb::PerfLevel::kDisable, "Level of perf collection");
+
+static bool ValidateRateLimit(const char* flagname, double value) {
+  const double EPSILON = 1e-10;
+  if ( value < -EPSILON ) {
+    fprintf(stderr, "Invalid value for --%s: %12.6f, must be >= 0.0\n",
+            flagname, value);
+    return false;
+  }
+  return true;
+}
+DEFINE_double(soft_rate_limit, 0.0, "DEPRECATED");
+
+DEFINE_double(hard_rate_limit, 0.0, "DEPRECATED");
+
+DEFINE_uint64(soft_pending_compaction_bytes_limit, 64ull * 1024 * 1024 * 1024,
+              "Slowdown writes if pending compaction bytes exceed this number");
+
+DEFINE_uint64(hard_pending_compaction_bytes_limit, 128ull * 1024 * 1024 * 1024,
+              "Stop writes if pending compaction bytes exceed this number");
+
+DEFINE_uint64(delayed_write_rate, 8388608u,
+              "Limited bytes allowed to DB when soft_rate_limit or "
+              "level0_slowdown_writes_trigger triggers");
+
+DEFINE_bool(enable_pipelined_write, true,
+            "Allow WAL and memtable writes to be pipelined");
+
+DEFINE_bool(allow_concurrent_memtable_write, true,
+            "Allow multi-writers to update mem tables in parallel.");
+
+DEFINE_bool(inplace_update_support, rocksdb::Options().inplace_update_support,
+            "Support in-place memtable update for smaller or same-size values");
+
+DEFINE_uint64(inplace_update_num_locks,
+              rocksdb::Options().inplace_update_num_locks,
+              "Number of RW locks to protect in-place memtable updates");
+
+DEFINE_bool(enable_write_thread_adaptive_yield, true,
+            "Use a yielding spin loop for brief writer thread waits.");
+
+DEFINE_uint64(
+    write_thread_max_yield_usec, 100,
+    "Maximum microseconds for enable_write_thread_adaptive_yield operation.");
+
+DEFINE_uint64(write_thread_slow_yield_usec, 3,
+              "The threshold at which a slow yield is considered a signal that "
+              "other processes or threads want the core.");
+
+DEFINE_int32(rate_limit_delay_max_milliseconds, 1000,
+             "When hard_rate_limit is set then this is the max time a put will"
+             " be stalled.");
+
+DEFINE_uint64(rate_limiter_bytes_per_sec, 0, "Set options.rate_limiter value.");
+
+DEFINE_bool(rate_limiter_auto_tuned, false,
+            "Enable dynamic adjustment of rate limit according to demand for "
+            "background I/O");
+
+
+DEFINE_bool(sine_write_rate, false,
+            "Use a sine wave write_rate_limit");
+
+DEFINE_uint64(sine_write_rate_interval_milliseconds, 10000,
+              "Interval of which the sine wave write_rate_limit is recalculated");
+
+DEFINE_double(sine_a, 1,
+             "A in f(x) = A sin(bx + c) + d");
+
+DEFINE_double(sine_b, 1,
+             "B in f(x) = A sin(bx + c) + d");
+
+DEFINE_double(sine_c, 0,
+             "C in f(x) = A sin(bx + c) + d");
+
+DEFINE_double(sine_d, 1,
+             "D in f(x) = A sin(bx + c) + d");
+
+DEFINE_bool(rate_limit_bg_reads, false,
+            "Use options.rate_limiter on compaction reads");
+
+DEFINE_uint64(
+    benchmark_write_rate_limit, 0,
+    "If non-zero, db_bench will rate-limit the writes going into RocksDB. This "
+    "is the global rate in bytes/second.");
+
+// the parameters of mix_graph
+DEFINE_double(key_dist_a, 0.0,
+              "The parameter 'a' of key access distribution model "
+              "f(x)=a*x^b");
+DEFINE_double(key_dist_b, 0.0,
+              "The parameter 'b' of key access distribution model "
+              "f(x)=a*x^b");
+DEFINE_double(value_theta, 0.0,
+              "The parameter 'theta' of Generized Pareto Distribution "
+              "f(x)=(1/sigma)*(1+k*(x-theta)/sigma)^-(1/k+1)");
+DEFINE_double(value_k, 0.0,
+              "The parameter 'k' of Generized Pareto Distribution "
+              "f(x)=(1/sigma)*(1+k*(x-theta)/sigma)^-(1/k+1)");
+DEFINE_double(value_sigma, 0.0,
+              "The parameter 'theta' of Generized Pareto Distribution "
+              "f(x)=(1/sigma)*(1+k*(x-theta)/sigma)^-(1/k+1)");
+DEFINE_double(iter_theta, 0.0,
+              "The parameter 'theta' of Generized Pareto Distribution "
+              "f(x)=(1/sigma)*(1+k*(x-theta)/sigma)^-(1/k+1)");
+DEFINE_double(iter_k, 0.0,
+              "The parameter 'k' of Generized Pareto Distribution "
+              "f(x)=(1/sigma)*(1+k*(x-theta)/sigma)^-(1/k+1)");
+DEFINE_double(iter_sigma, 0.0,
+              "The parameter 'sigma' of Generized Pareto Distribution "
+              "f(x)=(1/sigma)*(1+k*(x-theta)/sigma)^-(1/k+1)");
+DEFINE_double(mix_get_ratio, 1.0,
+              "The ratio of Get queries of mix_graph workload");
+DEFINE_double(mix_put_ratio, 0.0,
+              "The ratio of Put queries of mix_graph workload");
+DEFINE_double(mix_seek_ratio, 0.0,
+              "The ratio of Seek queries of mix_graph workload");
+DEFINE_int64(mix_max_scan_len, 10000, "The max scan length of Iterator");
+DEFINE_int64(mix_ave_kv_size, 512,
+             "The average key-value size of this workload");
+DEFINE_int64(mix_max_value_size, 1024, "The max value size of this workload");
+DEFINE_double(
+    sine_mix_rate_noise, 0.0,
+    "Add the noise ratio to the sine rate, it is between 0.0 and 1.0");
+DEFINE_bool(sine_mix_rate, false,
+            "Enable the sine QPS control on the mix workload");
+DEFINE_uint64(
+    sine_mix_rate_interval_milliseconds, 10000,
+    "Interval of which the sine wave read_rate_limit is recalculated");
+DEFINE_int64(mix_accesses, -1,
+             "The total query accesses of mix_graph workload");
+
+DEFINE_uint64(
+    benchmark_read_rate_limit, 0,
+    "If non-zero, db_bench will rate-limit the reads from RocksDB. This "
+    "is the global rate in ops/second.");
+
+DEFINE_uint64(max_compaction_bytes, rocksdb::Options().max_compaction_bytes,
+              "Max bytes allowed in one compaction");
+
+#ifndef ROCKSDB_LITE
+DEFINE_bool(readonly, false, "Run read only benchmarks.");
+
+DEFINE_bool(print_malloc_stats, false,
+            "Print malloc stats to stdout after benchmarks finish.");
+#endif  // ROCKSDB_LITE
+
+DEFINE_bool(disable_auto_compactions, false, "Do not auto trigger compactions");
+
+DEFINE_uint64(wal_ttl_seconds, 0, "Set the TTL for the WAL Files in seconds.");
+DEFINE_uint64(wal_size_limit_MB, 0, "Set the size limit for the WAL Files"
+              " in MB.");
+DEFINE_uint64(max_total_wal_size, 0, "Set total max WAL size");
+
+DEFINE_bool(mmap_read, rocksdb::Options().allow_mmap_reads,
+            "Allow reads to occur via mmap-ing files");
+
+DEFINE_bool(mmap_write, rocksdb::Options().allow_mmap_writes,
+            "Allow writes to occur via mmap-ing files");
+
+DEFINE_bool(use_direct_reads, rocksdb::Options().use_direct_reads,
+            "Use O_DIRECT for reading data");
+
+DEFINE_bool(use_direct_io_for_flush_and_compaction,
+            rocksdb::Options().use_direct_io_for_flush_and_compaction,
+            "Use O_DIRECT for background flush and compaction writes");
+
+DEFINE_bool(advise_random_on_open, rocksdb::Options().advise_random_on_open,
+            "Advise random access on table file open");
+
+DEFINE_string(compaction_fadvice, "NORMAL",
+              "Access pattern advice when a file is compacted");
+static auto FLAGS_compaction_fadvice_e =
+  rocksdb::Options().access_hint_on_compaction_start;
+
+DEFINE_bool(use_tailing_iterator, false,
+            "Use tailing iterator to access a series of keys instead of get");
+
+DEFINE_bool(use_adaptive_mutex, rocksdb::Options().use_adaptive_mutex,
+            "Use adaptive mutex");
+
+DEFINE_uint64(bytes_per_sync,  rocksdb::Options().bytes_per_sync,
+              "Allows OS to incrementally sync SST files to disk while they are"
+              " being written, in the background. Issue one request for every"
+              " bytes_per_sync written. 0 turns it off.");
+
+DEFINE_uint64(wal_bytes_per_sync,  rocksdb::Options().wal_bytes_per_sync,
+              "Allows OS to incrementally sync WAL files to disk while they are"
+              " being written, in the background. Issue one request for every"
+              " wal_bytes_per_sync written. 0 turns it off.");
+
+DEFINE_bool(use_single_deletes, true,
+            "Use single deletes (used in RandomReplaceKeys only).");
+
+DEFINE_double(stddev, 2000.0,
+              "Standard deviation of normal distribution used for picking keys"
+              " (used in RandomReplaceKeys only).");
+
+DEFINE_int32(key_id_range, 100000,
+             "Range of possible value of key id (used in TimeSeries only).");
+
+DEFINE_string(expire_style, "none",
+              "Style to remove expired time entries. Can be one of the options "
+              "below: none (do not expired data), compaction_filter (use a "
+              "compaction filter to remove expired data), delete (seek IDs and "
+              "remove expired data) (used in TimeSeries only).");
+
+DEFINE_uint64(
+    time_range, 100000,
+    "Range of timestamp that store in the database (used in TimeSeries"
+    " only).");
+
+DEFINE_int32(num_deletion_threads, 1,
+             "Number of threads to do deletion (used in TimeSeries and delete "
+             "expire_style only).");
+
+DEFINE_int32(max_successive_merges, 0, "Maximum number of successive merge"
+             " operations on a key in the memtable");
+
+static bool ValidatePrefixSize(const char* flagname, int32_t value) {
+  if (value < 0 || value>=2000000000) {
+    fprintf(stderr, "Invalid value for --%s: %d. 0<= PrefixSize <=2000000000\n",
+            flagname, value);
+    return false;
+  }
+  return true;
+}
+DEFINE_int32(prefix_size, 0, "control the prefix size for HashSkipList and "
+             "plain table");
+DEFINE_int64(keys_per_prefix, 0, "control average number of keys generated "
+             "per prefix, 0 means no special handling of the prefix, "
+             "i.e. use the prefix comes with the generated random number.");
+DEFINE_int32(memtable_insert_with_hint_prefix_size, 0,
+             "If non-zero, enable "
+             "memtable insert with hint with the given prefix size.");
+DEFINE_bool(enable_io_prio, false, "Lower the background flush/compaction "
+            "threads' IO priority");
+DEFINE_bool(enable_cpu_prio, false, "Lower the background flush/compaction "
+            "threads' CPU priority");
+DEFINE_bool(identity_as_first_hash, false, "the first hash function of cuckoo "
+            "table becomes an identity function. This is only valid when key "
+            "is 8 bytes");
+DEFINE_bool(dump_malloc_stats, true, "Dump malloc stats in LOG ");
+DEFINE_uint64(stats_dump_period_sec, rocksdb::Options().stats_dump_period_sec,
+              "Gap between printing stats to log in seconds");
+DEFINE_uint64(stats_persist_period_sec,
+              rocksdb::Options().stats_persist_period_sec,
+              "Gap between persisting stats in seconds");
+DEFINE_uint64(stats_history_buffer_size,
+              rocksdb::Options().stats_history_buffer_size,
+              "Max number of stats snapshots to keep in memory");
+
+enum RepFactory {
+  kSkipList,
+  kPrefixHash,
+  kVectorRep,
+  kHashLinkedList,
+};
+
+static enum RepFactory StringToRepFactory(const char* ctype) {
+  assert(ctype);
+
+  if (!strcasecmp(ctype, "skip_list"))
+    return kSkipList;
+  else if (!strcasecmp(ctype, "prefix_hash"))
+    return kPrefixHash;
+  else if (!strcasecmp(ctype, "vector"))
+    return kVectorRep;
+  else if (!strcasecmp(ctype, "hash_linkedlist"))
+    return kHashLinkedList;
+
+  fprintf(stdout, "Cannot parse memreptable %s\n", ctype);
+  return kSkipList;
+}
+
+static enum RepFactory FLAGS_rep_factory;
+DEFINE_string(memtablerep, "skip_list", "");
+DEFINE_int64(hash_bucket_count, 1024 * 1024, "hash bucket count");
+DEFINE_bool(use_plain_table, false, "if use plain table "
+            "instead of block-based table format");
+DEFINE_bool(use_cuckoo_table, false, "if use cuckoo table format");
+DEFINE_double(cuckoo_hash_ratio, 0.9, "Hash ratio for Cuckoo SST table.");
+DEFINE_bool(use_hash_search, false, "if use kHashSearch "
+            "instead of kBinarySearch. "
+            "This is valid if only we use BlockTable");
+DEFINE_bool(use_block_based_filter, false, "if use kBlockBasedFilter "
+            "instead of kFullFilter for filter block. "
+            "This is valid if only we use BlockTable");
+DEFINE_string(merge_operator, "", "The merge operator to use with the database."
+              "If a new merge operator is specified, be sure to use fresh"
+              " database The possible merge operators are defined in"
+              " utilities/merge_operators.h");
+DEFINE_int32(skip_list_lookahead, 0, "Used with skip_list memtablerep; try "
+             "linear search first for this many steps from the previous "
+             "position");
+DEFINE_bool(report_file_operations, false, "if report number of file "
+            "operations");
+
+static const bool FLAGS_soft_rate_limit_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_soft_rate_limit, &ValidateRateLimit);
+
+static const bool FLAGS_hard_rate_limit_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_hard_rate_limit, &ValidateRateLimit);
+
+static const bool FLAGS_prefix_size_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_prefix_size, &ValidatePrefixSize);
+
+static const bool FLAGS_key_size_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_key_size, &ValidateKeySize);
+
+static const bool FLAGS_cache_numshardbits_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_cache_numshardbits,
+                          &ValidateCacheNumshardbits);
+
+static const bool FLAGS_readwritepercent_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_readwritepercent, &ValidateInt32Percent);
+
+DEFINE_int32(disable_seek_compaction, false,
+             "Not used, left here for backwards compatibility");
+
+static const bool FLAGS_deletepercent_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_deletepercent, &ValidateInt32Percent);
+static const bool FLAGS_table_cache_numshardbits_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_table_cache_numshardbits,
+                          &ValidateTableCacheNumshardbits);
+
+namespace rocksdb {
+
+namespace {
+struct ReportFileOpCounters {
+  std::atomic<int> open_counter_;
+  std::atomic<int> read_counter_;
+  std::atomic<int> append_counter_;
+  std::atomic<uint64_t> bytes_read_;
+  std::atomic<uint64_t> bytes_written_;
+};
+
+// A special Env to records and report file operations in db_bench
+class ReportFileOpEnv : public EnvWrapper {
+ public:
+  explicit ReportFileOpEnv(Env* base) : EnvWrapper(base) { reset(); }
+
+  void reset() {
+    counters_.open_counter_ = 0;
+    counters_.read_counter_ = 0;
+    counters_.append_counter_ = 0;
+    counters_.bytes_read_ = 0;
+    counters_.bytes_written_ = 0;
+  }
+
+  Status NewSequentialFile(const std::string& f,
+                           std::unique_ptr<SequentialFile>* r,
+                           const EnvOptions& soptions) override {
+    class CountingFile : public SequentialFile {
+     private:
+      std::unique_ptr<SequentialFile> target_;
+      ReportFileOpCounters* counters_;
+
+     public:
+      CountingFile(std::unique_ptr<SequentialFile>&& target,
+                   ReportFileOpCounters* counters)
+          : target_(std::move(target)), counters_(counters) {}
+
+      Status Read(size_t n, Slice* result, char* scratch) override {
+        counters_->read_counter_.fetch_add(1, std::memory_order_relaxed);
+        Status rv = target_->Read(n, result, scratch);
+        counters_->bytes_read_.fetch_add(result->size(),
+                                         std::memory_order_relaxed);
+        return rv;
+      }
+
+      Status Skip(uint64_t n) override { return target_->Skip(n); }
+    };
+
+    Status s = target()->NewSequentialFile(f, r, soptions);
+    if (s.ok()) {
+      counters()->open_counter_.fetch_add(1, std::memory_order_relaxed);
+      r->reset(new CountingFile(std::move(*r), counters()));
+    }
+    return s;
+  }
+
+  Status NewRandomAccessFile(const std::string& f,
+                             std::unique_ptr<RandomAccessFile>* r,
+                             const EnvOptions& soptions) override {
+    class CountingFile : public RandomAccessFile {
+     private:
+      std::unique_ptr<RandomAccessFile> target_;
+      ReportFileOpCounters* counters_;
+
+     public:
+      CountingFile(std::unique_ptr<RandomAccessFile>&& target,
+                   ReportFileOpCounters* counters)
+          : target_(std::move(target)), counters_(counters) {}
+      Status Read(uint64_t offset, size_t n, Slice* result,
+                  char* scratch) const override {
+        counters_->read_counter_.fetch_add(1, std::memory_order_relaxed);
+        Status rv = target_->Read(offset, n, result, scratch);
+        counters_->bytes_read_.fetch_add(result->size(),
+                                         std::memory_order_relaxed);
+        return rv;
+      }
+    };
+
+    Status s = target()->NewRandomAccessFile(f, r, soptions);
+    if (s.ok()) {
+      counters()->open_counter_.fetch_add(1, std::memory_order_relaxed);
+      r->reset(new CountingFile(std::move(*r), counters()));
+    }
+    return s;
+  }
+
+  Status NewWritableFile(const std::string& f, std::unique_ptr<WritableFile>* r,
+                         const EnvOptions& soptions) override {
+    class CountingFile : public WritableFile {
+     private:
+      std::unique_ptr<WritableFile> target_;
+      ReportFileOpCounters* counters_;
+
+     public:
+      CountingFile(std::unique_ptr<WritableFile>&& target,
+                   ReportFileOpCounters* counters)
+          : target_(std::move(target)), counters_(counters) {}
+
+      Status Append(const Slice& data) override {
+        counters_->append_counter_.fetch_add(1, std::memory_order_relaxed);
+        Status rv = target_->Append(data);
+        counters_->bytes_written_.fetch_add(data.size(),
+                                            std::memory_order_relaxed);
+        return rv;
+      }
+
+      Status Truncate(uint64_t size) override { return target_->Truncate(size); }
+      Status Close() override { return target_->Close(); }
+      Status Flush() override { return target_->Flush(); }
+      Status Sync() override { return target_->Sync(); }
+    };
+
+    Status s = target()->NewWritableFile(f, r, soptions);
+    if (s.ok()) {
+      counters()->open_counter_.fetch_add(1, std::memory_order_relaxed);
+      r->reset(new CountingFile(std::move(*r), counters()));
+    }
+    return s;
+  }
+
+  // getter
+  ReportFileOpCounters* counters() { return &counters_; }
+
+ private:
+  ReportFileOpCounters counters_;
+};
+
+}  // namespace
+
+// Helper for quickly generating random data.
+class RandomGenerator {
+ private:
+  std::string data_;
+  unsigned int pos_;
+
+ public:
+  RandomGenerator() {
+    // We use a limited amount of data over and over again and ensure
+    // that it is larger than the compression window (32KB), and also
+    // large enough to serve all typical value sizes we want to write.
+    Random rnd(301);
+    std::string piece;
+    while (data_.size() < (unsigned)std::max(1048576, FLAGS_value_size)) {
+      // Add a short fragment that is as compressible as specified
+      // by FLAGS_compression_ratio.
+      test::CompressibleString(&rnd, FLAGS_compression_ratio, 100, &piece);
+      data_.append(piece);
+    }
+    pos_ = 0;
+  }
+
+  Slice Generate(unsigned int len) {
+    assert(len <= data_.size());
+    if (pos_ + len > data_.size()) {
+      pos_ = 0;
+    }
+    pos_ += len;
+    return Slice(data_.data() + pos_ - len, len);
+  }
+
+  Slice GenerateWithTTL(unsigned int len) {
+    assert(len <= data_.size());
+    if (pos_ + len > data_.size()) {
+      pos_ = 0;
+    }
+    pos_ += len;
+    return Slice(data_.data() + pos_ - len, len);
+  }
+};
+
+static void AppendWithSpace(std::string* str, Slice msg) {
+  if (msg.empty()) return;
+  if (!str->empty()) {
+    str->push_back(' ');
+  }
+  str->append(msg.data(), msg.size());
+}
+
+struct DBWithColumnFamilies {
+  std::vector<ColumnFamilyHandle*> cfh;
+  DB* db;
+#ifndef ROCKSDB_LITE
+  OptimisticTransactionDB* opt_txn_db;
+#endif  // ROCKSDB_LITE
+  std::atomic<size_t> num_created;  // Need to be updated after all the
+                                    // new entries in cfh are set.
+  size_t num_hot;  // Number of column families to be queried at each moment.
+                   // After each CreateNewCf(), another num_hot number of new
+                   // Column families will be created and used to be queried.
+  port::Mutex create_cf_mutex;  // Only one thread can execute CreateNewCf()
+  std::vector<int> cfh_idx_to_prob;  // ith index holds probability of operating
+                                     // on cfh[i].
+
+  DBWithColumnFamilies()
+      : db(nullptr)
+#ifndef ROCKSDB_LITE
+        , opt_txn_db(nullptr)
+#endif  // ROCKSDB_LITE
+  {
+    cfh.clear();
+    num_created = 0;
+    num_hot = 0;
+  }
+
+  DBWithColumnFamilies(const DBWithColumnFamilies& other)
+      : cfh(other.cfh),
+        db(other.db),
+#ifndef ROCKSDB_LITE
+        opt_txn_db(other.opt_txn_db),
+#endif  // ROCKSDB_LITE
+        num_created(other.num_created.load()),
+        num_hot(other.num_hot),
+        cfh_idx_to_prob(other.cfh_idx_to_prob) {
+  }
+
+  void DeleteDBs() {
+    std::for_each(cfh.begin(), cfh.end(),
+                  [](ColumnFamilyHandle* cfhi) { delete cfhi; });
+    cfh.clear();
+#ifndef ROCKSDB_LITE
+    if (opt_txn_db) {
+      delete opt_txn_db;
+      opt_txn_db = nullptr;
+    } else {
+      delete db;
+      db = nullptr;
+    }
+#else
+    delete db;
+    db = nullptr;
+#endif  // ROCKSDB_LITE
+  }
+
+  ColumnFamilyHandle* GetCfh(int64_t rand_num) {
+    assert(num_hot > 0);
+    size_t rand_offset = 0;
+    if (!cfh_idx_to_prob.empty()) {
+      assert(cfh_idx_to_prob.size() == num_hot);
+      int sum = 0;
+      while (sum + cfh_idx_to_prob[rand_offset] < rand_num % 100) {
+        sum += cfh_idx_to_prob[rand_offset];
+        ++rand_offset;
+      }
+      assert(rand_offset < cfh_idx_to_prob.size());
+    } else {
+      rand_offset = rand_num % num_hot;
+    }
+    return cfh[num_created.load(std::memory_order_acquire) - num_hot +
+               rand_offset];
+  }
+
+  // stage: assume CF from 0 to stage * num_hot has be created. Need to create
+  //        stage * num_hot + 1 to stage * (num_hot + 1).
+  void CreateNewCf(ColumnFamilyOptions options, int64_t stage) {
+    MutexLock l(&create_cf_mutex);
+    if ((stage + 1) * num_hot <= num_created) {
+      // Already created.
+      return;
+    }
+    auto new_num_created = num_created + num_hot;
+    assert(new_num_created <= cfh.size());
+    for (size_t i = num_created; i < new_num_created; i++) {
+      Status s =
+          db->CreateColumnFamily(options, ColumnFamilyName(i), &(cfh[i]));
+      if (!s.ok()) {
+        fprintf(stderr, "create column family error: %s\n",
+                s.ToString().c_str());
+        abort();
+      }
+    }
+    num_created.store(new_num_created, std::memory_order_release);
+  }
+};
+
+// a class that reports stats to CSV file
+class ReporterAgent {
+ public:
+  ReporterAgent(Env* env, const std::string& fname,
+                uint64_t report_interval_secs)
+      : env_(env),
+        total_ops_done_(0),
+        last_report_(0),
+        report_interval_secs_(report_interval_secs),
+        stop_(false) {
+    auto s = env_->NewWritableFile(fname, &report_file_, EnvOptions());
+    if (s.ok()) {
+      s = report_file_->Append(Header() + "\n");
+    }
+    if (s.ok()) {
+      s = report_file_->Flush();
+    }
+    if (!s.ok()) {
+      fprintf(stderr, "Can't open %s: %s\n", fname.c_str(),
+              s.ToString().c_str());
+      abort();
+    }
+
+    reporting_thread_ = port::Thread([&]() { SleepAndReport(); });
+  }
+
+  ~ReporterAgent() {
+    {
+      std::unique_lock<std::mutex> lk(mutex_);
+      stop_ = true;
+      stop_cv_.notify_all();
+    }
+    reporting_thread_.join();
+  }
+
+  // thread safe
+  void ReportFinishedOps(int64_t num_ops) {
+    total_ops_done_.fetch_add(num_ops);
+  }
+
+ private:
+  std::string Header() const { return "secs_elapsed,interval_qps"; }
+  void SleepAndReport() {
+    uint64_t kMicrosInSecond = 1000 * 1000;
+    auto time_started = env_->NowMicros();
+    while (true) {
+      {
+        std::unique_lock<std::mutex> lk(mutex_);
+        if (stop_ ||
+            stop_cv_.wait_for(lk, std::chrono::seconds(report_interval_secs_),
+                              [&]() { return stop_; })) {
+          // stopping
+          break;
+        }
+        // else -> timeout, which means time for a report!
+      }
+      auto total_ops_done_snapshot = total_ops_done_.load();
+      // round the seconds elapsed
+      auto secs_elapsed =
+          (env_->NowMicros() - time_started + kMicrosInSecond / 2) /
+          kMicrosInSecond;
+      std::string report = ToString(secs_elapsed) + "," +
+                           ToString(total_ops_done_snapshot - last_report_) +
+                           "\n";
+      auto s = report_file_->Append(report);
+      if (s.ok()) {
+        s = report_file_->Flush();
+      }
+      if (!s.ok()) {
+        fprintf(stderr,
+                "Can't write to report file (%s), stopping the reporting\n",
+                s.ToString().c_str());
+        break;
+      }
+      last_report_ = total_ops_done_snapshot;
+    }
+  }
+
+  Env* env_;
+  std::unique_ptr<WritableFile> report_file_;
+  std::atomic<int64_t> total_ops_done_;
+  int64_t last_report_;
+  const uint64_t report_interval_secs_;
+  rocksdb::port::Thread reporting_thread_;
+  std::mutex mutex_;
+  // will notify on stop
+  std::condition_variable stop_cv_;
+  bool stop_;
+};
+
+enum OperationType : unsigned char {
+  kRead = 0,
+  kWrite,
+  kDelete,
+  kSeek,
+  kMerge,
+  kUpdate,
+  kCompress,
+  kUncompress,
+  kCrc,
+  kHash,
+  kOthers
+};
+
+static std::unordered_map<OperationType, std::string, std::hash<unsigned char>>
+                          OperationTypeString = {
+  {kRead, "read"},
+  {kWrite, "write"},
+  {kDelete, "delete"},
+  {kSeek, "seek"},
+  {kMerge, "merge"},
+  {kUpdate, "update"},
+  {kCompress, "compress"},
+  {kCompress, "uncompress"},
+  {kCrc, "crc"},
+  {kHash, "hash"},
+  {kOthers, "op"}
+};
+
+class CombinedStats;
+class Stats {
+ private:
+  int id_;
+  uint64_t start_;
+  uint64_t sine_interval_;
+  uint64_t finish_;
+  double seconds_;
+  uint64_t done_;
+  uint64_t last_report_done_;
+  uint64_t next_report_;
+  uint64_t bytes_;
+  uint64_t last_op_finish_;
+  uint64_t last_report_finish_;
+  std::unordered_map<OperationType, std::shared_ptr<HistogramImpl>,
+                     std::hash<unsigned char>> hist_;
+  std::string message_;
+  bool exclude_from_merge_;
+  ReporterAgent* reporter_agent_;  // does not own
+  friend class CombinedStats;
+
+ public:
+  Stats() { Start(-1); }
+
+  void SetReporterAgent(ReporterAgent* reporter_agent) {
+    reporter_agent_ = reporter_agent;
+  }
+
+  void Start(int id) {
+    id_ = id;
+    next_report_ = FLAGS_stats_interval ? FLAGS_stats_interval : 100;
+    last_op_finish_ = start_;
+    hist_.clear();
+    done_ = 0;
+    last_report_done_ = 0;
+    bytes_ = 0;
+    seconds_ = 0;
+    start_ = FLAGS_env->NowMicros();
+    sine_interval_ = FLAGS_env->NowMicros();
+    finish_ = start_;
+    last_report_finish_ = start_;
+    message_.clear();
+    // When set, stats from this thread won't be merged with others.
+    exclude_from_merge_ = false;
+  }
+
+  void Merge(const Stats& other) {
+    if (other.exclude_from_merge_)
+      return;
+
+    for (auto it = other.hist_.begin(); it != other.hist_.end(); ++it) {
+      auto this_it = hist_.find(it->first);
+      if (this_it != hist_.end()) {
+        this_it->second->Merge(*(other.hist_.at(it->first)));
+      } else {
+        hist_.insert({ it->first, it->second });
+      }
+    }
+
+    done_ += other.done_;
+    bytes_ += other.bytes_;
+    seconds_ += other.seconds_;
+    if (other.start_ < start_) start_ = other.start_;
+    if (other.finish_ > finish_) finish_ = other.finish_;
+
+    // Just keep the messages from one thread
+    if (message_.empty()) message_ = other.message_;
+  }
+
+  void Stop() {
+    finish_ = FLAGS_env->NowMicros();
+    seconds_ = (finish_ - start_) * 1e-6;
+  }
+
+  void AddMessage(Slice msg) {
+    AppendWithSpace(&message_, msg);
+  }
+
+  void SetId(int id) { id_ = id; }
+  void SetExcludeFromMerge() { exclude_from_merge_ = true; }
+
+  void PrintThreadStatus() {
+    std::vector<ThreadStatus> thread_list;
+    FLAGS_env->GetThreadList(&thread_list);
+
+    fprintf(stderr, "\n%18s %10s %12s %20s %13s %45s %12s %s\n",
+        "ThreadID", "ThreadType", "cfName", "Operation",
+        "ElapsedTime", "Stage", "State", "OperationProperties");
+
+    int64_t current_time = 0;
+    Env::Default()->GetCurrentTime(&current_time);
+    for (auto ts : thread_list) {
+      fprintf(stderr, "%18" PRIu64 " %10s %12s %20s %13s %45s %12s",
+          ts.thread_id,
+          ThreadStatus::GetThreadTypeName(ts.thread_type).c_str(),
+          ts.cf_name.c_str(),
+          ThreadStatus::GetOperationName(ts.operation_type).c_str(),
+          ThreadStatus::MicrosToString(ts.op_elapsed_micros).c_str(),
+          ThreadStatus::GetOperationStageName(ts.operation_stage).c_str(),
+          ThreadStatus::GetStateName(ts.state_type).c_str());
+
+      auto op_properties = ThreadStatus::InterpretOperationProperties(
+          ts.operation_type, ts.op_properties);
+      for (const auto& op_prop : op_properties) {
+        fprintf(stderr, " %s %" PRIu64" |",
+            op_prop.first.c_str(), op_prop.second);
+      }
+      fprintf(stderr, "\n");
+    }
+  }
+
+  void ResetSineInterval() {
+    sine_interval_ = FLAGS_env->NowMicros();
+  }
+
+  uint64_t GetSineInterval() {
+    return sine_interval_;
+  }
+
+  uint64_t GetStart() {
+    return start_;
+  }
+
+  void ResetLastOpTime() {
+    // Set to now to avoid latency from calls to SleepForMicroseconds
+    last_op_finish_ = FLAGS_env->NowMicros();
+  }
+
+  void FinishedOps(DBWithColumnFamilies* db_with_cfh, DB* db, int64_t num_ops,
+                   enum OperationType op_type = kOthers) {
+    if (reporter_agent_) {
+      reporter_agent_->ReportFinishedOps(num_ops);
+    }
+    if (FLAGS_histogram) {
+      uint64_t now = FLAGS_env->NowMicros();
+      uint64_t micros = now - last_op_finish_;
+
+      if (hist_.find(op_type) == hist_.end())
+      {
+        auto hist_temp = std::make_shared<HistogramImpl>();
+        hist_.insert({op_type, std::move(hist_temp)});
+      }
+      hist_[op_type]->Add(micros);
+
+      if (micros > 20000 && !FLAGS_stats_interval) {
+        fprintf(stderr, "long op: %" PRIu64 " micros%30s\r", micros, "");
+        fflush(stderr);
+      }
+      last_op_finish_ = now;
+    }
+
+    done_ += num_ops;
+    if (done_ >= next_report_) {
+      if (!FLAGS_stats_interval) {
+        if      (next_report_ < 1000)   next_report_ += 100;
+        else if (next_report_ < 5000)   next_report_ += 500;
+        else if (next_report_ < 10000)  next_report_ += 1000;
+        else if (next_report_ < 50000)  next_report_ += 5000;
+        else if (next_report_ < 100000) next_report_ += 10000;
+        else if (next_report_ < 500000) next_report_ += 50000;
+        else                            next_report_ += 100000;
+        fprintf(stderr, "... finished %" PRIu64 " ops%30s\r", done_, "");
+      } else {
+        uint64_t now = FLAGS_env->NowMicros();
+        int64_t usecs_since_last = now - last_report_finish_;
+
+        // Determine whether to print status where interval is either
+        // each N operations or each N seconds.
+
+        if (FLAGS_stats_interval_seconds &&
+            usecs_since_last < (FLAGS_stats_interval_seconds * 1000000)) {
+          // Don't check again for this many operations
+          next_report_ += FLAGS_stats_interval;
+
+        } else {
+
+          fprintf(stderr,
+                  "%s ... thread %d: (%" PRIu64 ",%" PRIu64 ") ops and "
+                  "(%.1f,%.1f) ops/second in (%.6f,%.6f) seconds\n",
+                  FLAGS_env->TimeToString(now/1000000).c_str(),
+                  id_,
+                  done_ - last_report_done_, done_,
+                  (done_ - last_report_done_) /
+                  (usecs_since_last / 1000000.0),
+                  done_ / ((now - start_) / 1000000.0),
+                  (now - last_report_finish_) / 1000000.0,
+                  (now - start_) / 1000000.0);
+
+          if (id_ == 0 && FLAGS_stats_per_interval) {
+            std::string stats;
+
+            if (db_with_cfh && db_with_cfh->num_created.load()) {
+              for (size_t i = 0; i < db_with_cfh->num_created.load(); ++i) {
+                if (db->GetProperty(db_with_cfh->cfh[i], "rocksdb.cfstats",
+                                    &stats))
+                  fprintf(stderr, "%s\n", stats.c_str());
+                if (FLAGS_show_table_properties) {
+                  for (int level = 0; level < FLAGS_num_levels; ++level) {
+                    if (db->GetProperty(
+                            db_with_cfh->cfh[i],
+                            "rocksdb.aggregated-table-properties-at-level" +
+                                ToString(level),
+                            &stats)) {
+                      if (stats.find("# entries=0") == std::string::npos) {
+                        fprintf(stderr, "Level[%d]: %s\n", level,
+                                stats.c_str());
+                      }
+                    }
+                  }
+                }
+              }
+            } else if (db) {
+              if (db->GetProperty("rocksdb.stats", &stats)) {
+                fprintf(stderr, "%s\n", stats.c_str());
+              }
+              if (FLAGS_show_table_properties) {
+                for (int level = 0; level < FLAGS_num_levels; ++level) {
+                  if (db->GetProperty(
+                          "rocksdb.aggregated-table-properties-at-level" +
+                              ToString(level),
+                          &stats)) {
+                    if (stats.find("# entries=0") == std::string::npos) {
+                      fprintf(stderr, "Level[%d]: %s\n", level, stats.c_str());
+                    }
+                  }
+                }
+              }
+            }
+          }
+
+          next_report_ += FLAGS_stats_interval;
+          last_report_finish_ = now;
+          last_report_done_ = done_;
+        }
+      }
+      if (id_ == 0 && FLAGS_thread_status_per_interval) {
+        PrintThreadStatus();
+      }
+      fflush(stderr);
+    }
+  }
+
+  void AddBytes(int64_t n) {
+    bytes_ += n;
+  }
+
+  void Report(const Slice& name) {
+    // Pretend at least one op was done in case we are running a benchmark
+    // that does not call FinishedOps().
+    if (done_ < 1) done_ = 1;
+
+    std::string extra;
+    if (bytes_ > 0) {
+      // Rate is computed on actual elapsed time, not the sum of per-thread
+      // elapsed times.
+      double elapsed = (finish_ - start_) * 1e-6;
+      char rate[100];
+      snprintf(rate, sizeof(rate), "%6.1f MB/s",
+               (bytes_ / 1048576.0) / elapsed);
+      extra = rate;
+    }
+    AppendWithSpace(&extra, message_);
+    double elapsed = (finish_ - start_) * 1e-6;
+    double throughput = (double)done_/elapsed;
+
+    fprintf(stdout, "%-12s : %11.3f micros/op %ld ops/sec;%s%s\n",
+            name.ToString().c_str(),
+            seconds_ * 1e6 / done_,
+            (long)throughput,
+            (extra.empty() ? "" : " "),
+            extra.c_str());
+    if (FLAGS_histogram) {
+      for (auto it = hist_.begin(); it != hist_.end(); ++it) {
+        fprintf(stdout, "Microseconds per %s:\n%s\n",
+                OperationTypeString[it->first].c_str(),
+                it->second->ToString().c_str());
+      }
+    }
+    if (FLAGS_report_file_operations) {
+      ReportFileOpEnv* env = static_cast<ReportFileOpEnv*>(FLAGS_env);
+      ReportFileOpCounters* counters = env->counters();
+      fprintf(stdout, "Num files opened: %d\n",
+              counters->open_counter_.load(std::memory_order_relaxed));
+      fprintf(stdout, "Num Read(): %d\n",
+              counters->read_counter_.load(std::memory_order_relaxed));
+      fprintf(stdout, "Num Append(): %d\n",
+              counters->append_counter_.load(std::memory_order_relaxed));
+      fprintf(stdout, "Num bytes read: %" PRIu64 "\n",
+              counters->bytes_read_.load(std::memory_order_relaxed));
+      fprintf(stdout, "Num bytes written: %" PRIu64 "\n",
+              counters->bytes_written_.load(std::memory_order_relaxed));
+      env->reset();
+    }
+    fflush(stdout);
+  }
+};
+
+class CombinedStats {
+ public:
+  void AddStats(const Stats& stat) {
+    uint64_t total_ops = stat.done_;
+    uint64_t total_bytes_ = stat.bytes_;
+    double elapsed;
+
+    if (total_ops < 1) {
+      total_ops = 1;
+    }
+
+    elapsed = (stat.finish_ - stat.start_) * 1e-6;
+    throughput_ops_.emplace_back(total_ops / elapsed);
+
+    if (total_bytes_ > 0) {
+      double mbs = (total_bytes_ / 1048576.0);
+      throughput_mbs_.emplace_back(mbs / elapsed);
+    }
+  }
+
+  void Report(const std::string& bench_name) {
+    const char* name = bench_name.c_str();
+    int num_runs = static_cast<int>(throughput_ops_.size());
+
+    if (throughput_mbs_.size() == throughput_ops_.size()) {
+      fprintf(stdout,
+              "%s [AVG    %d runs] : %d ops/sec; %6.1f MB/sec\n"
+              "%s [MEDIAN %d runs] : %d ops/sec; %6.1f MB/sec\n",
+              name, num_runs, static_cast<int>(CalcAvg(throughput_ops_)),
+              CalcAvg(throughput_mbs_), name, num_runs,
+              static_cast<int>(CalcMedian(throughput_ops_)),
+              CalcMedian(throughput_mbs_));
+    } else {
+      fprintf(stdout,
+              "%s [AVG    %d runs] : %d ops/sec\n"
+              "%s [MEDIAN %d runs] : %d ops/sec\n",
+              name, num_runs, static_cast<int>(CalcAvg(throughput_ops_)), name,
+              num_runs, static_cast<int>(CalcMedian(throughput_ops_)));
+    }
+  }
+
+ private:
+  double CalcAvg(std::vector<double> data) {
+    double avg = 0;
+    for (double x : data) {
+      avg += x;
+    }
+    avg = avg / data.size();
+    return avg;
+  }
+
+  double CalcMedian(std::vector<double> data) {
+    assert(data.size() > 0);
+    std::sort(data.begin(), data.end());
+
+    size_t mid = data.size() / 2;
+    if (data.size() % 2 == 1) {
+      // Odd number of entries
+      return data[mid];
+    } else {
+      // Even number of entries
+      return (data[mid] + data[mid - 1]) / 2;
+    }
+  }
+
+  std::vector<double> throughput_ops_;
+  std::vector<double> throughput_mbs_;
+};
+
+class TimestampEmulator {
+ private:
+  std::atomic<uint64_t> timestamp_;
+
+ public:
+  TimestampEmulator() : timestamp_(0) {}
+  uint64_t Get() const { return timestamp_.load(); }
+  void Inc() { timestamp_++; }
+};
+
+// State shared by all concurrent executions of the same benchmark.
+struct SharedState {
+  port::Mutex mu;
+  port::CondVar cv;
+  int total;
+  int perf_level;
+  std::shared_ptr<RateLimiter> write_rate_limiter;
+  std::shared_ptr<RateLimiter> read_rate_limiter;
+
+  // Each thread goes through the following states:
+  //    (1) initializing
+  //    (2) waiting for others to be initialized
+  //    (3) running
+  //    (4) done
+
+  long num_initialized;
+  long num_done;
+  bool start;
+
+  SharedState() : cv(&mu), perf_level(FLAGS_perf_level) { }
+};
+
+// Per-thread state for concurrent executions of the same benchmark.
+struct ThreadState {
+  int tid;             // 0..n-1 when running in n threads
+  Random64 rand;         // Has different seeds for different threads
+  Stats stats;
+  SharedState* shared;
+
+  /* implicit */ ThreadState(int index)
+      : tid(index),
+        rand((FLAGS_seed ? FLAGS_seed : 1000) + index) {
+  }
+};
+
+class Duration {
+ public:
+  Duration(uint64_t max_seconds, int64_t max_ops, int64_t ops_per_stage = 0) {
+    max_seconds_ = max_seconds;
+    max_ops_= max_ops;
+    ops_per_stage_ = (ops_per_stage > 0) ? ops_per_stage : max_ops;
+    ops_ = 0;
+    start_at_ = FLAGS_env->NowMicros();
+  }
+
+  int64_t GetStage() { return std::min(ops_, max_ops_ - 1) / ops_per_stage_; }
+
+  bool Done(int64_t increment) {
+    if (increment <= 0) increment = 1;    // avoid Done(0) and infinite loops
+    ops_ += increment;
+
+    if (max_seconds_) {
+      // Recheck every appx 1000 ops (exact iff increment is factor of 1000)
+      auto granularity = FLAGS_ops_between_duration_checks;
+      if ((ops_ / granularity) != ((ops_ - increment) / granularity)) {
+        uint64_t now = FLAGS_env->NowMicros();
+        return ((now - start_at_) / 1000000) >= max_seconds_;
+      } else {
+        return false;
+      }
+    } else {
+      return ops_ > max_ops_;
+    }
+  }
+
+ private:
+  uint64_t max_seconds_;
+  int64_t max_ops_;
+  int64_t ops_per_stage_;
+  int64_t ops_;
+  uint64_t start_at_;
+};
+
+class Benchmark {
+ private:
+  std::shared_ptr<Cache> cache_;
+  std::shared_ptr<Cache> compressed_cache_;
+  std::shared_ptr<const FilterPolicy> filter_policy_;
+  const SliceTransform* prefix_extractor_;
+  DBWithColumnFamilies db_;
+  std::vector<DBWithColumnFamilies> multi_dbs_;
+  int64_t num_;
+  int value_size_;
+  int key_size_;
+  int prefix_size_;
+  int64_t keys_per_prefix_;
+  int64_t entries_per_batch_;
+  int64_t writes_before_delete_range_;
+  int64_t writes_per_range_tombstone_;
+  int64_t range_tombstone_width_;
+  int64_t max_num_range_tombstones_;
+  WriteOptions write_options_;
+  Options open_options_;  // keep options around to properly destroy db later
+#ifndef ROCKSDB_LITE
+  TraceOptions trace_options_;
+#endif
+  int64_t reads_;
+  int64_t deletes_;
+  double read_random_exp_range_;
+  int64_t writes_;
+  int64_t readwrites_;
+  int64_t merge_keys_;
+  bool report_file_operations_;
+  bool use_blob_db_;
+  std::vector<std::string> keys_;
+
+  class ErrorHandlerListener : public EventListener {
+   public:
+#ifndef ROCKSDB_LITE
+    ErrorHandlerListener()
+        : mutex_(),
+          cv_(&mutex_),
+          no_auto_recovery_(false),
+          recovery_complete_(false) {}
+
+    ~ErrorHandlerListener() override {}
+
+    void OnErrorRecoveryBegin(BackgroundErrorReason /*reason*/,
+                              Status /*bg_error*/,
+                              bool* auto_recovery) override {
+      if (*auto_recovery && no_auto_recovery_) {
+        *auto_recovery = false;
+      }
+    }
+
+    void OnErrorRecoveryCompleted(Status /*old_bg_error*/) override {
+      InstrumentedMutexLock l(&mutex_);
+      recovery_complete_ = true;
+      cv_.SignalAll();
+    }
+
+    bool WaitForRecovery(uint64_t /*abs_time_us*/) {
+      InstrumentedMutexLock l(&mutex_);
+      if (!recovery_complete_) {
+        cv_.Wait(/*abs_time_us*/);
+      }
+      if (recovery_complete_) {
+        recovery_complete_ = false;
+        return true;
+      }
+      return false;
+    }
+
+    void EnableAutoRecovery(bool enable = true) { no_auto_recovery_ = !enable; }
+
+   private:
+    InstrumentedMutex mutex_;
+    InstrumentedCondVar cv_;
+    bool no_auto_recovery_;
+    bool recovery_complete_;
+#else   // ROCKSDB_LITE
+    bool WaitForRecovery(uint64_t /*abs_time_us*/) { return true; }
+    void EnableAutoRecovery(bool /*enable*/) {}
+#endif  // ROCKSDB_LITE
+  };
+
+  std::shared_ptr<ErrorHandlerListener> listener_;
+
+  bool SanityCheck() {
+    if (FLAGS_compression_ratio > 1) {
+      fprintf(stderr, "compression_ratio should be between 0 and 1\n");
+      return false;
+    }
+    return true;
+  }
+
+  inline bool CompressSlice(const CompressionInfo& compression_info,
+                            const Slice& input, std::string* compressed) {
+    bool ok = true;
+    switch (FLAGS_compression_type_e) {
+      case rocksdb::kSnappyCompression:
+        ok = Snappy_Compress(compression_info, input.data(), input.size(),
+                             compressed);
+        break;
+      case rocksdb::kZlibCompression:
+        ok = Zlib_Compress(compression_info, 2, input.data(), input.size(),
+                           compressed);
+        break;
+      case rocksdb::kBZip2Compression:
+        ok = BZip2_Compress(compression_info, 2, input.data(), input.size(),
+                            compressed);
+        break;
+      case rocksdb::kLZ4Compression:
+        ok = LZ4_Compress(compression_info, 2, input.data(), input.size(),
+                          compressed);
+        break;
+      case rocksdb::kLZ4HCCompression:
+        ok = LZ4HC_Compress(compression_info, 2, input.data(), input.size(),
+                            compressed);
+        break;
+      case rocksdb::kXpressCompression:
+        ok = XPRESS_Compress(input.data(),
+          input.size(), compressed);
+        break;
+      case rocksdb::kZSTD:
+        ok = ZSTD_Compress(compression_info, input.data(), input.size(),
+                           compressed);
+        break;
+      default:
+        ok = false;
+    }
+    return ok;
+  }
+
+  void PrintHeader() {
+    PrintEnvironment();
+    fprintf(stdout, "Keys:       %d bytes each\n", FLAGS_key_size);
+    fprintf(stdout, "Values:     %d bytes each (%d bytes after compression)\n",
+            FLAGS_value_size,
+            static_cast<int>(FLAGS_value_size * FLAGS_compression_ratio + 0.5));
+    fprintf(stdout, "Entries:    %" PRIu64 "\n", num_);
+    fprintf(stdout, "Prefix:    %d bytes\n", FLAGS_prefix_size);
+    fprintf(stdout, "Keys per prefix:    %" PRIu64 "\n", keys_per_prefix_);
+    fprintf(stdout, "RawSize:    %.1f MB (estimated)\n",
+            ((static_cast<int64_t>(FLAGS_key_size + FLAGS_value_size) * num_)
+             / 1048576.0));
+    fprintf(stdout, "FileSize:   %.1f MB (estimated)\n",
+            (((FLAGS_key_size + FLAGS_value_size * FLAGS_compression_ratio)
+              * num_)
+             / 1048576.0));
+    fprintf(stdout, "Write rate: %" PRIu64 " bytes/second\n",
+            FLAGS_benchmark_write_rate_limit);
+    fprintf(stdout, "Read rate: %" PRIu64 " ops/second\n",
+            FLAGS_benchmark_read_rate_limit);
+    if (FLAGS_enable_numa) {
+      fprintf(stderr, "Running in NUMA enabled mode.\n");
+#ifndef NUMA
+      fprintf(stderr, "NUMA is not defined in the system.\n");
+      exit(1);
+#else
+      if (numa_available() == -1) {
+        fprintf(stderr, "NUMA is not supported by the system.\n");
+        exit(1);
+      }
+#endif
+    }
+
+    auto compression = CompressionTypeToString(FLAGS_compression_type_e);
+    fprintf(stdout, "Compression: %s\n", compression.c_str());
+    fprintf(stdout, "Compression sampling rate: %" PRId64 "\n",
+            FLAGS_sample_for_compression);
+
+    switch (FLAGS_rep_factory) {
+      case kPrefixHash:
+        fprintf(stdout, "Memtablerep: prefix_hash\n");
+        break;
+      case kSkipList:
+        fprintf(stdout, "Memtablerep: skip_list\n");
+        break;
+      case kVectorRep:
+        fprintf(stdout, "Memtablerep: vector\n");
+        break;
+      case kHashLinkedList:
+        fprintf(stdout, "Memtablerep: hash_linkedlist\n");
+        break;
+    }
+    fprintf(stdout, "Perf Level: %d\n", FLAGS_perf_level);
+
+    PrintWarnings(compression.c_str());
+    fprintf(stdout, "------------------------------------------------\n");
+  }
+
+  void PrintWarnings(const char* compression) {
+#if defined(__GNUC__) && !defined(__OPTIMIZE__)
+    fprintf(stdout,
+            "WARNING: Optimization is disabled: benchmarks unnecessarily slow\n"
+            );
+#endif
+#ifndef NDEBUG
+    fprintf(stdout,
+            "WARNING: Assertions are enabled; benchmarks unnecessarily slow\n");
+#endif
+    if (FLAGS_compression_type_e != rocksdb::kNoCompression) {
+      // The test string should not be too small.
+      const int len = FLAGS_block_size;
+      std::string input_str(len, 'y');
+      std::string compressed;
+      CompressionOptions opts;
+      CompressionContext context(FLAGS_compression_type_e);
+      CompressionInfo info(opts, context, CompressionDict::GetEmptyDict(),
+                           FLAGS_compression_type_e,
+                           FLAGS_sample_for_compression);
+      bool result = CompressSlice(info, Slice(input_str), &compressed);
+
+      if (!result) {
+        fprintf(stdout, "WARNING: %s compression is not enabled\n",
+                compression);
+      } else if (compressed.size() >= input_str.size()) {
+        fprintf(stdout, "WARNING: %s compression is not effective\n",
+                compression);
+      }
+    }
+  }
+
+// Current the following isn't equivalent to OS_LINUX.
+#if defined(__linux)
+  static Slice TrimSpace(Slice s) {
+    unsigned int start = 0;
+    while (start < s.size() && isspace(s[start])) {
+      start++;
+    }
+    unsigned int limit = static_cast<unsigned int>(s.size());
+    while (limit > start && isspace(s[limit-1])) {
+      limit--;
+    }
+    return Slice(s.data() + start, limit - start);
+  }
+#endif
+
+  void PrintEnvironment() {
+    fprintf(stderr, "RocksDB:    version %d.%d\n",
+            kMajorVersion, kMinorVersion);
+
+#if defined(__linux)
+    time_t now = time(nullptr);
+    char buf[52];
+    // Lint complains about ctime() usage, so replace it with ctime_r(). The
+    // requirement is to provide a buffer which is at least 26 bytes.
+    fprintf(stderr, "Date:       %s",
+            ctime_r(&now, buf));  // ctime_r() adds newline
+
+    FILE* cpuinfo = fopen("/proc/cpuinfo", "r");
+    if (cpuinfo != nullptr) {
+      char line[1000];
+      int num_cpus = 0;
+      std::string cpu_type;
+      std::string cache_size;
+      while (fgets(line, sizeof(line), cpuinfo) != nullptr) {
+        const char* sep = strchr(line, ':');
+        if (sep == nullptr) {
+          continue;
+        }
+        Slice key = TrimSpace(Slice(line, sep - 1 - line));
+        Slice val = TrimSpace(Slice(sep + 1));
+        if (key == "model name") {
+          ++num_cpus;
+          cpu_type = val.ToString();
+        } else if (key == "cache size") {
+          cache_size = val.ToString();
+        }
+      }
+      fclose(cpuinfo);
+      fprintf(stderr, "CPU:        %d * %s\n", num_cpus, cpu_type.c_str());
+      fprintf(stderr, "CPUCache:   %s\n", cache_size.c_str());
+    }
+#endif
+  }
+
+  static bool KeyExpired(const TimestampEmulator* timestamp_emulator,
+                         const Slice& key) {
+    const char* pos = key.data();
+    pos += 8;
+    uint64_t timestamp = 0;
+    if (port::kLittleEndian) {
+      int bytes_to_fill = 8;
+      for (int i = 0; i < bytes_to_fill; ++i) {
+        timestamp |= (static_cast<uint64_t>(static_cast<unsigned char>(pos[i]))
+                      << ((bytes_to_fill - i - 1) << 3));
+      }
+    } else {
+      memcpy(&timestamp, pos, sizeof(timestamp));
+    }
+    return timestamp_emulator->Get() - timestamp > FLAGS_time_range;
+  }
+
+  class ExpiredTimeFilter : public CompactionFilter {
+   public:
+    explicit ExpiredTimeFilter(
+        const std::shared_ptr<TimestampEmulator>& timestamp_emulator)
+        : timestamp_emulator_(timestamp_emulator) {}
+    bool Filter(int /*level*/, const Slice& key,
+                const Slice& /*existing_value*/, std::string* /*new_value*/,
+                bool* /*value_changed*/) const override {
+      return KeyExpired(timestamp_emulator_.get(), key);
+    }
+    const char* Name() const override { return "ExpiredTimeFilter"; }
+
+   private:
+    std::shared_ptr<TimestampEmulator> timestamp_emulator_;
+  };
+
+  class KeepFilter : public CompactionFilter {
+   public:
+    bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
+                std::string* /*new_value*/,
+                bool* /*value_changed*/) const override {
+      return false;
+    }
+
+    const char* Name() const override { return "KeepFilter"; }
+  };
+
+  std::shared_ptr<Cache> NewCache(int64_t capacity) {
+    if (capacity <= 0) {
+      return nullptr;
+    }
+    if (FLAGS_use_clock_cache) {
+      auto cache = NewClockCache((size_t)capacity, FLAGS_cache_numshardbits);
+      if (!cache) {
+        fprintf(stderr, "Clock cache not supported.");
+        exit(1);
+      }
+      return cache;
+    } else {
+      return NewLRUCache((size_t)capacity, FLAGS_cache_numshardbits,
+                         false /*strict_capacity_limit*/,
+                         FLAGS_cache_high_pri_pool_ratio);
+    }
+  }
+
+ public:
+  Benchmark()
+      : cache_(NewCache(FLAGS_cache_size)),
+        compressed_cache_(NewCache(FLAGS_compressed_cache_size)),
+        filter_policy_(FLAGS_bloom_bits >= 0
+                           ? NewBloomFilterPolicy(FLAGS_bloom_bits,
+                                                  FLAGS_use_block_based_filter)
+                           : nullptr),
+        prefix_extractor_(NewFixedPrefixTransform(FLAGS_prefix_size)),
+        num_(FLAGS_num),
+        value_size_(FLAGS_value_size),
+        key_size_(FLAGS_key_size),
+        prefix_size_(FLAGS_prefix_size),
+        keys_per_prefix_(FLAGS_keys_per_prefix),
+        entries_per_batch_(1),
+        reads_(FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads),
+        read_random_exp_range_(0.0),
+        writes_(FLAGS_writes < 0 ? FLAGS_num : FLAGS_writes),
+        readwrites_(
+            (FLAGS_writes < 0 && FLAGS_reads < 0)
+                ? FLAGS_num
+                : ((FLAGS_writes > FLAGS_reads) ? FLAGS_writes : FLAGS_reads)),
+        merge_keys_(FLAGS_merge_keys < 0 ? FLAGS_num : FLAGS_merge_keys),
+        report_file_operations_(FLAGS_report_file_operations),
+#ifndef ROCKSDB_LITE
+        use_blob_db_(FLAGS_use_blob_db)
+#else
+        use_blob_db_(false)
+#endif  // !ROCKSDB_LITE
+  {
+    // use simcache instead of cache
+    if (FLAGS_simcache_size >= 0) {
+      if (FLAGS_cache_numshardbits >= 1) {
+        cache_ =
+            NewSimCache(cache_, FLAGS_simcache_size, FLAGS_cache_numshardbits);
+      } else {
+        cache_ = NewSimCache(cache_, FLAGS_simcache_size, 0);
+      }
+    }
+
+    if (report_file_operations_) {
+      if (!FLAGS_hdfs.empty()) {
+        fprintf(stderr,
+                "--hdfs and --report_file_operations cannot be enabled "
+                "at the same time");
+        exit(1);
+      }
+      FLAGS_env = new ReportFileOpEnv(rocksdb::Env::Default());
+    }
+
+    if (FLAGS_prefix_size > FLAGS_key_size) {
+      fprintf(stderr, "prefix size is larger than key size");
+      exit(1);
+    }
+
+    std::vector<std::string> files;
+    FLAGS_env->GetChildren(FLAGS_db, &files);
+    for (size_t i = 0; i < files.size(); i++) {
+      if (Slice(files[i]).starts_with("heap-")) {
+        FLAGS_env->DeleteFile(FLAGS_db + "/" + files[i]);
+      }
+    }
+    if (!FLAGS_use_existing_db) {
+      Options options;
+      if (!FLAGS_wal_dir.empty()) {
+        options.wal_dir = FLAGS_wal_dir;
+      }
+#ifndef ROCKSDB_LITE
+      if (use_blob_db_) {
+        blob_db::DestroyBlobDB(FLAGS_db, options, blob_db::BlobDBOptions());
+      }
+#endif  // !ROCKSDB_LITE
+      DestroyDB(FLAGS_db, options);
+      if (!FLAGS_wal_dir.empty()) {
+        FLAGS_env->DeleteDir(FLAGS_wal_dir);
+      }
+
+      if (FLAGS_num_multi_db > 1) {
+        FLAGS_env->CreateDir(FLAGS_db);
+        if (!FLAGS_wal_dir.empty()) {
+          FLAGS_env->CreateDir(FLAGS_wal_dir);
+        }
+      }
+    }
+
+    listener_.reset(new ErrorHandlerListener());
+  }
+
+  ~Benchmark() {
+    db_.DeleteDBs();
+    delete prefix_extractor_;
+    if (cache_.get() != nullptr) {
+      // this will leak, but we're shutting down so nobody cares
+      cache_->DisownData();
+    }
+  }
+
+  Slice AllocateKey(std::unique_ptr<const char[]>* key_guard) {
+    char* data = new char[key_size_];
+    const char* const_data = data;
+    key_guard->reset(const_data);
+    return Slice(key_guard->get(), key_size_);
+  }
+
+  // Generate key according to the given specification and random number.
+  // The resulting key will have the following format (if keys_per_prefix_
+  // is positive), extra trailing bytes are either cut off or padded with '0'.
+  // The prefix value is derived from key value.
+  //   ----------------------------
+  //   | prefix 00000 | key 00000 |
+  //   ----------------------------
+  // If keys_per_prefix_ is 0, the key is simply a binary representation of
+  // random number followed by trailing '0's
+  //   ----------------------------
+  //   |        key 00000         |
+  //   ----------------------------
+  void GenerateKeyFromInt(uint64_t v, int64_t num_keys, Slice* key) {
+    if (!keys_.empty()) {
+      assert(FLAGS_use_existing_keys);
+      assert(keys_.size() == static_cast<size_t>(num_keys));
+      assert(v < static_cast<uint64_t>(num_keys));
+      *key = keys_[v];
+      return;
+    }
+    char* start = const_cast<char*>(key->data());
+    char* pos = start;
+    if (keys_per_prefix_ > 0) {
+      int64_t num_prefix = num_keys / keys_per_prefix_;
+      int64_t prefix = v % num_prefix;
+      int bytes_to_fill = std::min(prefix_size_, 8);
+      if (port::kLittleEndian) {
+        for (int i = 0; i < bytes_to_fill; ++i) {
+          pos[i] = (prefix >> ((bytes_to_fill - i - 1) << 3)) & 0xFF;
+        }
+      } else {
+        memcpy(pos, static_cast<void*>(&prefix), bytes_to_fill);
+      }
+      if (prefix_size_ > 8) {
+        // fill the rest with 0s
+        memset(pos + 8, '0', prefix_size_ - 8);
+      }
+      pos += prefix_size_;
+    }
+
+    int bytes_to_fill = std::min(key_size_ - static_cast<int>(pos - start), 8);
+    if (port::kLittleEndian) {
+      for (int i = 0; i < bytes_to_fill; ++i) {
+        pos[i] = (v >> ((bytes_to_fill - i - 1) << 3)) & 0xFF;
+      }
+    } else {
+      memcpy(pos, static_cast<void*>(&v), bytes_to_fill);
+    }
+    pos += bytes_to_fill;
+    if (key_size_ > pos - start) {
+      memset(pos, '0', key_size_ - (pos - start));
+    }
+  }
+
+  std::string GetPathForMultiple(std::string base_name, size_t id) {
+    if (!base_name.empty()) {
+#ifndef OS_WIN
+      if (base_name.back() != '/') {
+        base_name += '/';
+      }
+#else
+      if (base_name.back() != '\\') {
+        base_name += '\\';
+      }
+#endif
+    }
+    return base_name + ToString(id);
+  }
+
+void VerifyDBFromDB(std::string& truth_db_name) {
+  DBWithColumnFamilies truth_db;
+  auto s = DB::OpenForReadOnly(open_options_, truth_db_name, &truth_db.db);
+  if (!s.ok()) {
+    fprintf(stderr, "open error: %s\n", s.ToString().c_str());
+    exit(1);
+  }
+  ReadOptions ro;
+  ro.total_order_seek = true;
+  std::unique_ptr<Iterator> truth_iter(truth_db.db->NewIterator(ro));
+  std::unique_ptr<Iterator> db_iter(db_.db->NewIterator(ro));
+  // Verify that all the key/values in truth_db are retrivable in db with ::Get
+  fprintf(stderr, "Verifying db >= truth_db with ::Get...\n");
+  for (truth_iter->SeekToFirst(); truth_iter->Valid(); truth_iter->Next()) {
+      std::string value;
+      s = db_.db->Get(ro, truth_iter->key(), &value);
+      assert(s.ok());
+      // TODO(myabandeh): provide debugging hints
+      assert(Slice(value) == truth_iter->value());
+  }
+  // Verify that the db iterator does not give any extra key/value
+  fprintf(stderr, "Verifying db == truth_db...\n");
+  for (db_iter->SeekToFirst(), truth_iter->SeekToFirst(); db_iter->Valid(); db_iter->Next(), truth_iter->Next()) {
+    assert(truth_iter->Valid());
+    assert(truth_iter->value() == db_iter->value());
+  }
+  // No more key should be left unchecked in truth_db
+  assert(!truth_iter->Valid());
+  fprintf(stderr, "...Verified\n");
+}
+
+  void Run() {
+    if (!SanityCheck()) {
+      exit(1);
+    }
+    Open(&open_options_);
+    PrintHeader();
+    std::stringstream benchmark_stream(FLAGS_benchmarks);
+    std::string name;
+    std::unique_ptr<ExpiredTimeFilter> filter;
+    while (std::getline(benchmark_stream, name, ',')) {
+      // Sanitize parameters
+      num_ = FLAGS_num;
+      reads_ = (FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads);
+      writes_ = (FLAGS_writes < 0 ? FLAGS_num : FLAGS_writes);
+      deletes_ = (FLAGS_deletes < 0 ? FLAGS_num : FLAGS_deletes);
+      value_size_ = FLAGS_value_size;
+      key_size_ = FLAGS_key_size;
+      entries_per_batch_ = FLAGS_batch_size;
+      writes_before_delete_range_ = FLAGS_writes_before_delete_range;
+      writes_per_range_tombstone_ = FLAGS_writes_per_range_tombstone;
+      range_tombstone_width_ = FLAGS_range_tombstone_width;
+      max_num_range_tombstones_ = FLAGS_max_num_range_tombstones;
+      write_options_ = WriteOptions();
+      read_random_exp_range_ = FLAGS_read_random_exp_range;
+      if (FLAGS_sync) {
+        write_options_.sync = true;
+      }
+      write_options_.disableWAL = FLAGS_disable_wal;
+
+      void (Benchmark::*method)(ThreadState*) = nullptr;
+      void (Benchmark::*post_process_method)() = nullptr;
+
+      bool fresh_db = false;
+      int num_threads = FLAGS_threads;
+
+      int num_repeat = 1;
+      int num_warmup = 0;
+      if (!name.empty() && *name.rbegin() == ']') {
+        auto it = name.find('[');
+        if (it == std::string::npos) {
+          fprintf(stderr, "unknown benchmark arguments '%s'\n", name.c_str());
+          exit(1);
+        }
+        std::string args = name.substr(it + 1);
+        args.resize(args.size() - 1);
+        name.resize(it);
+
+        std::string bench_arg;
+        std::stringstream args_stream(args);
+        while (std::getline(args_stream, bench_arg, '-')) {
+          if (bench_arg.empty()) {
+            continue;
+          }
+          if (bench_arg[0] == 'X') {
+            // Repeat the benchmark n times
+            std::string num_str = bench_arg.substr(1);
+            num_repeat = std::stoi(num_str);
+          } else if (bench_arg[0] == 'W') {
+            // Warm up the benchmark for n times
+            std::string num_str = bench_arg.substr(1);
+            num_warmup = std::stoi(num_str);
+          }
+        }
+      }
+
+      // Both fillseqdeterministic and filluniquerandomdeterministic
+      // fill the levels except the max level with UNIQUE_RANDOM
+      // and fill the max level with fillseq and filluniquerandom, respectively
+      if (name == "fillseqdeterministic" ||
+          name == "filluniquerandomdeterministic") {
+        if (!FLAGS_disable_auto_compactions) {
+          fprintf(stderr,
+                  "Please disable_auto_compactions in FillDeterministic "
+                  "benchmark\n");
+          exit(1);
+        }
+        if (num_threads > 1) {
+          fprintf(stderr,
+                  "filldeterministic multithreaded not supported"
+                  ", use 1 thread\n");
+          num_threads = 1;
+        }
+        fresh_db = true;
+        if (name == "fillseqdeterministic") {
+          method = &Benchmark::WriteSeqDeterministic;
+        } else {
+          method = &Benchmark::WriteUniqueRandomDeterministic;
+        }
+      } else if (name == "fillseq") {
+        fresh_db = true;
+        method = &Benchmark::WriteSeq;
+      } else if (name == "fillbatch") {
+        fresh_db = true;
+        entries_per_batch_ = 1000;
+        method = &Benchmark::WriteSeq;
+      } else if (name == "fillrandom") {
+        fresh_db = true;
+        method = &Benchmark::WriteRandom;
+      } else if (name == "filluniquerandom") {
+        fresh_db = true;
+        if (num_threads > 1) {
+          fprintf(stderr,
+                  "filluniquerandom multithreaded not supported"
+                  ", use 1 thread");
+          num_threads = 1;
+        }
+        method = &Benchmark::WriteUniqueRandom;
+      } else if (name == "overwrite") {
+        method = &Benchmark::WriteRandom;
+      } else if (name == "fillsync") {
+        fresh_db = true;
+        num_ /= 1000;
+        write_options_.sync = true;
+        method = &Benchmark::WriteRandom;
+      } else if (name == "fill100K") {
+        fresh_db = true;
+        num_ /= 1000;
+        value_size_ = 100 * 1000;
+        method = &Benchmark::WriteRandom;
+      } else if (name == "readseq") {
+        method = &Benchmark::ReadSequential;
+      } else if (name == "readtocache") {
+        method = &Benchmark::ReadSequential;
+        num_threads = 1;
+        reads_ = num_;
+      } else if (name == "readreverse") {
+        method = &Benchmark::ReadReverse;
+      } else if (name == "readrandom") {
+        method = &Benchmark::ReadRandom;
+      } else if (name == "readrandomfast") {
+        method = &Benchmark::ReadRandomFast;
+      } else if (name == "multireadrandom") {
+        fprintf(stderr, "entries_per_batch = %" PRIi64 "\n",
+                entries_per_batch_);
+        method = &Benchmark::MultiReadRandom;
+      } else if (name == "mixgraph") {
+        method = &Benchmark::MixGraph;
+      } else if (name == "readmissing") {
+        ++key_size_;
+        method = &Benchmark::ReadRandom;
+      } else if (name == "newiterator") {
+        method = &Benchmark::IteratorCreation;
+      } else if (name == "newiteratorwhilewriting") {
+        num_threads++;  // Add extra thread for writing
+        method = &Benchmark::IteratorCreationWhileWriting;
+      } else if (name == "seekrandom") {
+        method = &Benchmark::SeekRandom;
+      } else if (name == "seekrandomwhilewriting") {
+        num_threads++;  // Add extra thread for writing
+        method = &Benchmark::SeekRandomWhileWriting;
+      } else if (name == "seekrandomwhilemerging") {
+        num_threads++;  // Add extra thread for merging
+        method = &Benchmark::SeekRandomWhileMerging;
+      } else if (name == "readrandomsmall") {
+        reads_ /= 1000;
+        method = &Benchmark::ReadRandom;
+      } else if (name == "deleteseq") {
+        method = &Benchmark::DeleteSeq;
+      } else if (name == "deleterandom") {
+        method = &Benchmark::DeleteRandom;
+      } else if (name == "readwhilewriting") {
+        num_threads++;  // Add extra thread for writing
+        method = &Benchmark::ReadWhileWriting;
+      } else if (name == "readwhilemerging") {
+        num_threads++;  // Add extra thread for writing
+        method = &Benchmark::ReadWhileMerging;
+      } else if (name == "readwhilescanning") {
+        num_threads++;  // Add extra thread for scaning
+        method = &Benchmark::ReadWhileScanning;
+      } else if (name == "readrandomwriterandom") {
+        method = &Benchmark::ReadRandomWriteRandom;
+      } else if (name == "readrandommergerandom") {
+        if (FLAGS_merge_operator.empty()) {
+          fprintf(stdout, "%-12s : skipped (--merge_operator is unknown)\n",
+                  name.c_str());
+          exit(1);
+        }
+        method = &Benchmark::ReadRandomMergeRandom;
+      } else if (name == "updaterandom") {
+        method = &Benchmark::UpdateRandom;
+      } else if (name == "xorupdaterandom") {
+        method = &Benchmark::XORUpdateRandom;
+      } else if (name == "appendrandom") {
+        method = &Benchmark::AppendRandom;
+      } else if (name == "mergerandom") {
+        if (FLAGS_merge_operator.empty()) {
+          fprintf(stdout, "%-12s : skipped (--merge_operator is unknown)\n",
+                  name.c_str());
+          exit(1);
+        }
+        method = &Benchmark::MergeRandom;
+      } else if (name == "randomwithverify") {
+        method = &Benchmark::RandomWithVerify;
+      } else if (name == "fillseekseq") {
+        method = &Benchmark::WriteSeqSeekSeq;
+      } else if (name == "compact") {
+        method = &Benchmark::Compact;
+      } else if (name == "compactall") {
+        CompactAll();
+      } else if (name == "crc32c") {
+        method = &Benchmark::Crc32c;
+      } else if (name == "xxhash") {
+        method = &Benchmark::xxHash;
+      } else if (name == "acquireload") {
+        method = &Benchmark::AcquireLoad;
+      } else if (name == "compress") {
+        method = &Benchmark::Compress;
+      } else if (name == "uncompress") {
+        method = &Benchmark::Uncompress;
+#ifndef ROCKSDB_LITE
+      } else if (name == "randomtransaction") {
+        method = &Benchmark::RandomTransaction;
+        post_process_method = &Benchmark::RandomTransactionVerify;
+#endif  // ROCKSDB_LITE
+      } else if (name == "randomreplacekeys") {
+        fresh_db = true;
+        method = &Benchmark::RandomReplaceKeys;
+      } else if (name == "timeseries") {
+        timestamp_emulator_.reset(new TimestampEmulator());
+        if (FLAGS_expire_style == "compaction_filter") {
+          filter.reset(new ExpiredTimeFilter(timestamp_emulator_));
+          fprintf(stdout, "Compaction filter is used to remove expired data");
+          open_options_.compaction_filter = filter.get();
+        }
+        fresh_db = true;
+        method = &Benchmark::TimeSeries;
+      } else if (name == "stats") {
+        PrintStats("rocksdb.stats");
+      } else if (name == "resetstats") {
+        ResetStats();
+      } else if (name == "verify") {
+        VerifyDBFromDB(FLAGS_truth_db);
+      } else if (name == "levelstats") {
+        PrintStats("rocksdb.levelstats");
+      } else if (name == "sstables") {
+        PrintStats("rocksdb.sstables");
+      } else if (name == "replay") {
+        if (num_threads > 1) {
+          fprintf(stderr, "Multi-threaded replay is not yet supported\n");
+          exit(1);
+        }
+        if (FLAGS_trace_file == "") {
+          fprintf(stderr, "Please set --trace_file to be replayed from\n");
+          exit(1);
+        }
+        method = &Benchmark::Replay;
+      } else if (!name.empty()) {  // No error message for empty name
+        fprintf(stderr, "unknown benchmark '%s'\n", name.c_str());
+        exit(1);
+      }
+
+      if (fresh_db) {
+        if (FLAGS_use_existing_db) {
+          fprintf(stdout, "%-12s : skipped (--use_existing_db is true)\n",
+                  name.c_str());
+          method = nullptr;
+        } else {
+          if (db_.db != nullptr) {
+            db_.DeleteDBs();
+            DestroyDB(FLAGS_db, open_options_);
+          }
+          Options options = open_options_;
+          for (size_t i = 0; i < multi_dbs_.size(); i++) {
+            delete multi_dbs_[i].db;
+            if (!open_options_.wal_dir.empty()) {
+              options.wal_dir = GetPathForMultiple(open_options_.wal_dir, i);
+            }
+            DestroyDB(GetPathForMultiple(FLAGS_db, i), options);
+          }
+          multi_dbs_.clear();
+        }
+        Open(&open_options_);  // use open_options for the last accessed
+      }
+
+      if (method != nullptr) {
+        fprintf(stdout, "DB path: [%s]\n", FLAGS_db.c_str());
+
+#ifndef ROCKSDB_LITE
+        // A trace_file option can be provided both for trace and replay
+        // operations. But db_bench does not support tracing and replaying at
+        // the same time, for now. So, start tracing only when it is not a
+        // replay.
+        if (FLAGS_trace_file != "" && name != "replay") {
+          std::unique_ptr<TraceWriter> trace_writer;
+          Status s = NewFileTraceWriter(FLAGS_env, EnvOptions(),
+                                        FLAGS_trace_file, &trace_writer);
+          if (!s.ok()) {
+            fprintf(stderr, "Encountered an error starting a trace, %s\n",
+                    s.ToString().c_str());
+            exit(1);
+          }
+          s = db_.db->StartTrace(trace_options_, std::move(trace_writer));
+          if (!s.ok()) {
+            fprintf(stderr, "Encountered an error starting a trace, %s\n",
+                    s.ToString().c_str());
+            exit(1);
+          }
+          fprintf(stdout, "Tracing the workload to: [%s]\n",
+                  FLAGS_trace_file.c_str());
+        }
+#endif  // ROCKSDB_LITE
+
+        if (num_warmup > 0) {
+          printf("Warming up benchmark by running %d times\n", num_warmup);
+        }
+
+        for (int i = 0; i < num_warmup; i++) {
+          RunBenchmark(num_threads, name, method);
+        }
+
+        if (num_repeat > 1) {
+          printf("Running benchmark for %d times\n", num_repeat);
+        }
+
+        CombinedStats combined_stats;
+        for (int i = 0; i < num_repeat; i++) {
+          Stats stats = RunBenchmark(num_threads, name, method);
+          combined_stats.AddStats(stats);
+        }
+        if (num_repeat > 1) {
+          combined_stats.Report(name);
+        }
+      }
+      if (post_process_method != nullptr) {
+        (this->*post_process_method)();
+      }
+    }
+
+#ifndef ROCKSDB_LITE
+    if (name != "replay" && FLAGS_trace_file != "") {
+      Status s = db_.db->EndTrace();
+      if (!s.ok()) {
+        fprintf(stderr, "Encountered an error ending the trace, %s\n",
+                s.ToString().c_str());
+      }
+    }
+#endif  // ROCKSDB_LITE
+
+    if (FLAGS_statistics) {
+      fprintf(stdout, "STATISTICS:\n%s\n", dbstats->ToString().c_str());
+    }
+    if (FLAGS_simcache_size >= 0) {
+      fprintf(stdout, "SIMULATOR CACHE STATISTICS:\n%s\n",
+              static_cast_with_check<SimCache, Cache>(cache_.get())
+                  ->ToString()
+                  .c_str());
+    }
+  }
+
+ private:
+  std::shared_ptr<TimestampEmulator> timestamp_emulator_;
+
+  struct ThreadArg {
+    Benchmark* bm;
+    SharedState* shared;
+    ThreadState* thread;
+    void (Benchmark::*method)(ThreadState*);
+  };
+
+  static void ThreadBody(void* v) {
+    ThreadArg* arg = reinterpret_cast<ThreadArg*>(v);
+    SharedState* shared = arg->shared;
+    ThreadState* thread = arg->thread;
+    {
+      MutexLock l(&shared->mu);
+      shared->num_initialized++;
+      if (shared->num_initialized >= shared->total) {
+        shared->cv.SignalAll();
+      }
+      while (!shared->start) {
+        shared->cv.Wait();
+      }
+    }
+
+    SetPerfLevel(static_cast<PerfLevel> (shared->perf_level));
+    perf_context.EnablePerLevelPerfContext();
+    thread->stats.Start(thread->tid);
+    (arg->bm->*(arg->method))(thread);
+    thread->stats.Stop();
+
+    {
+      MutexLock l(&shared->mu);
+      shared->num_done++;
+      if (shared->num_done >= shared->total) {
+        shared->cv.SignalAll();
+      }
+    }
+  }
+
+  Stats RunBenchmark(int n, Slice name,
+                     void (Benchmark::*method)(ThreadState*)) {
+    SharedState shared;
+    shared.total = n;
+    shared.num_initialized = 0;
+    shared.num_done = 0;
+    shared.start = false;
+    if (FLAGS_benchmark_write_rate_limit > 0) {
+      shared.write_rate_limiter.reset(
+          NewGenericRateLimiter(FLAGS_benchmark_write_rate_limit));
+    }
+    if (FLAGS_benchmark_read_rate_limit > 0) {
+      shared.read_rate_limiter.reset(NewGenericRateLimiter(
+          FLAGS_benchmark_read_rate_limit, 100000 /* refill_period_us */,
+          10 /* fairness */, RateLimiter::Mode::kReadsOnly));
+    }
+
+    std::unique_ptr<ReporterAgent> reporter_agent;
+    if (FLAGS_report_interval_seconds > 0) {
+      reporter_agent.reset(new ReporterAgent(FLAGS_env, FLAGS_report_file,
+                                             FLAGS_report_interval_seconds));
+    }
+
+    ThreadArg* arg = new ThreadArg[n];
+
+    for (int i = 0; i < n; i++) {
+#ifdef NUMA
+      if (FLAGS_enable_numa) {
+        // Performs a local allocation of memory to threads in numa node.
+        int n_nodes = numa_num_task_nodes();  // Number of nodes in NUMA.
+        numa_exit_on_error = 1;
+        int numa_node = i % n_nodes;
+        bitmask* nodes = numa_allocate_nodemask();
+        numa_bitmask_clearall(nodes);
+        numa_bitmask_setbit(nodes, numa_node);
+        // numa_bind() call binds the process to the node and these
+        // properties are passed on to the thread that is created in
+        // StartThread method called later in the loop.
+        numa_bind(nodes);
+        numa_set_strict(1);
+        numa_free_nodemask(nodes);
+      }
+#endif
+      arg[i].bm = this;
+      arg[i].method = method;
+      arg[i].shared = &shared;
+      arg[i].thread = new ThreadState(i);
+      arg[i].thread->stats.SetReporterAgent(reporter_agent.get());
+      arg[i].thread->shared = &shared;
+      FLAGS_env->StartThread(ThreadBody, &arg[i]);
+    }
+
+    shared.mu.Lock();
+    while (shared.num_initialized < n) {
+      shared.cv.Wait();
+    }
+
+    shared.start = true;
+    shared.cv.SignalAll();
+    while (shared.num_done < n) {
+      shared.cv.Wait();
+    }
+    shared.mu.Unlock();
+
+    // Stats for some threads can be excluded.
+    Stats merge_stats;
+    for (int i = 0; i < n; i++) {
+      merge_stats.Merge(arg[i].thread->stats);
+    }
+    merge_stats.Report(name);
+
+    for (int i = 0; i < n; i++) {
+      delete arg[i].thread;
+    }
+    delete[] arg;
+
+    return merge_stats;
+  }
+
+  void Crc32c(ThreadState* thread) {
+    // Checksum about 500MB of data total
+    const int size = FLAGS_block_size; // use --block_size option for db_bench
+    std::string labels = "(" + ToString(FLAGS_block_size) + " per op)";
+    const char* label = labels.c_str();
+
+    std::string data(size, 'x');
+    int64_t bytes = 0;
+    uint32_t crc = 0;
+    while (bytes < 500 * 1048576) {
+      crc = crc32c::Value(data.data(), size);
+      thread->stats.FinishedOps(nullptr, nullptr, 1, kCrc);
+      bytes += size;
+    }
+    // Print so result is not dead
+    fprintf(stderr, "... crc=0x%x\r", static_cast<unsigned int>(crc));
+
+    thread->stats.AddBytes(bytes);
+    thread->stats.AddMessage(label);
+  }
+
+  void xxHash(ThreadState* thread) {
+    // Checksum about 500MB of data total
+    const int size = 4096;
+    const char* label = "(4K per op)";
+    std::string data(size, 'x');
+    int64_t bytes = 0;
+    unsigned int xxh32 = 0;
+    while (bytes < 500 * 1048576) {
+      xxh32 = XXH32(data.data(), size, 0);
+      thread->stats.FinishedOps(nullptr, nullptr, 1, kHash);
+      bytes += size;
+    }
+    // Print so result is not dead
+    fprintf(stderr, "... xxh32=0x%x\r", static_cast<unsigned int>(xxh32));
+
+    thread->stats.AddBytes(bytes);
+    thread->stats.AddMessage(label);
+  }
+
+  void AcquireLoad(ThreadState* thread) {
+    int dummy;
+    std::atomic<void*> ap(&dummy);
+    int count = 0;
+    void *ptr = nullptr;
+    thread->stats.AddMessage("(each op is 1000 loads)");
+    while (count < 100000) {
+      for (int i = 0; i < 1000; i++) {
+        ptr = ap.load(std::memory_order_acquire);
+      }
+      count++;
+      thread->stats.FinishedOps(nullptr, nullptr, 1, kOthers);
+    }
+    if (ptr == nullptr) exit(1);  // Disable unused variable warning.
+  }
+
+  void Compress(ThreadState *thread) {
+    RandomGenerator gen;
+    Slice input = gen.Generate(FLAGS_block_size);
+    int64_t bytes = 0;
+    int64_t produced = 0;
+    bool ok = true;
+    std::string compressed;
+    CompressionOptions opts;
+    CompressionContext context(FLAGS_compression_type_e);
+    CompressionInfo info(opts, context, CompressionDict::GetEmptyDict(),
+                         FLAGS_compression_type_e,
+                         FLAGS_sample_for_compression);
+    // Compress 1G
+    while (ok && bytes < int64_t(1) << 30) {
+      compressed.clear();
+      ok = CompressSlice(info, input, &compressed);
+      produced += compressed.size();
+      bytes += input.size();
+      thread->stats.FinishedOps(nullptr, nullptr, 1, kCompress);
+    }
+
+    if (!ok) {
+      thread->stats.AddMessage("(compression failure)");
+    } else {
+      char buf[340];
+      snprintf(buf, sizeof(buf), "(output: %.1f%%)",
+               (produced * 100.0) / bytes);
+      thread->stats.AddMessage(buf);
+      thread->stats.AddBytes(bytes);
+    }
+  }
+
+  void Uncompress(ThreadState *thread) {
+    RandomGenerator gen;
+    Slice input = gen.Generate(FLAGS_block_size);
+    std::string compressed;
+
+    CompressionContext compression_ctx(FLAGS_compression_type_e);
+    CompressionOptions compression_opts;
+    CompressionInfo compression_info(
+        compression_opts, compression_ctx, CompressionDict::GetEmptyDict(),
+        FLAGS_compression_type_e, FLAGS_sample_for_compression);
+    UncompressionContext uncompression_ctx(FLAGS_compression_type_e);
+    UncompressionInfo uncompression_info(uncompression_ctx,
+                                         UncompressionDict::GetEmptyDict(),
+                                         FLAGS_compression_type_e);
+
+    bool ok = CompressSlice(compression_info, input, &compressed);
+    int64_t bytes = 0;
+    int decompress_size;
+    while (ok && bytes < 1024 * 1048576) {
+      CacheAllocationPtr uncompressed;
+      switch (FLAGS_compression_type_e) {
+        case rocksdb::kSnappyCompression: {
+          // get size and allocate here to make comparison fair
+          size_t ulength = 0;
+          if (!Snappy_GetUncompressedLength(compressed.data(),
+                                            compressed.size(), &ulength)) {
+            ok = false;
+            break;
+          }
+          uncompressed = AllocateBlock(ulength, nullptr);
+          ok = Snappy_Uncompress(compressed.data(), compressed.size(),
+                                 uncompressed.get());
+          break;
+        }
+      case rocksdb::kZlibCompression:
+        uncompressed = Zlib_Uncompress(uncompression_info, compressed.data(),
+                                       compressed.size(), &decompress_size, 2);
+        ok = uncompressed.get() != nullptr;
+        break;
+      case rocksdb::kBZip2Compression:
+        uncompressed = BZip2_Uncompress(compressed.data(), compressed.size(),
+                                        &decompress_size, 2);
+        ok = uncompressed.get() != nullptr;
+        break;
+      case rocksdb::kLZ4Compression:
+        uncompressed = LZ4_Uncompress(uncompression_info, compressed.data(),
+                                      compressed.size(), &decompress_size, 2);
+        ok = uncompressed.get() != nullptr;
+        break;
+      case rocksdb::kLZ4HCCompression:
+        uncompressed = LZ4_Uncompress(uncompression_info, compressed.data(),
+                                      compressed.size(), &decompress_size, 2);
+        ok = uncompressed.get() != nullptr;
+        break;
+      case rocksdb::kXpressCompression:
+        uncompressed.reset(XPRESS_Uncompress(
+            compressed.data(), compressed.size(), &decompress_size));
+        ok = uncompressed.get() != nullptr;
+        break;
+      case rocksdb::kZSTD:
+        uncompressed = ZSTD_Uncompress(uncompression_info, compressed.data(),
+                                       compressed.size(), &decompress_size);
+        ok = uncompressed.get() != nullptr;
+        break;
+      default:
+        ok = false;
+      }
+      bytes += input.size();
+      thread->stats.FinishedOps(nullptr, nullptr, 1, kUncompress);
+    }
+
+    if (!ok) {
+      thread->stats.AddMessage("(compression failure)");
+    } else {
+      thread->stats.AddBytes(bytes);
+    }
+  }
+
+  // Returns true if the options is initialized from the specified
+  // options file.
+  bool InitializeOptionsFromFile(Options* opts) {
+#ifndef ROCKSDB_LITE
+    printf("Initializing RocksDB Options from the specified file\n");
+    DBOptions db_opts;
+    std::vector<ColumnFamilyDescriptor> cf_descs;
+    if (FLAGS_options_file != "") {
+      auto s = LoadOptionsFromFile(FLAGS_options_file, Env::Default(), &db_opts,
+                                   &cf_descs);
+      if (s.ok()) {
+        *opts = Options(db_opts, cf_descs[0].options);
+        return true;
+      }
+      fprintf(stderr, "Unable to load options file %s --- %s\n",
+              FLAGS_options_file.c_str(), s.ToString().c_str());
+      exit(1);
+    }
+#else
+    (void)opts;
+#endif
+    return false;
+  }
+
+  void InitializeOptionsFromFlags(Options* opts) {
+    printf("Initializing RocksDB Options from command-line flags\n");
+    Options& options = *opts;
+
+    assert(db_.db == nullptr);
+
+    options.max_open_files = FLAGS_open_files;
+    if (FLAGS_cost_write_buffer_to_cache || FLAGS_db_write_buffer_size != 0) {
+      options.write_buffer_manager.reset(
+          new WriteBufferManager(FLAGS_db_write_buffer_size, cache_));
+    }
+    options.write_buffer_size = FLAGS_write_buffer_size;
+    options.max_write_buffer_number = FLAGS_max_write_buffer_number;
+    options.min_write_buffer_number_to_merge =
+      FLAGS_min_write_buffer_number_to_merge;
+    options.max_write_buffer_number_to_maintain =
+        FLAGS_max_write_buffer_number_to_maintain;
+    options.max_background_jobs = FLAGS_max_background_jobs;
+    options.max_background_compactions = FLAGS_max_background_compactions;
+    options.max_subcompactions = static_cast<uint32_t>(FLAGS_subcompactions);
+    options.max_background_flushes = FLAGS_max_background_flushes;
+    options.compaction_style = FLAGS_compaction_style_e;
+    options.compaction_pri = FLAGS_compaction_pri_e;
+    options.allow_mmap_reads = FLAGS_mmap_read;
+    options.allow_mmap_writes = FLAGS_mmap_write;
+    options.use_direct_reads = FLAGS_use_direct_reads;
+    options.use_direct_io_for_flush_and_compaction =
+        FLAGS_use_direct_io_for_flush_and_compaction;
+#ifndef ROCKSDB_LITE
+    options.ttl = FLAGS_fifo_compaction_ttl;
+    options.compaction_options_fifo = CompactionOptionsFIFO(
+        FLAGS_fifo_compaction_max_table_files_size_mb * 1024 * 1024,
+        FLAGS_fifo_compaction_allow_compaction);
+#endif  // ROCKSDB_LITE
+    if (FLAGS_prefix_size != 0) {
+      options.prefix_extractor.reset(
+          NewFixedPrefixTransform(FLAGS_prefix_size));
+    }
+    if (FLAGS_use_uint64_comparator) {
+      options.comparator = test::Uint64Comparator();
+      if (FLAGS_key_size != 8) {
+        fprintf(stderr, "Using Uint64 comparator but key size is not 8.\n");
+        exit(1);
+      }
+    }
+    if (FLAGS_use_stderr_info_logger) {
+      options.info_log.reset(new StderrLogger());
+    }
+    options.memtable_huge_page_size = FLAGS_memtable_use_huge_page ? 2048 : 0;
+    options.memtable_prefix_bloom_size_ratio = FLAGS_memtable_bloom_size_ratio;
+    options.memtable_whole_key_filtering = FLAGS_memtable_whole_key_filtering;
+    if (FLAGS_memtable_insert_with_hint_prefix_size > 0) {
+      options.memtable_insert_with_hint_prefix_extractor.reset(
+          NewCappedPrefixTransform(
+              FLAGS_memtable_insert_with_hint_prefix_size));
+    }
+    options.bloom_locality = FLAGS_bloom_locality;
+    options.max_file_opening_threads = FLAGS_file_opening_threads;
+    options.new_table_reader_for_compaction_inputs =
+        FLAGS_new_table_reader_for_compaction_inputs;
+    options.compaction_readahead_size = FLAGS_compaction_readahead_size;
+    options.random_access_max_buffer_size = FLAGS_random_access_max_buffer_size;
+    options.writable_file_max_buffer_size = FLAGS_writable_file_max_buffer_size;
+    options.use_fsync = FLAGS_use_fsync;
+    options.num_levels = FLAGS_num_levels;
+    options.target_file_size_base = FLAGS_target_file_size_base;
+    options.target_file_size_multiplier = FLAGS_target_file_size_multiplier;
+    options.max_bytes_for_level_base = FLAGS_max_bytes_for_level_base;
+    options.level_compaction_dynamic_level_bytes =
+        FLAGS_level_compaction_dynamic_level_bytes;
+    options.max_bytes_for_level_multiplier =
+        FLAGS_max_bytes_for_level_multiplier;
+    if ((FLAGS_prefix_size == 0) && (FLAGS_rep_factory == kPrefixHash ||
+                                     FLAGS_rep_factory == kHashLinkedList)) {
+      fprintf(stderr, "prefix_size should be non-zero if PrefixHash or "
+                      "HashLinkedList memtablerep is used\n");
+      exit(1);
+    }
+    switch (FLAGS_rep_factory) {
+      case kSkipList:
+        options.memtable_factory.reset(new SkipListFactory(
+            FLAGS_skip_list_lookahead));
+        break;
+#ifndef ROCKSDB_LITE
+      case kPrefixHash:
+        options.memtable_factory.reset(
+            NewHashSkipListRepFactory(FLAGS_hash_bucket_count));
+        break;
+      case kHashLinkedList:
+        options.memtable_factory.reset(NewHashLinkListRepFactory(
+            FLAGS_hash_bucket_count));
+        break;
+      case kVectorRep:
+        options.memtable_factory.reset(
+          new VectorRepFactory
+        );
+        break;
+#else
+      default:
+        fprintf(stderr, "Only skip list is supported in lite mode\n");
+        exit(1);
+#endif  // ROCKSDB_LITE
+    }
+    if (FLAGS_use_plain_table) {
+#ifndef ROCKSDB_LITE
+      if (FLAGS_rep_factory != kPrefixHash &&
+          FLAGS_rep_factory != kHashLinkedList) {
+        fprintf(stderr, "Waring: plain table is used with skipList\n");
+      }
+
+      int bloom_bits_per_key = FLAGS_bloom_bits;
+      if (bloom_bits_per_key < 0) {
+        bloom_bits_per_key = 0;
+      }
+
+      PlainTableOptions plain_table_options;
+      plain_table_options.user_key_len = FLAGS_key_size;
+      plain_table_options.bloom_bits_per_key = bloom_bits_per_key;
+      plain_table_options.hash_table_ratio = 0.75;
+      options.table_factory = std::shared_ptr<TableFactory>(
+          NewPlainTableFactory(plain_table_options));
+#else
+      fprintf(stderr, "Plain table is not supported in lite mode\n");
+      exit(1);
+#endif  // ROCKSDB_LITE
+    } else if (FLAGS_use_cuckoo_table) {
+#ifndef ROCKSDB_LITE
+      if (FLAGS_cuckoo_hash_ratio > 1 || FLAGS_cuckoo_hash_ratio < 0) {
+        fprintf(stderr, "Invalid cuckoo_hash_ratio\n");
+        exit(1);
+      }
+
+      if (!FLAGS_mmap_read) {
+        fprintf(stderr, "cuckoo table format requires mmap read to operate\n");
+        exit(1);
+      }
+
+      rocksdb::CuckooTableOptions table_options;
+      table_options.hash_table_ratio = FLAGS_cuckoo_hash_ratio;
+      table_options.identity_as_first_hash = FLAGS_identity_as_first_hash;
+      options.table_factory = std::shared_ptr<TableFactory>(
+          NewCuckooTableFactory(table_options));
+#else
+      fprintf(stderr, "Cuckoo table is not supported in lite mode\n");
+      exit(1);
+#endif  // ROCKSDB_LITE
+    } else {
+      BlockBasedTableOptions block_based_options;
+      if (FLAGS_use_hash_search) {
+        if (FLAGS_prefix_size == 0) {
+          fprintf(stderr,
+              "prefix_size not assigned when enable use_hash_search \n");
+          exit(1);
+        }
+        block_based_options.index_type = BlockBasedTableOptions::kHashSearch;
+      } else {
+        block_based_options.index_type = BlockBasedTableOptions::kBinarySearch;
+      }
+      if (FLAGS_partition_index_and_filters || FLAGS_partition_index) {
+        if (FLAGS_use_hash_search) {
+          fprintf(stderr,
+                  "use_hash_search is incompatible with "
+                  "partition index and is ignored");
+        }
+        block_based_options.index_type =
+            BlockBasedTableOptions::kTwoLevelIndexSearch;
+        block_based_options.metadata_block_size = FLAGS_metadata_block_size;
+        if (FLAGS_partition_index_and_filters) {
+          block_based_options.partition_filters = true;
+        }
+      }
+      if (cache_ == nullptr) {
+        block_based_options.no_block_cache = true;
+      }
+      block_based_options.cache_index_and_filter_blocks =
+          FLAGS_cache_index_and_filter_blocks;
+      block_based_options.pin_l0_filter_and_index_blocks_in_cache =
+          FLAGS_pin_l0_filter_and_index_blocks_in_cache;
+      block_based_options.pin_top_level_index_and_filter =
+          FLAGS_pin_top_level_index_and_filter;
+      if (FLAGS_cache_high_pri_pool_ratio > 1e-6) {  // > 0.0 + eps
+        block_based_options.cache_index_and_filter_blocks_with_high_priority =
+            true;
+      }
+      block_based_options.block_cache = cache_;
+      block_based_options.block_cache_compressed = compressed_cache_;
+      block_based_options.block_size = FLAGS_block_size;
+      block_based_options.block_restart_interval = FLAGS_block_restart_interval;
+      block_based_options.index_block_restart_interval =
+          FLAGS_index_block_restart_interval;
+      block_based_options.filter_policy = filter_policy_;
+      block_based_options.format_version =
+          static_cast<uint32_t>(FLAGS_format_version);
+      block_based_options.read_amp_bytes_per_bit = FLAGS_read_amp_bytes_per_bit;
+      block_based_options.enable_index_compression =
+          FLAGS_enable_index_compression;
+      block_based_options.block_align = FLAGS_block_align;
+      if (FLAGS_use_data_block_hash_index) {
+        block_based_options.data_block_index_type =
+            rocksdb::BlockBasedTableOptions::kDataBlockBinaryAndHash;
+      } else {
+        block_based_options.data_block_index_type =
+            rocksdb::BlockBasedTableOptions::kDataBlockBinarySearch;
+      }
+      block_based_options.data_block_hash_table_util_ratio =
+          FLAGS_data_block_hash_table_util_ratio;
+      if (FLAGS_read_cache_path != "") {
+#ifndef ROCKSDB_LITE
+        Status rc_status;
+
+        // Read cache need to be provided with a the Logger, we will put all
+        // reac cache logs in the read cache path in a file named rc_LOG
+        rc_status = FLAGS_env->CreateDirIfMissing(FLAGS_read_cache_path);
+        std::shared_ptr<Logger> read_cache_logger;
+        if (rc_status.ok()) {
+          rc_status = FLAGS_env->NewLogger(FLAGS_read_cache_path + "/rc_LOG",
+                                           &read_cache_logger);
+        }
+
+        if (rc_status.ok()) {
+          PersistentCacheConfig rc_cfg(FLAGS_env, FLAGS_read_cache_path,
+                                       FLAGS_read_cache_size,
+                                       read_cache_logger);
+
+          rc_cfg.enable_direct_reads = FLAGS_read_cache_direct_read;
+          rc_cfg.enable_direct_writes = FLAGS_read_cache_direct_write;
+          rc_cfg.writer_qdepth = 4;
+          rc_cfg.writer_dispatch_size = 4 * 1024;
+
+          auto pcache = std::make_shared<BlockCacheTier>(rc_cfg);
+          block_based_options.persistent_cache = pcache;
+          rc_status = pcache->Open();
+        }
+
+        if (!rc_status.ok()) {
+          fprintf(stderr, "Error initializing read cache, %s\n",
+                  rc_status.ToString().c_str());
+          exit(1);
+        }
+#else
+        fprintf(stderr, "Read cache is not supported in LITE\n");
+        exit(1);
+
+#endif
+      }
+      options.table_factory.reset(
+          NewBlockBasedTableFactory(block_based_options));
+    }
+    if (FLAGS_max_bytes_for_level_multiplier_additional_v.size() > 0) {
+      if (FLAGS_max_bytes_for_level_multiplier_additional_v.size() !=
+          (unsigned int)FLAGS_num_levels) {
+        fprintf(stderr, "Insufficient number of fanouts specified %d\n",
+                (int)FLAGS_max_bytes_for_level_multiplier_additional_v.size());
+        exit(1);
+      }
+      options.max_bytes_for_level_multiplier_additional =
+        FLAGS_max_bytes_for_level_multiplier_additional_v;
+    }
+    options.level0_stop_writes_trigger = FLAGS_level0_stop_writes_trigger;
+    options.level0_file_num_compaction_trigger =
+        FLAGS_level0_file_num_compaction_trigger;
+    options.level0_slowdown_writes_trigger =
+      FLAGS_level0_slowdown_writes_trigger;
+    options.compression = FLAGS_compression_type_e;
+    options.sample_for_compression = FLAGS_sample_for_compression;
+    options.WAL_ttl_seconds = FLAGS_wal_ttl_seconds;
+    options.WAL_size_limit_MB = FLAGS_wal_size_limit_MB;
+    options.max_total_wal_size = FLAGS_max_total_wal_size;
+
+    if (FLAGS_min_level_to_compress >= 0) {
+      assert(FLAGS_min_level_to_compress <= FLAGS_num_levels);
+      options.compression_per_level.resize(FLAGS_num_levels);
+      for (int i = 0; i < FLAGS_min_level_to_compress; i++) {
+        options.compression_per_level[i] = kNoCompression;
+      }
+      for (int i = FLAGS_min_level_to_compress;
+           i < FLAGS_num_levels; i++) {
+        options.compression_per_level[i] = FLAGS_compression_type_e;
+      }
+    }
+    options.soft_rate_limit = FLAGS_soft_rate_limit;
+    options.hard_rate_limit = FLAGS_hard_rate_limit;
+    options.soft_pending_compaction_bytes_limit =
+        FLAGS_soft_pending_compaction_bytes_limit;
+    options.hard_pending_compaction_bytes_limit =
+        FLAGS_hard_pending_compaction_bytes_limit;
+    options.delayed_write_rate = FLAGS_delayed_write_rate;
+    options.allow_concurrent_memtable_write =
+        FLAGS_allow_concurrent_memtable_write;
+    options.inplace_update_support = FLAGS_inplace_update_support;
+    options.inplace_update_num_locks = FLAGS_inplace_update_num_locks;
+    options.enable_write_thread_adaptive_yield =
+        FLAGS_enable_write_thread_adaptive_yield;
+    options.enable_pipelined_write = FLAGS_enable_pipelined_write;
+    options.write_thread_max_yield_usec = FLAGS_write_thread_max_yield_usec;
+    options.write_thread_slow_yield_usec = FLAGS_write_thread_slow_yield_usec;
+    options.rate_limit_delay_max_milliseconds =
+      FLAGS_rate_limit_delay_max_milliseconds;
+    options.table_cache_numshardbits = FLAGS_table_cache_numshardbits;
+    options.max_compaction_bytes = FLAGS_max_compaction_bytes;
+    options.disable_auto_compactions = FLAGS_disable_auto_compactions;
+    options.optimize_filters_for_hits = FLAGS_optimize_filters_for_hits;
+
+    // fill storage options
+    options.advise_random_on_open = FLAGS_advise_random_on_open;
+    options.access_hint_on_compaction_start = FLAGS_compaction_fadvice_e;
+    options.use_adaptive_mutex = FLAGS_use_adaptive_mutex;
+    options.bytes_per_sync = FLAGS_bytes_per_sync;
+    options.wal_bytes_per_sync = FLAGS_wal_bytes_per_sync;
+
+    // merge operator options
+    options.merge_operator = MergeOperators::CreateFromStringId(
+        FLAGS_merge_operator);
+    if (options.merge_operator == nullptr && !FLAGS_merge_operator.empty()) {
+      fprintf(stderr, "invalid merge operator: %s\n",
+              FLAGS_merge_operator.c_str());
+      exit(1);
+    }
+    options.max_successive_merges = FLAGS_max_successive_merges;
+    options.report_bg_io_stats = FLAGS_report_bg_io_stats;
+
+    // set universal style compaction configurations, if applicable
+    if (FLAGS_universal_size_ratio != 0) {
+      options.compaction_options_universal.size_ratio =
+        FLAGS_universal_size_ratio;
+    }
+    if (FLAGS_universal_min_merge_width != 0) {
+      options.compaction_options_universal.min_merge_width =
+        FLAGS_universal_min_merge_width;
+    }
+    if (FLAGS_universal_max_merge_width != 0) {
+      options.compaction_options_universal.max_merge_width =
+        FLAGS_universal_max_merge_width;
+    }
+    if (FLAGS_universal_max_size_amplification_percent != 0) {
+      options.compaction_options_universal.max_size_amplification_percent =
+        FLAGS_universal_max_size_amplification_percent;
+    }
+    if (FLAGS_universal_compression_size_percent != -1) {
+      options.compaction_options_universal.compression_size_percent =
+        FLAGS_universal_compression_size_percent;
+    }
+    options.compaction_options_universal.allow_trivial_move =
+        FLAGS_universal_allow_trivial_move;
+    if (FLAGS_thread_status_per_interval > 0) {
+      options.enable_thread_tracking = true;
+    }
+
+#ifndef ROCKSDB_LITE
+    if (FLAGS_readonly && FLAGS_transaction_db) {
+      fprintf(stderr, "Cannot use readonly flag with transaction_db\n");
+      exit(1);
+    }
+#endif  // ROCKSDB_LITE
+
+  }
+
+  void InitializeOptionsGeneral(Options* opts) {
+    Options& options = *opts;
+
+    options.create_missing_column_families = FLAGS_num_column_families > 1;
+    options.statistics = dbstats;
+    options.wal_dir = FLAGS_wal_dir;
+    options.create_if_missing = !FLAGS_use_existing_db;
+    options.dump_malloc_stats = FLAGS_dump_malloc_stats;
+    options.stats_dump_period_sec =
+        static_cast<unsigned int>(FLAGS_stats_dump_period_sec);
+    options.stats_persist_period_sec =
+        static_cast<unsigned int>(FLAGS_stats_persist_period_sec);
+    options.stats_history_buffer_size =
+        static_cast<size_t>(FLAGS_stats_history_buffer_size);
+
+    options.compression_opts.level = FLAGS_compression_level;
+    options.compression_opts.max_dict_bytes = FLAGS_compression_max_dict_bytes;
+    options.compression_opts.zstd_max_train_bytes =
+        FLAGS_compression_zstd_max_train_bytes;
+    // If this is a block based table, set some related options
+    if (options.table_factory->Name() == BlockBasedTableFactory::kName &&
+        options.table_factory->GetOptions() != nullptr) {
+      BlockBasedTableOptions* table_options =
+          reinterpret_cast<BlockBasedTableOptions*>(
+              options.table_factory->GetOptions());
+      if (FLAGS_cache_size) {
+        table_options->block_cache = cache_;
+      }
+      if (FLAGS_bloom_bits >= 0) {
+        table_options->filter_policy.reset(NewBloomFilterPolicy(
+            FLAGS_bloom_bits, FLAGS_use_block_based_filter));
+      }
+    }
+    if (FLAGS_row_cache_size) {
+      if (FLAGS_cache_numshardbits >= 1) {
+        options.row_cache =
+            NewLRUCache(FLAGS_row_cache_size, FLAGS_cache_numshardbits);
+      } else {
+        options.row_cache = NewLRUCache(FLAGS_row_cache_size);
+      }
+    }
+    if (FLAGS_enable_io_prio) {
+      FLAGS_env->LowerThreadPoolIOPriority(Env::LOW);
+      FLAGS_env->LowerThreadPoolIOPriority(Env::HIGH);
+    }
+    if (FLAGS_enable_cpu_prio) {
+      FLAGS_env->LowerThreadPoolCPUPriority(Env::LOW);
+      FLAGS_env->LowerThreadPoolCPUPriority(Env::HIGH);
+    }
+    options.env = FLAGS_env;
+    if (FLAGS_sine_write_rate) {
+      FLAGS_benchmark_write_rate_limit = static_cast<uint64_t>(SineRate(0));
+    }
+
+    if (FLAGS_rate_limiter_bytes_per_sec > 0) {
+      if (FLAGS_rate_limit_bg_reads &&
+          !FLAGS_new_table_reader_for_compaction_inputs) {
+        fprintf(stderr,
+                "rate limit compaction reads must have "
+                "new_table_reader_for_compaction_inputs set\n");
+        exit(1);
+      }
+      options.rate_limiter.reset(NewGenericRateLimiter(
+          FLAGS_rate_limiter_bytes_per_sec, 100 * 1000 /* refill_period_us */,
+          10 /* fairness */,
+          FLAGS_rate_limit_bg_reads ? RateLimiter::Mode::kReadsOnly
+                                    : RateLimiter::Mode::kWritesOnly,
+          FLAGS_rate_limiter_auto_tuned));
+    }
+
+    options.listeners.emplace_back(listener_);
+    if (FLAGS_num_multi_db <= 1) {
+      OpenDb(options, FLAGS_db, &db_);
+    } else {
+      multi_dbs_.clear();
+      multi_dbs_.resize(FLAGS_num_multi_db);
+      auto wal_dir = options.wal_dir;
+      for (int i = 0; i < FLAGS_num_multi_db; i++) {
+        if (!wal_dir.empty()) {
+          options.wal_dir = GetPathForMultiple(wal_dir, i);
+        }
+        OpenDb(options, GetPathForMultiple(FLAGS_db, i), &multi_dbs_[i]);
+      }
+      options.wal_dir = wal_dir;
+    }
+
+    // KeepFilter is a noop filter, this can be used to test compaction filter
+    if (FLAGS_use_keep_filter) {
+      options.compaction_filter = new KeepFilter();
+      fprintf(stdout, "A noop compaction filter is used\n");
+    }
+
+    if (FLAGS_use_existing_keys) {
+      // Only work on single database
+      assert(db_.db != nullptr);
+      ReadOptions read_opts;
+      read_opts.total_order_seek = true;
+      Iterator* iter = db_.db->NewIterator(read_opts);
+      for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
+        keys_.emplace_back(iter->key().ToString());
+      }
+      delete iter;
+      FLAGS_num = keys_.size();
+    }
+  }
+
+  void Open(Options* opts) {
+    if (!InitializeOptionsFromFile(opts)) {
+      InitializeOptionsFromFlags(opts);
+    }
+
+    InitializeOptionsGeneral(opts);
+  }
+
+  void OpenDb(Options options, const std::string& db_name,
+      DBWithColumnFamilies* db) {
+    Status s;
+    // Open with column families if necessary.
+    if (FLAGS_num_column_families > 1) {
+      size_t num_hot = FLAGS_num_column_families;
+      if (FLAGS_num_hot_column_families > 0 &&
+          FLAGS_num_hot_column_families < FLAGS_num_column_families) {
+        num_hot = FLAGS_num_hot_column_families;
+      } else {
+        FLAGS_num_hot_column_families = FLAGS_num_column_families;
+      }
+      std::vector<ColumnFamilyDescriptor> column_families;
+      for (size_t i = 0; i < num_hot; i++) {
+        column_families.push_back(ColumnFamilyDescriptor(
+              ColumnFamilyName(i), ColumnFamilyOptions(options)));
+      }
+      std::vector<int> cfh_idx_to_prob;
+      if (!FLAGS_column_family_distribution.empty()) {
+        std::stringstream cf_prob_stream(FLAGS_column_family_distribution);
+        std::string cf_prob;
+        int sum = 0;
+        while (std::getline(cf_prob_stream, cf_prob, ',')) {
+          cfh_idx_to_prob.push_back(std::stoi(cf_prob));
+          sum += cfh_idx_to_prob.back();
+        }
+        if (sum != 100) {
+          fprintf(stderr, "column_family_distribution items must sum to 100\n");
+          exit(1);
+        }
+        if (cfh_idx_to_prob.size() != num_hot) {
+          fprintf(stderr,
+                  "got %" ROCKSDB_PRIszt
+                  " column_family_distribution items; expected "
+                  "%" ROCKSDB_PRIszt "\n",
+                  cfh_idx_to_prob.size(), num_hot);
+          exit(1);
+        }
+      }
+#ifndef ROCKSDB_LITE
+      if (FLAGS_readonly) {
+        s = DB::OpenForReadOnly(options, db_name, column_families,
+            &db->cfh, &db->db);
+      } else if (FLAGS_optimistic_transaction_db) {
+        s = OptimisticTransactionDB::Open(options, db_name, column_families,
+                                          &db->cfh, &db->opt_txn_db);
+        if (s.ok()) {
+          db->db = db->opt_txn_db->GetBaseDB();
+        }
+      } else if (FLAGS_transaction_db) {
+        TransactionDB* ptr;
+        TransactionDBOptions txn_db_options;
+        s = TransactionDB::Open(options, txn_db_options, db_name,
+                                column_families, &db->cfh, &ptr);
+        if (s.ok()) {
+          db->db = ptr;
+        }
+      } else {
+        s = DB::Open(options, db_name, column_families, &db->cfh, &db->db);
+      }
+#else
+      s = DB::Open(options, db_name, column_families, &db->cfh, &db->db);
+#endif  // ROCKSDB_LITE
+      db->cfh.resize(FLAGS_num_column_families);
+      db->num_created = num_hot;
+      db->num_hot = num_hot;
+      db->cfh_idx_to_prob = std::move(cfh_idx_to_prob);
+#ifndef ROCKSDB_LITE
+    } else if (FLAGS_readonly) {
+      s = DB::OpenForReadOnly(options, db_name, &db->db);
+    } else if (FLAGS_optimistic_transaction_db) {
+      s = OptimisticTransactionDB::Open(options, db_name, &db->opt_txn_db);
+      if (s.ok()) {
+        db->db = db->opt_txn_db->GetBaseDB();
+      }
+    } else if (FLAGS_transaction_db) {
+      TransactionDB* ptr = nullptr;
+      TransactionDBOptions txn_db_options;
+      s = CreateLoggerFromOptions(db_name, options, &options.info_log);
+      if (s.ok()) {
+        s = TransactionDB::Open(options, txn_db_options, db_name, &ptr);
+      }
+      if (s.ok()) {
+        db->db = ptr;
+      }
+    } else if (FLAGS_use_blob_db) {
+      blob_db::BlobDBOptions blob_db_options;
+      blob_db_options.enable_garbage_collection = FLAGS_blob_db_enable_gc;
+      blob_db_options.is_fifo = FLAGS_blob_db_is_fifo;
+      blob_db_options.max_db_size = FLAGS_blob_db_max_db_size;
+      blob_db_options.ttl_range_secs = FLAGS_blob_db_ttl_range_secs;
+      blob_db_options.min_blob_size = FLAGS_blob_db_min_blob_size;
+      blob_db_options.bytes_per_sync = FLAGS_blob_db_bytes_per_sync;
+      blob_db_options.blob_file_size = FLAGS_blob_db_file_size;
+      blob_db::BlobDB* ptr = nullptr;
+      s = blob_db::BlobDB::Open(options, blob_db_options, db_name, &ptr);
+      if (s.ok()) {
+        db->db = ptr;
+      }
+#endif  // ROCKSDB_LITE
+    } else {
+      s = DB::Open(options, db_name, &db->db);
+    }
+    if (!s.ok()) {
+      fprintf(stderr, "open error: %s\n", s.ToString().c_str());
+      exit(1);
+    }
+  }
+
+  enum WriteMode {
+    RANDOM, SEQUENTIAL, UNIQUE_RANDOM
+  };
+
+  void WriteSeqDeterministic(ThreadState* thread) {
+    DoDeterministicCompact(thread, open_options_.compaction_style, SEQUENTIAL);
+  }
+
+  void WriteUniqueRandomDeterministic(ThreadState* thread) {
+    DoDeterministicCompact(thread, open_options_.compaction_style,
+                           UNIQUE_RANDOM);
+  }
+
+  void WriteSeq(ThreadState* thread) {
+    DoWrite(thread, SEQUENTIAL);
+  }
+
+  void WriteRandom(ThreadState* thread) {
+    DoWrite(thread, RANDOM);
+  }
+
+  void WriteUniqueRandom(ThreadState* thread) {
+    DoWrite(thread, UNIQUE_RANDOM);
+  }
+
+  class KeyGenerator {
+   public:
+    KeyGenerator(Random64* rand, WriteMode mode, uint64_t num,
+                 uint64_t /*num_per_set*/ = 64 * 1024)
+        : rand_(rand), mode_(mode), num_(num), next_(0) {
+      if (mode_ == UNIQUE_RANDOM) {
+        // NOTE: if memory consumption of this approach becomes a concern,
+        // we can either break it into pieces and only random shuffle a section
+        // each time. Alternatively, use a bit map implementation
+        // (https://reviews.facebook.net/differential/diff/54627/)
+        values_.resize(num_);
+        for (uint64_t i = 0; i < num_; ++i) {
+          values_[i] = i;
+        }
+        std::shuffle(
+            values_.begin(), values_.end(),
+            std::default_random_engine(static_cast<unsigned int>(FLAGS_seed)));
+      }
+    }
+
+    uint64_t Next() {
+      switch (mode_) {
+        case SEQUENTIAL:
+          return next_++;
+        case RANDOM:
+          return rand_->Next() % num_;
+        case UNIQUE_RANDOM:
+          assert(next_ < num_);
+          return values_[next_++];
+      }
+      assert(false);
+      return std::numeric_limits<uint64_t>::max();
+    }
+
+   private:
+    Random64* rand_;
+    WriteMode mode_;
+    const uint64_t num_;
+    uint64_t next_;
+    std::vector<uint64_t> values_;
+  };
+
+  DB* SelectDB(ThreadState* thread) {
+    return SelectDBWithCfh(thread)->db;
+  }
+
+  DBWithColumnFamilies* SelectDBWithCfh(ThreadState* thread) {
+    return SelectDBWithCfh(thread->rand.Next());
+  }
+
+  DBWithColumnFamilies* SelectDBWithCfh(uint64_t rand_int) {
+    if (db_.db != nullptr) {
+      return &db_;
+    } else  {
+      return &multi_dbs_[rand_int % multi_dbs_.size()];
+    }
+  }
+
+  double SineRate(double x) {
+    return FLAGS_sine_a*sin((FLAGS_sine_b*x) + FLAGS_sine_c) + FLAGS_sine_d;
+  }
+
+  void DoWrite(ThreadState* thread, WriteMode write_mode) {
+    const int test_duration = write_mode == RANDOM ? FLAGS_duration : 0;
+    const int64_t num_ops = writes_ == 0 ? num_ : writes_;
+
+    size_t num_key_gens = 1;
+    if (db_.db == nullptr) {
+      num_key_gens = multi_dbs_.size();
+    }
+    std::vector<std::unique_ptr<KeyGenerator>> key_gens(num_key_gens);
+    int64_t max_ops = num_ops * num_key_gens;
+    int64_t ops_per_stage = max_ops;
+    if (FLAGS_num_column_families > 1 && FLAGS_num_hot_column_families > 0) {
+      ops_per_stage = (max_ops - 1) / (FLAGS_num_column_families /
+                                       FLAGS_num_hot_column_families) +
+                      1;
+    }
+
+    Duration duration(test_duration, max_ops, ops_per_stage);
+    for (size_t i = 0; i < num_key_gens; i++) {
+      key_gens[i].reset(new KeyGenerator(&(thread->rand), write_mode,
+                                         num_ + max_num_range_tombstones_,
+                                         ops_per_stage));
+    }
+
+    if (num_ != FLAGS_num) {
+      char msg[100];
+      snprintf(msg, sizeof(msg), "(%" PRIu64 " ops)", num_);
+      thread->stats.AddMessage(msg);
+    }
+
+    RandomGenerator gen;
+    WriteBatch batch;
+    Status s;
+    int64_t bytes = 0;
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    std::unique_ptr<const char[]> begin_key_guard;
+    Slice begin_key = AllocateKey(&begin_key_guard);
+    std::unique_ptr<const char[]> end_key_guard;
+    Slice end_key = AllocateKey(&end_key_guard);
+    std::vector<std::unique_ptr<const char[]>> expanded_key_guards;
+    std::vector<Slice> expanded_keys;
+    if (FLAGS_expand_range_tombstones) {
+      expanded_key_guards.resize(range_tombstone_width_);
+      for (auto& expanded_key_guard : expanded_key_guards) {
+        expanded_keys.emplace_back(AllocateKey(&expanded_key_guard));
+      }
+    }
+
+    int64_t stage = 0;
+    int64_t num_written = 0;
+    while (!duration.Done(entries_per_batch_)) {
+      if (duration.GetStage() != stage) {
+        stage = duration.GetStage();
+        if (db_.db != nullptr) {
+          db_.CreateNewCf(open_options_, stage);
+        } else {
+          for (auto& db : multi_dbs_) {
+            db.CreateNewCf(open_options_, stage);
+          }
+        }
+      }
+
+      size_t id = thread->rand.Next() % num_key_gens;
+      DBWithColumnFamilies* db_with_cfh = SelectDBWithCfh(id);
+      batch.Clear();
+
+      if (thread->shared->write_rate_limiter.get() != nullptr) {
+        thread->shared->write_rate_limiter->Request(
+            entries_per_batch_ * (value_size_ + key_size_), Env::IO_HIGH,
+            nullptr /* stats */, RateLimiter::OpType::kWrite);
+        // Set time at which last op finished to Now() to hide latency and
+        // sleep from rate limiter. Also, do the check once per batch, not
+        // once per write.
+        thread->stats.ResetLastOpTime();
+      }
+
+      for (int64_t j = 0; j < entries_per_batch_; j++) {
+        int64_t rand_num = key_gens[id]->Next();
+        GenerateKeyFromInt(rand_num, FLAGS_num, &key);
+        if (use_blob_db_) {
+#ifndef ROCKSDB_LITE
+          Slice val = gen.Generate(value_size_);
+          int ttl = rand() % FLAGS_blob_db_max_ttl_range;
+          blob_db::BlobDB* blobdb =
+              static_cast<blob_db::BlobDB*>(db_with_cfh->db);
+          s = blobdb->PutWithTTL(write_options_, key, val, ttl);
+#endif  //  ROCKSDB_LITE
+        } else if (FLAGS_num_column_families <= 1) {
+          batch.Put(key, gen.Generate(value_size_));
+        } else {
+          // We use same rand_num as seed for key and column family so that we
+          // can deterministically find the cfh corresponding to a particular
+          // key while reading the key.
+          batch.Put(db_with_cfh->GetCfh(rand_num), key,
+                    gen.Generate(value_size_));
+        }
+        bytes += value_size_ + key_size_;
+        ++num_written;
+        if (writes_per_range_tombstone_ > 0 &&
+            num_written > writes_before_delete_range_ &&
+            (num_written - writes_before_delete_range_) /
+                    writes_per_range_tombstone_ <=
+                max_num_range_tombstones_ &&
+            (num_written - writes_before_delete_range_) %
+                    writes_per_range_tombstone_ ==
+                0) {
+          int64_t begin_num = key_gens[id]->Next();
+          if (FLAGS_expand_range_tombstones) {
+            for (int64_t offset = 0; offset < range_tombstone_width_;
+                 ++offset) {
+              GenerateKeyFromInt(begin_num + offset, FLAGS_num,
+                                 &expanded_keys[offset]);
+              if (use_blob_db_) {
+#ifndef ROCKSDB_LITE
+                s = db_with_cfh->db->Delete(write_options_,
+                                            expanded_keys[offset]);
+#endif  //  ROCKSDB_LITE
+              } else if (FLAGS_num_column_families <= 1) {
+                batch.Delete(expanded_keys[offset]);
+              } else {
+                batch.Delete(db_with_cfh->GetCfh(rand_num),
+                             expanded_keys[offset]);
+              }
+            }
+          } else {
+            GenerateKeyFromInt(begin_num, FLAGS_num, &begin_key);
+            GenerateKeyFromInt(begin_num + range_tombstone_width_, FLAGS_num,
+                               &end_key);
+            if (use_blob_db_) {
+#ifndef ROCKSDB_LITE
+              s = db_with_cfh->db->DeleteRange(
+                  write_options_, db_with_cfh->db->DefaultColumnFamily(),
+                  begin_key, end_key);
+#endif  //  ROCKSDB_LITE
+            } else if (FLAGS_num_column_families <= 1) {
+              batch.DeleteRange(begin_key, end_key);
+            } else {
+              batch.DeleteRange(db_with_cfh->GetCfh(rand_num), begin_key,
+                                end_key);
+            }
+          }
+        }
+      }
+      if (!use_blob_db_) {
+        s = db_with_cfh->db->Write(write_options_, &batch);
+      }
+      thread->stats.FinishedOps(db_with_cfh, db_with_cfh->db,
+                                entries_per_batch_, kWrite);
+      if (FLAGS_sine_write_rate) {
+        uint64_t now = FLAGS_env->NowMicros();
+
+        uint64_t usecs_since_last;
+        if (now > thread->stats.GetSineInterval()) {
+          usecs_since_last = now - thread->stats.GetSineInterval();
+        } else {
+          usecs_since_last = 0;
+        }
+
+        if (usecs_since_last >
+            (FLAGS_sine_write_rate_interval_milliseconds * uint64_t{1000})) {
+          double usecs_since_start =
+                  static_cast<double>(now - thread->stats.GetStart());
+          thread->stats.ResetSineInterval();
+          uint64_t write_rate =
+                  static_cast<uint64_t>(SineRate(usecs_since_start / 1000000.0));
+          thread->shared->write_rate_limiter.reset(
+                  NewGenericRateLimiter(write_rate));
+        }
+      }
+      if (!s.ok()) {
+        s = listener_->WaitForRecovery(600000000) ? Status::OK() : s;
+      }
+
+      if (!s.ok()) {
+        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+    }
+    thread->stats.AddBytes(bytes);
+  }
+
+  Status DoDeterministicCompact(ThreadState* thread,
+                                CompactionStyle compaction_style,
+                                WriteMode write_mode) {
+#ifndef ROCKSDB_LITE
+    ColumnFamilyMetaData meta;
+    std::vector<DB*> db_list;
+    if (db_.db != nullptr) {
+      db_list.push_back(db_.db);
+    } else {
+      for (auto& db : multi_dbs_) {
+        db_list.push_back(db.db);
+      }
+    }
+    std::vector<Options> options_list;
+    for (auto db : db_list) {
+      options_list.push_back(db->GetOptions());
+      if (compaction_style != kCompactionStyleFIFO) {
+        db->SetOptions({{"disable_auto_compactions", "1"},
+                        {"level0_slowdown_writes_trigger", "400000000"},
+                        {"level0_stop_writes_trigger", "400000000"}});
+      } else {
+        db->SetOptions({{"disable_auto_compactions", "1"}});
+      }
+    }
+
+    assert(!db_list.empty());
+    auto num_db = db_list.size();
+    size_t num_levels = static_cast<size_t>(open_options_.num_levels);
+    size_t output_level = open_options_.num_levels - 1;
+    std::vector<std::vector<std::vector<SstFileMetaData>>> sorted_runs(num_db);
+    std::vector<size_t> num_files_at_level0(num_db, 0);
+    if (compaction_style == kCompactionStyleLevel) {
+      if (num_levels == 0) {
+        return Status::InvalidArgument("num_levels should be larger than 1");
+      }
+      bool should_stop = false;
+      while (!should_stop) {
+        if (sorted_runs[0].empty()) {
+          DoWrite(thread, write_mode);
+        } else {
+          DoWrite(thread, UNIQUE_RANDOM);
+        }
+        for (size_t i = 0; i < num_db; i++) {
+          auto db = db_list[i];
+          db->Flush(FlushOptions());
+          db->GetColumnFamilyMetaData(&meta);
+          if (num_files_at_level0[i] == meta.levels[0].files.size() ||
+              writes_ == 0) {
+            should_stop = true;
+            continue;
+          }
+          sorted_runs[i].emplace_back(
+              meta.levels[0].files.begin(),
+              meta.levels[0].files.end() - num_files_at_level0[i]);
+          num_files_at_level0[i] = meta.levels[0].files.size();
+          if (sorted_runs[i].back().size() == 1) {
+            should_stop = true;
+            continue;
+          }
+          if (sorted_runs[i].size() == output_level) {
+            auto& L1 = sorted_runs[i].back();
+            L1.erase(L1.begin(), L1.begin() + L1.size() / 3);
+            should_stop = true;
+            continue;
+          }
+        }
+        writes_ /= static_cast<int64_t>(open_options_.max_bytes_for_level_multiplier);
+      }
+      for (size_t i = 0; i < num_db; i++) {
+        if (sorted_runs[i].size() < num_levels - 1) {
+          fprintf(stderr, "n is too small to fill %" ROCKSDB_PRIszt " levels\n", num_levels);
+          exit(1);
+        }
+      }
+      for (size_t i = 0; i < num_db; i++) {
+        auto db = db_list[i];
+        auto compactionOptions = CompactionOptions();
+        compactionOptions.compression = FLAGS_compression_type_e;
+        auto options = db->GetOptions();
+        MutableCFOptions mutable_cf_options(options);
+        for (size_t j = 0; j < sorted_runs[i].size(); j++) {
+          compactionOptions.output_file_size_limit =
+              MaxFileSizeForLevel(mutable_cf_options,
+                  static_cast<int>(output_level), compaction_style);
+          std::cout << sorted_runs[i][j].size() << std::endl;
+          db->CompactFiles(compactionOptions, {sorted_runs[i][j].back().name,
+                                               sorted_runs[i][j].front().name},
+                           static_cast<int>(output_level - j) /*level*/);
+        }
+      }
+    } else if (compaction_style == kCompactionStyleUniversal) {
+      auto ratio = open_options_.compaction_options_universal.size_ratio;
+      bool should_stop = false;
+      while (!should_stop) {
+        if (sorted_runs[0].empty()) {
+          DoWrite(thread, write_mode);
+        } else {
+          DoWrite(thread, UNIQUE_RANDOM);
+        }
+        for (size_t i = 0; i < num_db; i++) {
+          auto db = db_list[i];
+          db->Flush(FlushOptions());
+          db->GetColumnFamilyMetaData(&meta);
+          if (num_files_at_level0[i] == meta.levels[0].files.size() ||
+              writes_ == 0) {
+            should_stop = true;
+            continue;
+          }
+          sorted_runs[i].emplace_back(
+              meta.levels[0].files.begin(),
+              meta.levels[0].files.end() - num_files_at_level0[i]);
+          num_files_at_level0[i] = meta.levels[0].files.size();
+          if (sorted_runs[i].back().size() == 1) {
+            should_stop = true;
+            continue;
+          }
+          num_files_at_level0[i] = meta.levels[0].files.size();
+        }
+        writes_ =  static_cast<int64_t>(writes_* static_cast<double>(100) / (ratio + 200));
+      }
+      for (size_t i = 0; i < num_db; i++) {
+        if (sorted_runs[i].size() < num_levels) {
+          fprintf(stderr, "n is too small to fill %" ROCKSDB_PRIszt  " levels\n", num_levels);
+          exit(1);
+        }
+      }
+      for (size_t i = 0; i < num_db; i++) {
+        auto db = db_list[i];
+        auto compactionOptions = CompactionOptions();
+        compactionOptions.compression = FLAGS_compression_type_e;
+        auto options = db->GetOptions();
+        MutableCFOptions mutable_cf_options(options);
+        for (size_t j = 0; j < sorted_runs[i].size(); j++) {
+          compactionOptions.output_file_size_limit =
+              MaxFileSizeForLevel(mutable_cf_options,
+                  static_cast<int>(output_level), compaction_style);
+          db->CompactFiles(
+              compactionOptions,
+              {sorted_runs[i][j].back().name, sorted_runs[i][j].front().name},
+              (output_level > j ? static_cast<int>(output_level - j)
+                                : 0) /*level*/);
+        }
+      }
+    } else if (compaction_style == kCompactionStyleFIFO) {
+      if (num_levels != 1) {
+        return Status::InvalidArgument(
+          "num_levels should be 1 for FIFO compaction");
+      }
+      if (FLAGS_num_multi_db != 0) {
+        return Status::InvalidArgument("Doesn't support multiDB");
+      }
+      auto db = db_list[0];
+      std::vector<std::string> file_names;
+      while (true) {
+        if (sorted_runs[0].empty()) {
+          DoWrite(thread, write_mode);
+        } else {
+          DoWrite(thread, UNIQUE_RANDOM);
+        }
+        db->Flush(FlushOptions());
+        db->GetColumnFamilyMetaData(&meta);
+        auto total_size = meta.levels[0].size;
+        if (total_size >=
+          db->GetOptions().compaction_options_fifo.max_table_files_size) {
+          for (auto file_meta : meta.levels[0].files) {
+            file_names.emplace_back(file_meta.name);
+          }
+          break;
+        }
+      }
+      // TODO(shuzhang1989): Investigate why CompactFiles not working
+      // auto compactionOptions = CompactionOptions();
+      // db->CompactFiles(compactionOptions, file_names, 0);
+      auto compactionOptions = CompactRangeOptions();
+      db->CompactRange(compactionOptions, nullptr, nullptr);
+    } else {
+      fprintf(stdout,
+              "%-12s : skipped (-compaction_stype=kCompactionStyleNone)\n",
+              "filldeterministic");
+      return Status::InvalidArgument("None compaction is not supported");
+    }
+
+// Verify seqno and key range
+// Note: the seqno get changed at the max level by implementation
+// optimization, so skip the check of the max level.
+#ifndef NDEBUG
+    for (size_t k = 0; k < num_db; k++) {
+      auto db = db_list[k];
+      db->GetColumnFamilyMetaData(&meta);
+      // verify the number of sorted runs
+      if (compaction_style == kCompactionStyleLevel) {
+        assert(num_levels - 1 == sorted_runs[k].size());
+      } else if (compaction_style == kCompactionStyleUniversal) {
+        assert(meta.levels[0].files.size() + num_levels - 1 ==
+               sorted_runs[k].size());
+      } else if (compaction_style == kCompactionStyleFIFO) {
+        // TODO(gzh): FIFO compaction
+        db->GetColumnFamilyMetaData(&meta);
+        auto total_size = meta.levels[0].size;
+        assert(total_size <=
+          db->GetOptions().compaction_options_fifo.max_table_files_size);
+          break;
+      }
+
+      // verify smallest/largest seqno and key range of each sorted run
+      auto max_level = num_levels - 1;
+      int level;
+      for (size_t i = 0; i < sorted_runs[k].size(); i++) {
+        level = static_cast<int>(max_level - i);
+        SequenceNumber sorted_run_smallest_seqno = kMaxSequenceNumber;
+        SequenceNumber sorted_run_largest_seqno = 0;
+        std::string sorted_run_smallest_key, sorted_run_largest_key;
+        bool first_key = true;
+        for (auto fileMeta : sorted_runs[k][i]) {
+          sorted_run_smallest_seqno =
+              std::min(sorted_run_smallest_seqno, fileMeta.smallest_seqno);
+          sorted_run_largest_seqno =
+              std::max(sorted_run_largest_seqno, fileMeta.largest_seqno);
+          if (first_key ||
+              db->DefaultColumnFamily()->GetComparator()->Compare(
+                  fileMeta.smallestkey, sorted_run_smallest_key) < 0) {
+            sorted_run_smallest_key = fileMeta.smallestkey;
+          }
+          if (first_key ||
+              db->DefaultColumnFamily()->GetComparator()->Compare(
+                  fileMeta.largestkey, sorted_run_largest_key) > 0) {
+            sorted_run_largest_key = fileMeta.largestkey;
+          }
+          first_key = false;
+        }
+        if (compaction_style == kCompactionStyleLevel ||
+            (compaction_style == kCompactionStyleUniversal && level > 0)) {
+          SequenceNumber level_smallest_seqno = kMaxSequenceNumber;
+          SequenceNumber level_largest_seqno = 0;
+          for (auto fileMeta : meta.levels[level].files) {
+            level_smallest_seqno =
+                std::min(level_smallest_seqno, fileMeta.smallest_seqno);
+            level_largest_seqno =
+                std::max(level_largest_seqno, fileMeta.largest_seqno);
+          }
+          assert(sorted_run_smallest_key ==
+                 meta.levels[level].files.front().smallestkey);
+          assert(sorted_run_largest_key ==
+                 meta.levels[level].files.back().largestkey);
+          if (level != static_cast<int>(max_level)) {
+            // compaction at max_level would change sequence number
+            assert(sorted_run_smallest_seqno == level_smallest_seqno);
+            assert(sorted_run_largest_seqno == level_largest_seqno);
+          }
+        } else if (compaction_style == kCompactionStyleUniversal) {
+          // level <= 0 means sorted runs on level 0
+          auto level0_file =
+              meta.levels[0].files[sorted_runs[k].size() - 1 - i];
+          assert(sorted_run_smallest_key == level0_file.smallestkey);
+          assert(sorted_run_largest_key == level0_file.largestkey);
+          if (level != static_cast<int>(max_level)) {
+            assert(sorted_run_smallest_seqno == level0_file.smallest_seqno);
+            assert(sorted_run_largest_seqno == level0_file.largest_seqno);
+          }
+        }
+      }
+    }
+#endif
+    // print the size of each sorted_run
+    for (size_t k = 0; k < num_db; k++) {
+      auto db = db_list[k];
+      fprintf(stdout,
+              "---------------------- DB %" ROCKSDB_PRIszt " LSM ---------------------\n", k);
+      db->GetColumnFamilyMetaData(&meta);
+      for (auto& levelMeta : meta.levels) {
+        if (levelMeta.files.empty()) {
+          continue;
+        }
+        if (levelMeta.level == 0) {
+          for (auto& fileMeta : levelMeta.files) {
+            fprintf(stdout, "Level[%d]: %s(size: %" ROCKSDB_PRIszt " bytes)\n",
+                    levelMeta.level, fileMeta.name.c_str(), fileMeta.size);
+          }
+        } else {
+          fprintf(stdout, "Level[%d]: %s - %s(total size: %" PRIi64 " bytes)\n",
+                  levelMeta.level, levelMeta.files.front().name.c_str(),
+                  levelMeta.files.back().name.c_str(), levelMeta.size);
+        }
+      }
+    }
+    for (size_t i = 0; i < num_db; i++) {
+      db_list[i]->SetOptions(
+          {{"disable_auto_compactions",
+            std::to_string(options_list[i].disable_auto_compactions)},
+           {"level0_slowdown_writes_trigger",
+            std::to_string(options_list[i].level0_slowdown_writes_trigger)},
+           {"level0_stop_writes_trigger",
+            std::to_string(options_list[i].level0_stop_writes_trigger)}});
+    }
+    return Status::OK();
+#else
+    (void)thread;
+    (void)compaction_style;
+    (void)write_mode;
+    fprintf(stderr, "Rocksdb Lite doesn't support filldeterministic\n");
+    return Status::NotSupported(
+        "Rocksdb Lite doesn't support filldeterministic");
+#endif  // ROCKSDB_LITE
+  }
+
+  void ReadSequential(ThreadState* thread) {
+    if (db_.db != nullptr) {
+      ReadSequential(thread, db_.db);
+    } else {
+      for (const auto& db_with_cfh : multi_dbs_) {
+        ReadSequential(thread, db_with_cfh.db);
+      }
+    }
+  }
+
+  void ReadSequential(ThreadState* thread, DB* db) {
+    ReadOptions options(FLAGS_verify_checksum, true);
+    options.tailing = FLAGS_use_tailing_iterator;
+
+    Iterator* iter = db->NewIterator(options);
+    int64_t i = 0;
+    int64_t bytes = 0;
+    for (iter->SeekToFirst(); i < reads_ && iter->Valid(); iter->Next()) {
+      bytes += iter->key().size() + iter->value().size();
+      thread->stats.FinishedOps(nullptr, db, 1, kRead);
+      ++i;
+
+      if (thread->shared->read_rate_limiter.get() != nullptr &&
+          i % 1024 == 1023) {
+        thread->shared->read_rate_limiter->Request(1024, Env::IO_HIGH,
+                                                   nullptr /* stats */,
+                                                   RateLimiter::OpType::kRead);
+      }
+    }
+
+    delete iter;
+    thread->stats.AddBytes(bytes);
+    if (FLAGS_perf_level > rocksdb::PerfLevel::kDisable) {
+      thread->stats.AddMessage(std::string("PERF_CONTEXT:\n") +
+                               get_perf_context()->ToString());
+    }
+  }
+
+  void ReadReverse(ThreadState* thread) {
+    if (db_.db != nullptr) {
+      ReadReverse(thread, db_.db);
+    } else {
+      for (const auto& db_with_cfh : multi_dbs_) {
+        ReadReverse(thread, db_with_cfh.db);
+      }
+    }
+  }
+
+  void ReadReverse(ThreadState* thread, DB* db) {
+    Iterator* iter = db->NewIterator(ReadOptions(FLAGS_verify_checksum, true));
+    int64_t i = 0;
+    int64_t bytes = 0;
+    for (iter->SeekToLast(); i < reads_ && iter->Valid(); iter->Prev()) {
+      bytes += iter->key().size() + iter->value().size();
+      thread->stats.FinishedOps(nullptr, db, 1, kRead);
+      ++i;
+      if (thread->shared->read_rate_limiter.get() != nullptr &&
+          i % 1024 == 1023) {
+        thread->shared->read_rate_limiter->Request(1024, Env::IO_HIGH,
+                                                   nullptr /* stats */,
+                                                   RateLimiter::OpType::kRead);
+      }
+    }
+    delete iter;
+    thread->stats.AddBytes(bytes);
+  }
+
+  void ReadRandomFast(ThreadState* thread) {
+    int64_t read = 0;
+    int64_t found = 0;
+    int64_t nonexist = 0;
+    ReadOptions options(FLAGS_verify_checksum, true);
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    std::string value;
+    DB* db = SelectDBWithCfh(thread)->db;
+
+    int64_t pot = 1;
+    while (pot < FLAGS_num) {
+      pot <<= 1;
+    }
+
+    Duration duration(FLAGS_duration, reads_);
+    do {
+      for (int i = 0; i < 100; ++i) {
+        int64_t key_rand = thread->rand.Next() & (pot - 1);
+        GenerateKeyFromInt(key_rand, FLAGS_num, &key);
+        ++read;
+        auto status = db->Get(options, key, &value);
+        if (status.ok()) {
+          ++found;
+        } else if (!status.IsNotFound()) {
+          fprintf(stderr, "Get returned an error: %s\n",
+                  status.ToString().c_str());
+          abort();
+        }
+        if (key_rand >= FLAGS_num) {
+          ++nonexist;
+        }
+      }
+      if (thread->shared->read_rate_limiter.get() != nullptr) {
+        thread->shared->read_rate_limiter->Request(
+            100, Env::IO_HIGH, nullptr /* stats */, RateLimiter::OpType::kRead);
+      }
+
+      thread->stats.FinishedOps(nullptr, db, 100, kRead);
+    } while (!duration.Done(100));
+
+    char msg[100];
+    snprintf(msg, sizeof(msg), "(%" PRIu64 " of %" PRIu64 " found, "
+             "issued %" PRIu64 " non-exist keys)\n",
+             found, read, nonexist);
+
+    thread->stats.AddMessage(msg);
+
+    if (FLAGS_perf_level > rocksdb::PerfLevel::kDisable) {
+      thread->stats.AddMessage(std::string("PERF_CONTEXT:\n") +
+                               get_perf_context()->ToString());
+    }
+  }
+
+  int64_t GetRandomKey(Random64* rand) {
+    uint64_t rand_int = rand->Next();
+    int64_t key_rand;
+    if (read_random_exp_range_ == 0) {
+      key_rand = rand_int % FLAGS_num;
+    } else {
+      const uint64_t kBigInt = static_cast<uint64_t>(1U) << 62;
+      long double order = -static_cast<long double>(rand_int % kBigInt) /
+                          static_cast<long double>(kBigInt) *
+                          read_random_exp_range_;
+      long double exp_ran = std::exp(order);
+      uint64_t rand_num =
+          static_cast<int64_t>(exp_ran * static_cast<long double>(FLAGS_num));
+      // Map to a different number to avoid locality.
+      const uint64_t kBigPrime = 0x5bd1e995;
+      // Overflow is like %(2^64). Will have little impact of results.
+      key_rand = static_cast<int64_t>((rand_num * kBigPrime) % FLAGS_num);
+    }
+    return key_rand;
+  }
+
+  void ReadRandom(ThreadState* thread) {
+    int64_t read = 0;
+    int64_t found = 0;
+    int64_t bytes = 0;
+    ReadOptions options(FLAGS_verify_checksum, true);
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    PinnableSlice pinnable_val;
+
+    Duration duration(FLAGS_duration, reads_);
+    while (!duration.Done(1)) {
+      DBWithColumnFamilies* db_with_cfh = SelectDBWithCfh(thread);
+      // We use same key_rand as seed for key and column family so that we can
+      // deterministically find the cfh corresponding to a particular key, as it
+      // is done in DoWrite method.
+      int64_t key_rand = GetRandomKey(&thread->rand);
+      GenerateKeyFromInt(key_rand, FLAGS_num, &key);
+      read++;
+      Status s;
+      if (FLAGS_num_column_families > 1) {
+        s = db_with_cfh->db->Get(options, db_with_cfh->GetCfh(key_rand), key,
+                                 &pinnable_val);
+      } else {
+        pinnable_val.Reset();
+        s = db_with_cfh->db->Get(options,
+                                 db_with_cfh->db->DefaultColumnFamily(), key,
+                                 &pinnable_val);
+      }
+      if (s.ok()) {
+        found++;
+        bytes += key.size() + pinnable_val.size();
+      } else if (!s.IsNotFound()) {
+        fprintf(stderr, "Get returned an error: %s\n", s.ToString().c_str());
+        abort();
+      }
+
+      if (thread->shared->read_rate_limiter.get() != nullptr &&
+          read % 256 == 255) {
+        thread->shared->read_rate_limiter->Request(
+            256, Env::IO_HIGH, nullptr /* stats */, RateLimiter::OpType::kRead);
+      }
+
+      thread->stats.FinishedOps(db_with_cfh, db_with_cfh->db, 1, kRead);
+    }
+
+    char msg[100];
+    snprintf(msg, sizeof(msg), "(%" PRIu64 " of %" PRIu64 " found)\n",
+             found, read);
+
+    thread->stats.AddBytes(bytes);
+    thread->stats.AddMessage(msg);
+
+    if (FLAGS_perf_level > rocksdb::PerfLevel::kDisable) {
+      thread->stats.AddMessage(std::string("PERF_CONTEXT:\n") +
+                               get_perf_context()->ToString());
+    }
+  }
+
+  // Calls MultiGet over a list of keys from a random distribution.
+  // Returns the total number of keys found.
+  void MultiReadRandom(ThreadState* thread) {
+    int64_t read = 0;
+    int64_t num_multireads = 0;
+    int64_t found = 0;
+    ReadOptions options(FLAGS_verify_checksum, true);
+    std::vector<Slice> keys;
+    std::vector<std::unique_ptr<const char[]> > key_guards;
+    std::vector<std::string> values(entries_per_batch_);
+    while (static_cast<int64_t>(keys.size()) < entries_per_batch_) {
+      key_guards.push_back(std::unique_ptr<const char[]>());
+      keys.push_back(AllocateKey(&key_guards.back()));
+    }
+
+    Duration duration(FLAGS_duration, reads_);
+    while (!duration.Done(1)) {
+      DB* db = SelectDB(thread);
+      for (int64_t i = 0; i < entries_per_batch_; ++i) {
+        GenerateKeyFromInt(GetRandomKey(&thread->rand), FLAGS_num, &keys[i]);
+      }
+      std::vector<Status> statuses = db->MultiGet(options, keys, &values);
+      assert(static_cast<int64_t>(statuses.size()) == entries_per_batch_);
+
+      read += entries_per_batch_;
+      num_multireads++;
+      for (int64_t i = 0; i < entries_per_batch_; ++i) {
+        if (statuses[i].ok()) {
+          ++found;
+        } else if (!statuses[i].IsNotFound()) {
+          fprintf(stderr, "MultiGet returned an error: %s\n",
+                  statuses[i].ToString().c_str());
+          abort();
+        }
+      }
+      if (thread->shared->read_rate_limiter.get() != nullptr &&
+          num_multireads % 256 == 255) {
+        thread->shared->read_rate_limiter->Request(
+            256 * entries_per_batch_, Env::IO_HIGH, nullptr /* stats */,
+            RateLimiter::OpType::kRead);
+      }
+      thread->stats.FinishedOps(nullptr, db, entries_per_batch_, kRead);
+    }
+
+    char msg[100];
+    snprintf(msg, sizeof(msg), "(%" PRIu64 " of %" PRIu64 " found)",
+             found, read);
+    thread->stats.AddMessage(msg);
+  }
+
+  // THe reverse function of Pareto function
+  int64_t ParetoCdfInversion(double u, double theta, double k, double sigma) {
+    double ret;
+    if (k == 0.0) {
+      ret = theta - sigma * std::log(u);
+    } else {
+      ret = theta + sigma * (std::pow(u, -1 * k) - 1) / k;
+    }
+    return static_cast<int64_t>(ceil(ret));
+  }
+  // inversion of y=ax^b
+  int64_t PowerCdfInversion(double u, double a, double b) {
+    double ret;
+    ret = std::pow((u / a), (1 / b));
+    return static_cast<int64_t>(ceil(ret));
+  }
+
+  // Add the noice to the QPS
+  double AddNoise(double origin, double noise_ratio) {
+    if (noise_ratio < 0.0 || noise_ratio > 1.0) {
+      return origin;
+    }
+    int band_int = static_cast<int>(FLAGS_sine_a);
+    double delta = (rand() % band_int - band_int / 2) * noise_ratio;
+    if (origin + delta < 0) {
+      return origin;
+    } else {
+      return (origin + delta);
+    }
+  }
+
+  // decide the query type
+  // 0 Get, 1 Put, 2 Seek, 3 SeekForPrev, 4 Delete, 5 SingleDelete, 6 merge
+  class QueryDecider {
+   public:
+    std::vector<int> type_;
+    std::vector<double> ratio_;
+    int range_;
+
+    QueryDecider() {}
+    ~QueryDecider() {}
+
+    Status Initiate(std::vector<double> ratio_input) {
+      int range_max = 1000;
+      double sum = 0.0;
+      for (auto& ratio : ratio_input) {
+        sum += ratio;
+      }
+      range_ = 0;
+      for (auto& ratio : ratio_input) {
+        range_ += static_cast<int>(ceil(range_max * (ratio / sum)));
+        type_.push_back(range_);
+        ratio_.push_back(ratio / sum);
+      }
+      return Status::OK();
+    }
+
+    int GetType(int64_t rand_num) {
+      if (rand_num < 0) {
+        rand_num = rand_num * (-1);
+      }
+      assert(range_ != 0);
+      int pos = static_cast<int>(rand_num % range_);
+      for (int i = 0; i < static_cast<int>(type_.size()); i++) {
+        if (pos < type_[i]) {
+          return i;
+        }
+      }
+      return 0;
+    }
+  };
+
+  // The graph wokrload mixed with Get, Put, Iterator
+  void MixGraph(ThreadState* thread) {
+    int64_t read = 0;  // including single gets and Next of iterators
+    int64_t gets = 0;
+    int64_t puts = 0;
+    int64_t found = 0;
+    int64_t seek = 0;
+    int64_t seek_found = 0;
+    int64_t bytes = 0;
+    const int64_t default_value_max = 1 * 1024 * 1024;
+    int64_t value_max = default_value_max;
+    int64_t scan_len_max = FLAGS_mix_max_scan_len;
+    double write_rate = 1000000.0;
+    double read_rate = 1000000.0;
+    std::vector<double> ratio{FLAGS_mix_get_ratio, FLAGS_mix_put_ratio,
+                              FLAGS_mix_seek_ratio};
+    char value_buffer[default_value_max];
+    QueryDecider query;
+    RandomGenerator gen;
+    Status s;
+    if (value_max > FLAGS_mix_max_value_size) {
+      value_max = FLAGS_mix_max_value_size;
+    }
+
+    ReadOptions options(FLAGS_verify_checksum, true);
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    PinnableSlice pinnable_val;
+    query.Initiate(ratio);
+
+    // the limit of qps initiation
+    if (FLAGS_sine_a != 0 || FLAGS_sine_d != 0) {
+      thread->shared->read_rate_limiter.reset(NewGenericRateLimiter(
+          read_rate, 100000 /* refill_period_us */, 10 /* fairness */,
+          RateLimiter::Mode::kReadsOnly));
+      thread->shared->write_rate_limiter.reset(
+          NewGenericRateLimiter(write_rate));
+    }
+
+    Duration duration(FLAGS_duration, reads_);
+    while (!duration.Done(1)) {
+      DBWithColumnFamilies* db_with_cfh = SelectDBWithCfh(thread);
+      int64_t rand_v, key_rand, key_seed;
+      rand_v = GetRandomKey(&thread->rand) % FLAGS_num;
+      double u = static_cast<double>(rand_v) / FLAGS_num;
+      key_seed = PowerCdfInversion(u, FLAGS_key_dist_a, FLAGS_key_dist_b);
+      Random64 rand(key_seed);
+      key_rand = static_cast<int64_t>(rand.Next()) % FLAGS_num;
+      GenerateKeyFromInt(key_rand, FLAGS_num, &key);
+      int query_type = query.GetType(rand_v);
+
+      // change the qps
+      uint64_t now = FLAGS_env->NowMicros();
+      uint64_t usecs_since_last;
+      if (now > thread->stats.GetSineInterval()) {
+        usecs_since_last = now - thread->stats.GetSineInterval();
+      } else {
+        usecs_since_last = 0;
+      }
+
+      if (usecs_since_last >
+          (FLAGS_sine_mix_rate_interval_milliseconds * uint64_t{1000})) {
+        double usecs_since_start =
+            static_cast<double>(now - thread->stats.GetStart());
+        thread->stats.ResetSineInterval();
+        double mix_rate_with_noise = AddNoise(
+            SineRate(usecs_since_start / 1000000.0), FLAGS_sine_mix_rate_noise);
+        read_rate = mix_rate_with_noise * (query.ratio_[0] + query.ratio_[2]);
+        write_rate =
+            mix_rate_with_noise * query.ratio_[1] * FLAGS_mix_ave_kv_size;
+
+        thread->shared->write_rate_limiter.reset(
+            NewGenericRateLimiter(write_rate));
+        thread->shared->read_rate_limiter.reset(NewGenericRateLimiter(
+            read_rate,
+            FLAGS_sine_mix_rate_interval_milliseconds * uint64_t{1000}, 10,
+            RateLimiter::Mode::kReadsOnly));
+      }
+      // Start the query
+      if (query_type == 0) {
+        // the Get query
+        gets++;
+        read++;
+        if (FLAGS_num_column_families > 1) {
+          s = db_with_cfh->db->Get(options, db_with_cfh->GetCfh(key_rand), key,
+                                   &pinnable_val);
+        } else {
+          pinnable_val.Reset();
+          s = db_with_cfh->db->Get(options,
+                                   db_with_cfh->db->DefaultColumnFamily(), key,
+                                   &pinnable_val);
+        }
+
+        if (s.ok()) {
+          found++;
+          bytes += key.size() + pinnable_val.size();
+        } else if (!s.IsNotFound()) {
+          fprintf(stderr, "Get returned an error: %s\n", s.ToString().c_str());
+          abort();
+        }
+
+        if (thread->shared->read_rate_limiter.get() != nullptr &&
+            read % 256 == 255) {
+          thread->shared->read_rate_limiter->Request(
+              256, Env::IO_HIGH, nullptr /* stats */,
+              RateLimiter::OpType::kRead);
+        }
+        thread->stats.FinishedOps(db_with_cfh, db_with_cfh->db, 1, kRead);
+      } else if (query_type == 1) {
+        // the Put query
+        puts++;
+        int64_t value_size = ParetoCdfInversion(
+            u, FLAGS_value_theta, FLAGS_value_k, FLAGS_value_sigma);
+        if (value_size < 0) {
+          value_size = 10;
+        } else if (value_size > value_max) {
+          value_size = value_size % value_max;
+        }
+        s = db_with_cfh->db->Put(
+            write_options_, key,
+            gen.Generate(static_cast<unsigned int>(value_size)));
+        if (!s.ok()) {
+          fprintf(stderr, "put error: %s\n", s.ToString().c_str());
+          exit(1);
+        }
+
+        if (thread->shared->write_rate_limiter) {
+          thread->shared->write_rate_limiter->Request(
+              key.size() + value_size, Env::IO_HIGH, nullptr /*stats*/,
+              RateLimiter::OpType::kWrite);
+        }
+        thread->stats.FinishedOps(db_with_cfh, db_with_cfh->db, 1, kWrite);
+      } else if (query_type == 2) {
+        // Seek query
+        if (db_with_cfh->db != nullptr) {
+          Iterator* single_iter = nullptr;
+          single_iter = db_with_cfh->db->NewIterator(options);
+          if (single_iter != nullptr) {
+            single_iter->Seek(key);
+            seek++;
+            read++;
+            if (single_iter->Valid() && single_iter->key().compare(key) == 0) {
+              seek_found++;
+            }
+            int64_t scan_length =
+                ParetoCdfInversion(u, FLAGS_iter_theta, FLAGS_iter_k,
+                                   FLAGS_iter_sigma) %
+                scan_len_max;
+            for (int64_t j = 0; j < scan_length && single_iter->Valid(); j++) {
+              Slice value = single_iter->value();
+              memcpy(value_buffer, value.data(),
+                     std::min(value.size(), sizeof(value_buffer)));
+              bytes += single_iter->key().size() + single_iter->value().size();
+              single_iter->Next();
+              assert(single_iter->status().ok());
+            }
+          }
+          delete single_iter;
+        }
+        thread->stats.FinishedOps(db_with_cfh, db_with_cfh->db, 1, kSeek);
+      }
+    }
+    char msg[256];
+    snprintf(msg, sizeof(msg),
+             "( Gets:%" PRIu64 " Puts:%" PRIu64 " Seek:%" PRIu64 " of %" PRIu64
+             " in %" PRIu64 " found)\n",
+             gets, puts, seek, found, read);
+
+    thread->stats.AddBytes(bytes);
+    thread->stats.AddMessage(msg);
+
+    if (FLAGS_perf_level > rocksdb::PerfLevel::kDisable) {
+      thread->stats.AddMessage(std::string("PERF_CONTEXT:\n") +
+                               get_perf_context()->ToString());
+    }
+  }
+
+  void IteratorCreation(ThreadState* thread) {
+    Duration duration(FLAGS_duration, reads_);
+    ReadOptions options(FLAGS_verify_checksum, true);
+    while (!duration.Done(1)) {
+      DB* db = SelectDB(thread);
+      Iterator* iter = db->NewIterator(options);
+      delete iter;
+      thread->stats.FinishedOps(nullptr, db, 1, kOthers);
+    }
+  }
+
+  void IteratorCreationWhileWriting(ThreadState* thread) {
+    if (thread->tid > 0) {
+      IteratorCreation(thread);
+    } else {
+      BGWriter(thread, kWrite);
+    }
+  }
+
+  void SeekRandom(ThreadState* thread) {
+    int64_t read = 0;
+    int64_t found = 0;
+    int64_t bytes = 0;
+    ReadOptions options(FLAGS_verify_checksum, true);
+    options.tailing = FLAGS_use_tailing_iterator;
+
+    Iterator* single_iter = nullptr;
+    std::vector<Iterator*> multi_iters;
+    if (db_.db != nullptr) {
+      single_iter = db_.db->NewIterator(options);
+    } else {
+      for (const auto& db_with_cfh : multi_dbs_) {
+        multi_iters.push_back(db_with_cfh.db->NewIterator(options));
+      }
+    }
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+
+    std::unique_ptr<const char[]> upper_bound_key_guard;
+    Slice upper_bound = AllocateKey(&upper_bound_key_guard);
+    std::unique_ptr<const char[]> lower_bound_key_guard;
+    Slice lower_bound = AllocateKey(&lower_bound_key_guard);
+
+    Duration duration(FLAGS_duration, reads_);
+    char value_buffer[256];
+    while (!duration.Done(1)) {
+      int64_t seek_pos = thread->rand.Next() % FLAGS_num;
+      GenerateKeyFromInt((uint64_t)seek_pos, FLAGS_num, &key);
+      if (FLAGS_max_scan_distance != 0) {
+        if (FLAGS_reverse_iterator) {
+          GenerateKeyFromInt(
+              static_cast<uint64_t>(std::max(
+                  static_cast<int64_t>(0), seek_pos - FLAGS_max_scan_distance)),
+              FLAGS_num, &lower_bound);
+          options.iterate_lower_bound = &lower_bound;
+        } else {
+          GenerateKeyFromInt(
+              (uint64_t)std::min(FLAGS_num, seek_pos + FLAGS_max_scan_distance),
+              FLAGS_num, &upper_bound);
+          options.iterate_upper_bound = &upper_bound;
+        }
+      }
+
+      if (!FLAGS_use_tailing_iterator) {
+        if (db_.db != nullptr) {
+          delete single_iter;
+          single_iter = db_.db->NewIterator(options);
+        } else {
+          for (auto iter : multi_iters) {
+            delete iter;
+          }
+          multi_iters.clear();
+          for (const auto& db_with_cfh : multi_dbs_) {
+            multi_iters.push_back(db_with_cfh.db->NewIterator(options));
+          }
+        }
+      }
+      // Pick a Iterator to use
+      Iterator* iter_to_use = single_iter;
+      if (single_iter == nullptr) {
+        iter_to_use = multi_iters[thread->rand.Next() % multi_iters.size()];
+      }
+
+      iter_to_use->Seek(key);
+      read++;
+      if (iter_to_use->Valid() && iter_to_use->key().compare(key) == 0) {
+        found++;
+      }
+
+      for (int j = 0; j < FLAGS_seek_nexts && iter_to_use->Valid(); ++j) {
+        // Copy out iterator's value to make sure we read them.
+        Slice value = iter_to_use->value();
+        memcpy(value_buffer, value.data(),
+               std::min(value.size(), sizeof(value_buffer)));
+        bytes += iter_to_use->key().size() + iter_to_use->value().size();
+
+        if (!FLAGS_reverse_iterator) {
+          iter_to_use->Next();
+        } else {
+          iter_to_use->Prev();
+        }
+        assert(iter_to_use->status().ok());
+      }
+
+      if (thread->shared->read_rate_limiter.get() != nullptr &&
+          read % 256 == 255) {
+        thread->shared->read_rate_limiter->Request(
+            256, Env::IO_HIGH, nullptr /* stats */, RateLimiter::OpType::kRead);
+      }
+
+      thread->stats.FinishedOps(&db_, db_.db, 1, kSeek);
+    }
+    delete single_iter;
+    for (auto iter : multi_iters) {
+      delete iter;
+    }
+
+    char msg[100];
+    snprintf(msg, sizeof(msg), "(%" PRIu64 " of %" PRIu64 " found)\n",
+             found, read);
+    thread->stats.AddBytes(bytes);
+    thread->stats.AddMessage(msg);
+    if (FLAGS_perf_level > rocksdb::PerfLevel::kDisable) {
+      thread->stats.AddMessage(std::string("PERF_CONTEXT:\n") +
+                               get_perf_context()->ToString());
+    }
+  }
+
+  void SeekRandomWhileWriting(ThreadState* thread) {
+    if (thread->tid > 0) {
+      SeekRandom(thread);
+    } else {
+      BGWriter(thread, kWrite);
+    }
+  }
+
+  void SeekRandomWhileMerging(ThreadState* thread) {
+    if (thread->tid > 0) {
+      SeekRandom(thread);
+    } else {
+      BGWriter(thread, kMerge);
+    }
+  }
+
+  void DoDelete(ThreadState* thread, bool seq) {
+    WriteBatch batch;
+    Duration duration(seq ? 0 : FLAGS_duration, deletes_);
+    int64_t i = 0;
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+
+    while (!duration.Done(entries_per_batch_)) {
+      DB* db = SelectDB(thread);
+      batch.Clear();
+      for (int64_t j = 0; j < entries_per_batch_; ++j) {
+        const int64_t k = seq ? i + j : (thread->rand.Next() % FLAGS_num);
+        GenerateKeyFromInt(k, FLAGS_num, &key);
+        batch.Delete(key);
+      }
+      auto s = db->Write(write_options_, &batch);
+      thread->stats.FinishedOps(nullptr, db, entries_per_batch_, kDelete);
+      if (!s.ok()) {
+        fprintf(stderr, "del error: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+      i += entries_per_batch_;
+    }
+  }
+
+  void DeleteSeq(ThreadState* thread) {
+    DoDelete(thread, true);
+  }
+
+  void DeleteRandom(ThreadState* thread) {
+    DoDelete(thread, false);
+  }
+
+  void ReadWhileWriting(ThreadState* thread) {
+    if (thread->tid > 0) {
+      ReadRandom(thread);
+    } else {
+      BGWriter(thread, kWrite);
+    }
+  }
+
+  void ReadWhileMerging(ThreadState* thread) {
+    if (thread->tid > 0) {
+      ReadRandom(thread);
+    } else {
+      BGWriter(thread, kMerge);
+    }
+  }
+
+  void BGWriter(ThreadState* thread, enum OperationType write_merge) {
+    // Special thread that keeps writing until other threads are done.
+    RandomGenerator gen;
+    int64_t bytes = 0;
+
+    std::unique_ptr<RateLimiter> write_rate_limiter;
+    if (FLAGS_benchmark_write_rate_limit > 0) {
+      write_rate_limiter.reset(
+          NewGenericRateLimiter(FLAGS_benchmark_write_rate_limit));
+    }
+
+    // Don't merge stats from this thread with the readers.
+    thread->stats.SetExcludeFromMerge();
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    uint32_t written = 0;
+    bool hint_printed = false;
+
+    while (true) {
+      DB* db = SelectDB(thread);
+      {
+        MutexLock l(&thread->shared->mu);
+        if (FLAGS_finish_after_writes && written == writes_) {
+          fprintf(stderr, "Exiting the writer after %u writes...\n", written);
+          break;
+        }
+        if (thread->shared->num_done + 1 >= thread->shared->num_initialized) {
+          // Other threads have finished
+          if (FLAGS_finish_after_writes) {
+            // Wait for the writes to be finished
+            if (!hint_printed) {
+              fprintf(stderr, "Reads are finished. Have %d more writes to do\n",
+                      (int)writes_ - written);
+              hint_printed = true;
+            }
+          } else {
+            // Finish the write immediately
+            break;
+          }
+        }
+      }
+
+      GenerateKeyFromInt(thread->rand.Next() % FLAGS_num, FLAGS_num, &key);
+      Status s;
+
+      if (write_merge == kWrite) {
+        s = db->Put(write_options_, key, gen.Generate(value_size_));
+      } else {
+        s = db->Merge(write_options_, key, gen.Generate(value_size_));
+      }
+      written++;
+
+      if (!s.ok()) {
+        fprintf(stderr, "put or merge error: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+      bytes += key.size() + value_size_;
+      thread->stats.FinishedOps(&db_, db_.db, 1, kWrite);
+
+      if (FLAGS_benchmark_write_rate_limit > 0) {
+        write_rate_limiter->Request(
+            entries_per_batch_ * (value_size_ + key_size_), Env::IO_HIGH,
+            nullptr /* stats */, RateLimiter::OpType::kWrite);
+      }
+    }
+    thread->stats.AddBytes(bytes);
+  }
+
+  void ReadWhileScanning(ThreadState* thread) {
+    if (thread->tid > 0) {
+      ReadRandom(thread);
+    } else {
+      BGScan(thread);
+    }
+  }
+
+  void BGScan(ThreadState* thread) {
+    if (FLAGS_num_multi_db > 0) {
+      fprintf(stderr, "Not supporting multiple DBs.\n");
+      abort();
+    }
+    assert(db_.db != nullptr);
+    ReadOptions read_options;
+    Iterator* iter = db_.db->NewIterator(read_options);
+
+    fprintf(stderr, "num reads to do %" PRIu64 "\n", reads_);
+    Duration duration(FLAGS_duration, reads_);
+    uint64_t num_seek_to_first = 0;
+    uint64_t num_next = 0;
+    while (!duration.Done(1)) {
+      if (!iter->Valid()) {
+        iter->SeekToFirst();
+        num_seek_to_first++;
+      } else if (!iter->status().ok()) {
+        fprintf(stderr, "Iterator error: %s\n",
+                iter->status().ToString().c_str());
+        abort();
+      } else {
+        iter->Next();
+        num_next++;
+      }
+
+      thread->stats.FinishedOps(&db_, db_.db, 1, kSeek);
+    }
+    delete iter;
+  }
+
+  // Given a key K and value V, this puts (K+"0", V), (K+"1", V), (K+"2", V)
+  // in DB atomically i.e in a single batch. Also refer GetMany.
+  Status PutMany(DB* db, const WriteOptions& writeoptions, const Slice& key,
+                 const Slice& value) {
+    std::string suffixes[3] = {"2", "1", "0"};
+    std::string keys[3];
+
+    WriteBatch batch;
+    Status s;
+    for (int i = 0; i < 3; i++) {
+      keys[i] = key.ToString() + suffixes[i];
+      batch.Put(keys[i], value);
+    }
+
+    s = db->Write(writeoptions, &batch);
+    return s;
+  }
+
+
+  // Given a key K, this deletes (K+"0", V), (K+"1", V), (K+"2", V)
+  // in DB atomically i.e in a single batch. Also refer GetMany.
+  Status DeleteMany(DB* db, const WriteOptions& writeoptions,
+                    const Slice& key) {
+    std::string suffixes[3] = {"1", "2", "0"};
+    std::string keys[3];
+
+    WriteBatch batch;
+    Status s;
+    for (int i = 0; i < 3; i++) {
+      keys[i] = key.ToString() + suffixes[i];
+      batch.Delete(keys[i]);
+    }
+
+    s = db->Write(writeoptions, &batch);
+    return s;
+  }
+
+  // Given a key K and value V, this gets values for K+"0", K+"1" and K+"2"
+  // in the same snapshot, and verifies that all the values are identical.
+  // ASSUMES that PutMany was used to put (K, V) into the DB.
+  Status GetMany(DB* db, const ReadOptions& readoptions, const Slice& key,
+                 std::string* value) {
+    std::string suffixes[3] = {"0", "1", "2"};
+    std::string keys[3];
+    Slice key_slices[3];
+    std::string values[3];
+    ReadOptions readoptionscopy = readoptions;
+    readoptionscopy.snapshot = db->GetSnapshot();
+    Status s;
+    for (int i = 0; i < 3; i++) {
+      keys[i] = key.ToString() + suffixes[i];
+      key_slices[i] = keys[i];
+      s = db->Get(readoptionscopy, key_slices[i], value);
+      if (!s.ok() && !s.IsNotFound()) {
+        fprintf(stderr, "get error: %s\n", s.ToString().c_str());
+        values[i] = "";
+        // we continue after error rather than exiting so that we can
+        // find more errors if any
+      } else if (s.IsNotFound()) {
+        values[i] = "";
+      } else {
+        values[i] = *value;
+      }
+    }
+    db->ReleaseSnapshot(readoptionscopy.snapshot);
+
+    if ((values[0] != values[1]) || (values[1] != values[2])) {
+      fprintf(stderr, "inconsistent values for key %s: %s, %s, %s\n",
+              key.ToString().c_str(), values[0].c_str(), values[1].c_str(),
+              values[2].c_str());
+      // we continue after error rather than exiting so that we can
+      // find more errors if any
+    }
+
+    return s;
+  }
+
+  // Differs from readrandomwriterandom in the following ways:
+  // (a) Uses GetMany/PutMany to read/write key values. Refer to those funcs.
+  // (b) Does deletes as well (per FLAGS_deletepercent)
+  // (c) In order to achieve high % of 'found' during lookups, and to do
+  //     multiple writes (including puts and deletes) it uses upto
+  //     FLAGS_numdistinct distinct keys instead of FLAGS_num distinct keys.
+  // (d) Does not have a MultiGet option.
+  void RandomWithVerify(ThreadState* thread) {
+    ReadOptions options(FLAGS_verify_checksum, true);
+    RandomGenerator gen;
+    std::string value;
+    int64_t found = 0;
+    int get_weight = 0;
+    int put_weight = 0;
+    int delete_weight = 0;
+    int64_t gets_done = 0;
+    int64_t puts_done = 0;
+    int64_t deletes_done = 0;
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+
+    // the number of iterations is the larger of read_ or write_
+    for (int64_t i = 0; i < readwrites_; i++) {
+      DB* db = SelectDB(thread);
+      if (get_weight == 0 && put_weight == 0 && delete_weight == 0) {
+        // one batch completed, reinitialize for next batch
+        get_weight = FLAGS_readwritepercent;
+        delete_weight = FLAGS_deletepercent;
+        put_weight = 100 - get_weight - delete_weight;
+      }
+      GenerateKeyFromInt(thread->rand.Next() % FLAGS_numdistinct,
+          FLAGS_numdistinct, &key);
+      if (get_weight > 0) {
+        // do all the gets first
+        Status s = GetMany(db, options, key, &value);
+        if (!s.ok() && !s.IsNotFound()) {
+          fprintf(stderr, "getmany error: %s\n", s.ToString().c_str());
+          // we continue after error rather than exiting so that we can
+          // find more errors if any
+        } else if (!s.IsNotFound()) {
+          found++;
+        }
+        get_weight--;
+        gets_done++;
+        thread->stats.FinishedOps(&db_, db_.db, 1, kRead);
+      } else if (put_weight > 0) {
+        // then do all the corresponding number of puts
+        // for all the gets we have done earlier
+        Status s = PutMany(db, write_options_, key, gen.Generate(value_size_));
+        if (!s.ok()) {
+          fprintf(stderr, "putmany error: %s\n", s.ToString().c_str());
+          exit(1);
+        }
+        put_weight--;
+        puts_done++;
+        thread->stats.FinishedOps(&db_, db_.db, 1, kWrite);
+      } else if (delete_weight > 0) {
+        Status s = DeleteMany(db, write_options_, key);
+        if (!s.ok()) {
+          fprintf(stderr, "deletemany error: %s\n", s.ToString().c_str());
+          exit(1);
+        }
+        delete_weight--;
+        deletes_done++;
+        thread->stats.FinishedOps(&db_, db_.db, 1, kDelete);
+      }
+    }
+    char msg[128];
+    snprintf(msg, sizeof(msg),
+             "( get:%" PRIu64 " put:%" PRIu64 " del:%" PRIu64 " total:%" \
+             PRIu64 " found:%" PRIu64 ")",
+             gets_done, puts_done, deletes_done, readwrites_, found);
+    thread->stats.AddMessage(msg);
+  }
+
+  // This is different from ReadWhileWriting because it does not use
+  // an extra thread.
+  void ReadRandomWriteRandom(ThreadState* thread) {
+    ReadOptions options(FLAGS_verify_checksum, true);
+    RandomGenerator gen;
+    std::string value;
+    int64_t found = 0;
+    int get_weight = 0;
+    int put_weight = 0;
+    int64_t reads_done = 0;
+    int64_t writes_done = 0;
+    Duration duration(FLAGS_duration, readwrites_);
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+
+    // the number of iterations is the larger of read_ or write_
+    while (!duration.Done(1)) {
+      DB* db = SelectDB(thread);
+      GenerateKeyFromInt(thread->rand.Next() % FLAGS_num, FLAGS_num, &key);
+      if (get_weight == 0 && put_weight == 0) {
+        // one batch completed, reinitialize for next batch
+        get_weight = FLAGS_readwritepercent;
+        put_weight = 100 - get_weight;
+      }
+      if (get_weight > 0) {
+        // do all the gets first
+        Status s = db->Get(options, key, &value);
+        if (!s.ok() && !s.IsNotFound()) {
+          fprintf(stderr, "get error: %s\n", s.ToString().c_str());
+          // we continue after error rather than exiting so that we can
+          // find more errors if any
+        } else if (!s.IsNotFound()) {
+          found++;
+        }
+        get_weight--;
+        reads_done++;
+        thread->stats.FinishedOps(nullptr, db, 1, kRead);
+      } else  if (put_weight > 0) {
+        // then do all the corresponding number of puts
+        // for all the gets we have done earlier
+        Status s = db->Put(write_options_, key, gen.Generate(value_size_));
+        if (!s.ok()) {
+          fprintf(stderr, "put error: %s\n", s.ToString().c_str());
+          exit(1);
+        }
+        put_weight--;
+        writes_done++;
+        thread->stats.FinishedOps(nullptr, db, 1, kWrite);
+      }
+    }
+    char msg[100];
+    snprintf(msg, sizeof(msg), "( reads:%" PRIu64 " writes:%" PRIu64 \
+             " total:%" PRIu64 " found:%" PRIu64 ")",
+             reads_done, writes_done, readwrites_, found);
+    thread->stats.AddMessage(msg);
+  }
+
+  //
+  // Read-modify-write for random keys
+  void UpdateRandom(ThreadState* thread) {
+    ReadOptions options(FLAGS_verify_checksum, true);
+    RandomGenerator gen;
+    std::string value;
+    int64_t found = 0;
+    int64_t bytes = 0;
+    Duration duration(FLAGS_duration, readwrites_);
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    // the number of iterations is the larger of read_ or write_
+    while (!duration.Done(1)) {
+      DB* db = SelectDB(thread);
+      GenerateKeyFromInt(thread->rand.Next() % FLAGS_num, FLAGS_num, &key);
+
+      auto status = db->Get(options, key, &value);
+      if (status.ok()) {
+        ++found;
+        bytes += key.size() + value.size();
+      } else if (!status.IsNotFound()) {
+        fprintf(stderr, "Get returned an error: %s\n",
+                status.ToString().c_str());
+        abort();
+      }
+
+      if (thread->shared->write_rate_limiter) {
+        thread->shared->write_rate_limiter->Request(
+            key.size() + value_size_, Env::IO_HIGH, nullptr /*stats*/,
+            RateLimiter::OpType::kWrite);
+      }
+
+      Status s = db->Put(write_options_, key, gen.Generate(value_size_));
+      if (!s.ok()) {
+        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+      bytes += key.size() + value_size_;
+      thread->stats.FinishedOps(nullptr, db, 1, kUpdate);
+    }
+    char msg[100];
+    snprintf(msg, sizeof(msg),
+             "( updates:%" PRIu64 " found:%" PRIu64 ")", readwrites_, found);
+    thread->stats.AddBytes(bytes);
+    thread->stats.AddMessage(msg);
+  }
+
+  // Read-XOR-write for random keys. Xors the existing value with a randomly
+  // generated value, and stores the result. Assuming A in the array of bytes
+  // representing the existing value, we generate an array B of the same size,
+  // then compute C = A^B as C[i]=A[i]^B[i], and store C
+  void XORUpdateRandom(ThreadState* thread) {
+    ReadOptions options(FLAGS_verify_checksum, true);
+    RandomGenerator gen;
+    std::string existing_value;
+    int64_t found = 0;
+    Duration duration(FLAGS_duration, readwrites_);
+
+    BytesXOROperator xor_operator;
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    // the number of iterations is the larger of read_ or write_
+    while (!duration.Done(1)) {
+      DB* db = SelectDB(thread);
+      GenerateKeyFromInt(thread->rand.Next() % FLAGS_num, FLAGS_num, &key);
+
+      auto status = db->Get(options, key, &existing_value);
+      if (status.ok()) {
+        ++found;
+      } else if (!status.IsNotFound()) {
+        fprintf(stderr, "Get returned an error: %s\n",
+                status.ToString().c_str());
+        exit(1);
+      }
+
+      Slice value = gen.Generate(value_size_);
+      std::string new_value;
+
+      if (status.ok()) {
+        Slice existing_value_slice = Slice(existing_value);
+        xor_operator.XOR(&existing_value_slice, value, &new_value);
+      } else {
+        xor_operator.XOR(nullptr, value, &new_value);
+      }
+
+      Status s = db->Put(write_options_, key, Slice(new_value));
+      if (!s.ok()) {
+        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+      thread->stats.FinishedOps(nullptr, db, 1);
+    }
+    char msg[100];
+    snprintf(msg, sizeof(msg),
+             "( updates:%" PRIu64 " found:%" PRIu64 ")", readwrites_, found);
+    thread->stats.AddMessage(msg);
+  }
+
+  // Read-modify-write for random keys.
+  // Each operation causes the key grow by value_size (simulating an append).
+  // Generally used for benchmarking against merges of similar type
+  void AppendRandom(ThreadState* thread) {
+    ReadOptions options(FLAGS_verify_checksum, true);
+    RandomGenerator gen;
+    std::string value;
+    int64_t found = 0;
+    int64_t bytes = 0;
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    // The number of iterations is the larger of read_ or write_
+    Duration duration(FLAGS_duration, readwrites_);
+    while (!duration.Done(1)) {
+      DB* db = SelectDB(thread);
+      GenerateKeyFromInt(thread->rand.Next() % FLAGS_num, FLAGS_num, &key);
+
+      auto status = db->Get(options, key, &value);
+      if (status.ok()) {
+        ++found;
+        bytes += key.size() + value.size();
+      } else if (!status.IsNotFound()) {
+        fprintf(stderr, "Get returned an error: %s\n",
+                status.ToString().c_str());
+        abort();
+      } else {
+        // If not existing, then just assume an empty string of data
+        value.clear();
+      }
+
+      // Update the value (by appending data)
+      Slice operand = gen.Generate(value_size_);
+      if (value.size() > 0) {
+        // Use a delimiter to match the semantics for StringAppendOperator
+        value.append(1,',');
+      }
+      value.append(operand.data(), operand.size());
+
+      // Write back to the database
+      Status s = db->Put(write_options_, key, value);
+      if (!s.ok()) {
+        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+      bytes += key.size() + value.size();
+      thread->stats.FinishedOps(nullptr, db, 1, kUpdate);
+    }
+
+    char msg[100];
+    snprintf(msg, sizeof(msg), "( updates:%" PRIu64 " found:%" PRIu64 ")",
+            readwrites_, found);
+    thread->stats.AddBytes(bytes);
+    thread->stats.AddMessage(msg);
+  }
+
+  // Read-modify-write for random keys (using MergeOperator)
+  // The merge operator to use should be defined by FLAGS_merge_operator
+  // Adjust FLAGS_value_size so that the keys are reasonable for this operator
+  // Assumes that the merge operator is non-null (i.e.: is well-defined)
+  //
+  // For example, use FLAGS_merge_operator="uint64add" and FLAGS_value_size=8
+  // to simulate random additions over 64-bit integers using merge.
+  //
+  // The number of merges on the same key can be controlled by adjusting
+  // FLAGS_merge_keys.
+  void MergeRandom(ThreadState* thread) {
+    RandomGenerator gen;
+    int64_t bytes = 0;
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    // The number of iterations is the larger of read_ or write_
+    Duration duration(FLAGS_duration, readwrites_);
+    while (!duration.Done(1)) {
+      DBWithColumnFamilies* db_with_cfh = SelectDBWithCfh(thread);
+      int64_t key_rand = thread->rand.Next() % merge_keys_;
+      GenerateKeyFromInt(key_rand, merge_keys_, &key);
+
+      Status s;
+      if (FLAGS_num_column_families > 1) {
+        s = db_with_cfh->db->Merge(write_options_,
+                                   db_with_cfh->GetCfh(key_rand), key,
+                                   gen.Generate(value_size_));
+      } else {
+        s = db_with_cfh->db->Merge(write_options_,
+                                   db_with_cfh->db->DefaultColumnFamily(), key,
+                                   gen.Generate(value_size_));
+      }
+
+      if (!s.ok()) {
+        fprintf(stderr, "merge error: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+      bytes += key.size() + value_size_;
+      thread->stats.FinishedOps(nullptr, db_with_cfh->db, 1, kMerge);
+    }
+
+    // Print some statistics
+    char msg[100];
+    snprintf(msg, sizeof(msg), "( updates:%" PRIu64 ")", readwrites_);
+    thread->stats.AddBytes(bytes);
+    thread->stats.AddMessage(msg);
+  }
+
+  // Read and merge random keys. The amount of reads and merges are controlled
+  // by adjusting FLAGS_num and FLAGS_mergereadpercent. The number of distinct
+  // keys (and thus also the number of reads and merges on the same key) can be
+  // adjusted with FLAGS_merge_keys.
+  //
+  // As with MergeRandom, the merge operator to use should be defined by
+  // FLAGS_merge_operator.
+  void ReadRandomMergeRandom(ThreadState* thread) {
+    ReadOptions options(FLAGS_verify_checksum, true);
+    RandomGenerator gen;
+    std::string value;
+    int64_t num_hits = 0;
+    int64_t num_gets = 0;
+    int64_t num_merges = 0;
+    size_t max_length = 0;
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    // the number of iterations is the larger of read_ or write_
+    Duration duration(FLAGS_duration, readwrites_);
+    while (!duration.Done(1)) {
+      DB* db = SelectDB(thread);
+      GenerateKeyFromInt(thread->rand.Next() % merge_keys_, merge_keys_, &key);
+
+      bool do_merge = int(thread->rand.Next() % 100) < FLAGS_mergereadpercent;
+
+      if (do_merge) {
+        Status s = db->Merge(write_options_, key, gen.Generate(value_size_));
+        if (!s.ok()) {
+          fprintf(stderr, "merge error: %s\n", s.ToString().c_str());
+          exit(1);
+        }
+        num_merges++;
+        thread->stats.FinishedOps(nullptr, db, 1, kMerge);
+      } else {
+        Status s = db->Get(options, key, &value);
+        if (value.length() > max_length)
+          max_length = value.length();
+
+        if (!s.ok() && !s.IsNotFound()) {
+          fprintf(stderr, "get error: %s\n", s.ToString().c_str());
+          // we continue after error rather than exiting so that we can
+          // find more errors if any
+        } else if (!s.IsNotFound()) {
+          num_hits++;
+        }
+        num_gets++;
+        thread->stats.FinishedOps(nullptr, db, 1, kRead);
+      }
+    }
+
+    char msg[100];
+    snprintf(msg, sizeof(msg),
+             "(reads:%" PRIu64 " merges:%" PRIu64 " total:%" PRIu64
+             " hits:%" PRIu64 " maxlength:%" ROCKSDB_PRIszt ")",
+             num_gets, num_merges, readwrites_, num_hits, max_length);
+    thread->stats.AddMessage(msg);
+  }
+
+  void WriteSeqSeekSeq(ThreadState* thread) {
+    writes_ = FLAGS_num;
+    DoWrite(thread, SEQUENTIAL);
+    // exclude writes from the ops/sec calculation
+    thread->stats.Start(thread->tid);
+
+    DB* db = SelectDB(thread);
+    std::unique_ptr<Iterator> iter(
+      db->NewIterator(ReadOptions(FLAGS_verify_checksum, true)));
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    for (int64_t i = 0; i < FLAGS_num; ++i) {
+      GenerateKeyFromInt(i, FLAGS_num, &key);
+      iter->Seek(key);
+      assert(iter->Valid() && iter->key() == key);
+      thread->stats.FinishedOps(nullptr, db, 1, kSeek);
+
+      for (int j = 0; j < FLAGS_seek_nexts && i + 1 < FLAGS_num; ++j) {
+        if (!FLAGS_reverse_iterator) {
+          iter->Next();
+        } else {
+          iter->Prev();
+        }
+        GenerateKeyFromInt(++i, FLAGS_num, &key);
+        assert(iter->Valid() && iter->key() == key);
+        thread->stats.FinishedOps(nullptr, db, 1, kSeek);
+      }
+
+      iter->Seek(key);
+      assert(iter->Valid() && iter->key() == key);
+      thread->stats.FinishedOps(nullptr, db, 1, kSeek);
+    }
+  }
+
+#ifndef ROCKSDB_LITE
+  // This benchmark stress tests Transactions.  For a given --duration (or
+  // total number of --writes, a Transaction will perform a read-modify-write
+  // to increment the value of a key in each of N(--transaction-sets) sets of
+  // keys (where each set has --num keys).  If --threads is set, this will be
+  // done in parallel.
+  //
+  // To test transactions, use --transaction_db=true.  Not setting this
+  // parameter
+  // will run the same benchmark without transactions.
+  //
+  // RandomTransactionVerify() will then validate the correctness of the results
+  // by checking if the sum of all keys in each set is the same.
+  void RandomTransaction(ThreadState* thread) {
+    ReadOptions options(FLAGS_verify_checksum, true);
+    Duration duration(FLAGS_duration, readwrites_);
+    ReadOptions read_options(FLAGS_verify_checksum, true);
+    uint16_t num_prefix_ranges = static_cast<uint16_t>(FLAGS_transaction_sets);
+    uint64_t transactions_done = 0;
+
+    if (num_prefix_ranges == 0 || num_prefix_ranges > 9999) {
+      fprintf(stderr, "invalid value for transaction_sets\n");
+      abort();
+    }
+
+    TransactionOptions txn_options;
+    txn_options.lock_timeout = FLAGS_transaction_lock_timeout;
+    txn_options.set_snapshot = FLAGS_transaction_set_snapshot;
+
+    RandomTransactionInserter inserter(&thread->rand, write_options_,
+                                       read_options, FLAGS_num,
+                                       num_prefix_ranges);
+
+    if (FLAGS_num_multi_db > 1) {
+      fprintf(stderr,
+              "Cannot run RandomTransaction benchmark with "
+              "FLAGS_multi_db > 1.");
+      abort();
+    }
+
+    while (!duration.Done(1)) {
+      bool success;
+
+      // RandomTransactionInserter will attempt to insert a key for each
+      // # of FLAGS_transaction_sets
+      if (FLAGS_optimistic_transaction_db) {
+        success = inserter.OptimisticTransactionDBInsert(db_.opt_txn_db);
+      } else if (FLAGS_transaction_db) {
+        TransactionDB* txn_db = reinterpret_cast<TransactionDB*>(db_.db);
+        success = inserter.TransactionDBInsert(txn_db, txn_options);
+      } else {
+        success = inserter.DBInsert(db_.db);
+      }
+
+      if (!success) {
+        fprintf(stderr, "Unexpected error: %s\n",
+                inserter.GetLastStatus().ToString().c_str());
+        abort();
+      }
+
+      thread->stats.FinishedOps(nullptr, db_.db, 1, kOthers);
+      transactions_done++;
+    }
+
+    char msg[100];
+    if (FLAGS_optimistic_transaction_db || FLAGS_transaction_db) {
+      snprintf(msg, sizeof(msg),
+               "( transactions:%" PRIu64 " aborts:%" PRIu64 ")",
+               transactions_done, inserter.GetFailureCount());
+    } else {
+      snprintf(msg, sizeof(msg), "( batches:%" PRIu64 " )", transactions_done);
+    }
+    thread->stats.AddMessage(msg);
+
+    if (FLAGS_perf_level > rocksdb::PerfLevel::kDisable) {
+      thread->stats.AddMessage(std::string("PERF_CONTEXT:\n") +
+                               get_perf_context()->ToString());
+    }
+    thread->stats.AddBytes(static_cast<int64_t>(inserter.GetBytesInserted()));
+  }
+
+  // Verifies consistency of data after RandomTransaction() has been run.
+  // Since each iteration of RandomTransaction() incremented a key in each set
+  // by the same value, the sum of the keys in each set should be the same.
+  void RandomTransactionVerify() {
+    if (!FLAGS_transaction_db && !FLAGS_optimistic_transaction_db) {
+      // transactions not used, nothing to verify.
+      return;
+    }
+
+    Status s =
+        RandomTransactionInserter::Verify(db_.db,
+                            static_cast<uint16_t>(FLAGS_transaction_sets));
+
+    if (s.ok()) {
+      fprintf(stdout, "RandomTransactionVerify Success.\n");
+    } else {
+      fprintf(stdout, "RandomTransactionVerify FAILED!!\n");
+    }
+  }
+#endif  // ROCKSDB_LITE
+
+  // Writes and deletes random keys without overwriting keys.
+  //
+  // This benchmark is intended to partially replicate the behavior of MyRocks
+  // secondary indices: All data is stored in keys and updates happen by
+  // deleting the old version of the key and inserting the new version.
+  void RandomReplaceKeys(ThreadState* thread) {
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+    std::vector<uint32_t> counters(FLAGS_numdistinct, 0);
+    size_t max_counter = 50;
+    RandomGenerator gen;
+
+    Status s;
+    DB* db = SelectDB(thread);
+    for (int64_t i = 0; i < FLAGS_numdistinct; i++) {
+      GenerateKeyFromInt(i * max_counter, FLAGS_num, &key);
+      s = db->Put(write_options_, key, gen.Generate(value_size_));
+      if (!s.ok()) {
+        fprintf(stderr, "Operation failed: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+    }
+
+    db->GetSnapshot();
+
+    std::default_random_engine generator;
+    std::normal_distribution<double> distribution(FLAGS_numdistinct / 2.0,
+                                                  FLAGS_stddev);
+    Duration duration(FLAGS_duration, FLAGS_num);
+    while (!duration.Done(1)) {
+      int64_t rnd_id = static_cast<int64_t>(distribution(generator));
+      int64_t key_id = std::max(std::min(FLAGS_numdistinct - 1, rnd_id),
+                                static_cast<int64_t>(0));
+      GenerateKeyFromInt(key_id * max_counter + counters[key_id], FLAGS_num,
+                         &key);
+      s = FLAGS_use_single_deletes ? db->SingleDelete(write_options_, key)
+                                   : db->Delete(write_options_, key);
+      if (s.ok()) {
+        counters[key_id] = (counters[key_id] + 1) % max_counter;
+        GenerateKeyFromInt(key_id * max_counter + counters[key_id], FLAGS_num,
+                           &key);
+        s = db->Put(write_options_, key, Slice());
+      }
+
+      if (!s.ok()) {
+        fprintf(stderr, "Operation failed: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+
+      thread->stats.FinishedOps(nullptr, db, 1, kOthers);
+    }
+
+    char msg[200];
+    snprintf(msg, sizeof(msg),
+             "use single deletes: %d, "
+             "standard deviation: %lf\n",
+             FLAGS_use_single_deletes, FLAGS_stddev);
+    thread->stats.AddMessage(msg);
+  }
+
+  void TimeSeriesReadOrDelete(ThreadState* thread, bool do_deletion) {
+    ReadOptions options(FLAGS_verify_checksum, true);
+    int64_t read = 0;
+    int64_t found = 0;
+    int64_t bytes = 0;
+
+    Iterator* iter = nullptr;
+    // Only work on single database
+    assert(db_.db != nullptr);
+    iter = db_.db->NewIterator(options);
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+
+    char value_buffer[256];
+    while (true) {
+      {
+        MutexLock l(&thread->shared->mu);
+        if (thread->shared->num_done >= 1) {
+          // Write thread have finished
+          break;
+        }
+      }
+      if (!FLAGS_use_tailing_iterator) {
+        delete iter;
+        iter = db_.db->NewIterator(options);
+      }
+      // Pick a Iterator to use
+
+      int64_t key_id = thread->rand.Next() % FLAGS_key_id_range;
+      GenerateKeyFromInt(key_id, FLAGS_num, &key);
+      // Reset last 8 bytes to 0
+      char* start = const_cast<char*>(key.data());
+      start += key.size() - 8;
+      memset(start, 0, 8);
+      ++read;
+
+      bool key_found = false;
+      // Seek the prefix
+      for (iter->Seek(key); iter->Valid() && iter->key().starts_with(key);
+           iter->Next()) {
+        key_found = true;
+        // Copy out iterator's value to make sure we read them.
+        if (do_deletion) {
+          bytes += iter->key().size();
+          if (KeyExpired(timestamp_emulator_.get(), iter->key())) {
+            thread->stats.FinishedOps(&db_, db_.db, 1, kDelete);
+            db_.db->Delete(write_options_, iter->key());
+          } else {
+            break;
+          }
+        } else {
+          bytes += iter->key().size() + iter->value().size();
+          thread->stats.FinishedOps(&db_, db_.db, 1, kRead);
+          Slice value = iter->value();
+          memcpy(value_buffer, value.data(),
+                 std::min(value.size(), sizeof(value_buffer)));
+
+          assert(iter->status().ok());
+        }
+      }
+      found += key_found;
+
+      if (thread->shared->read_rate_limiter.get() != nullptr) {
+        thread->shared->read_rate_limiter->Request(
+            1, Env::IO_HIGH, nullptr /* stats */, RateLimiter::OpType::kRead);
+      }
+    }
+    delete iter;
+
+    char msg[100];
+    snprintf(msg, sizeof(msg), "(%" PRIu64 " of %" PRIu64 " found)", found,
+             read);
+    thread->stats.AddBytes(bytes);
+    thread->stats.AddMessage(msg);
+    if (FLAGS_perf_level > rocksdb::PerfLevel::kDisable) {
+      thread->stats.AddMessage(std::string("PERF_CONTEXT:\n") +
+                               get_perf_context()->ToString());
+    }
+  }
+
+  void TimeSeriesWrite(ThreadState* thread) {
+    // Special thread that keeps writing until other threads are done.
+    RandomGenerator gen;
+    int64_t bytes = 0;
+
+    // Don't merge stats from this thread with the readers.
+    thread->stats.SetExcludeFromMerge();
+
+    std::unique_ptr<RateLimiter> write_rate_limiter;
+    if (FLAGS_benchmark_write_rate_limit > 0) {
+      write_rate_limiter.reset(
+          NewGenericRateLimiter(FLAGS_benchmark_write_rate_limit));
+    }
+
+    std::unique_ptr<const char[]> key_guard;
+    Slice key = AllocateKey(&key_guard);
+
+    Duration duration(FLAGS_duration, writes_);
+    while (!duration.Done(1)) {
+      DB* db = SelectDB(thread);
+
+      uint64_t key_id = thread->rand.Next() % FLAGS_key_id_range;
+      // Write key id
+      GenerateKeyFromInt(key_id, FLAGS_num, &key);
+      // Write timestamp
+
+      char* start = const_cast<char*>(key.data());
+      char* pos = start + 8;
+      int bytes_to_fill =
+          std::min(key_size_ - static_cast<int>(pos - start), 8);
+      uint64_t timestamp_value = timestamp_emulator_->Get();
+      if (port::kLittleEndian) {
+        for (int i = 0; i < bytes_to_fill; ++i) {
+          pos[i] = (timestamp_value >> ((bytes_to_fill - i - 1) << 3)) & 0xFF;
+        }
+      } else {
+        memcpy(pos, static_cast<void*>(&timestamp_value), bytes_to_fill);
+      }
+
+      timestamp_emulator_->Inc();
+
+      Status s;
+
+      s = db->Put(write_options_, key, gen.Generate(value_size_));
+
+      if (!s.ok()) {
+        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
+        exit(1);
+      }
+      bytes = key.size() + value_size_;
+      thread->stats.FinishedOps(&db_, db_.db, 1, kWrite);
+      thread->stats.AddBytes(bytes);
+
+      if (FLAGS_benchmark_write_rate_limit > 0) {
+        write_rate_limiter->Request(
+            entries_per_batch_ * (value_size_ + key_size_), Env::IO_HIGH,
+            nullptr /* stats */, RateLimiter::OpType::kWrite);
+      }
+    }
+  }
+
+  void TimeSeries(ThreadState* thread) {
+    if (thread->tid > 0) {
+      bool do_deletion = FLAGS_expire_style == "delete" &&
+                         thread->tid <= FLAGS_num_deletion_threads;
+      TimeSeriesReadOrDelete(thread, do_deletion);
+    } else {
+      TimeSeriesWrite(thread);
+      thread->stats.Stop();
+      thread->stats.Report("timeseries write");
+    }
+  }
+
+  void Compact(ThreadState* thread) {
+    DB* db = SelectDB(thread);
+    CompactRangeOptions cro;
+    cro.bottommost_level_compaction = BottommostLevelCompaction::kForce;
+    db->CompactRange(cro, nullptr, nullptr);
+  }
+
+  void CompactAll() {
+    if (db_.db != nullptr) {
+      db_.db->CompactRange(CompactRangeOptions(), nullptr, nullptr);
+    }
+    for (const auto& db_with_cfh : multi_dbs_) {
+      db_with_cfh.db->CompactRange(CompactRangeOptions(), nullptr, nullptr);
+    }
+  }
+
+  void ResetStats() {
+    if (db_.db != nullptr) {
+      db_.db->ResetStats();
+    }
+    for (const auto& db_with_cfh : multi_dbs_) {
+      db_with_cfh.db->ResetStats();
+    }
+  }
+
+  void PrintStats(const char* key) {
+    if (db_.db != nullptr) {
+      PrintStats(db_.db, key, false);
+    }
+    for (const auto& db_with_cfh : multi_dbs_) {
+      PrintStats(db_with_cfh.db, key, true);
+    }
+  }
+
+  void PrintStats(DB* db, const char* key, bool print_header = false) {
+    if (print_header) {
+      fprintf(stdout, "\n==== DB: %s ===\n", db->GetName().c_str());
+    }
+    std::string stats;
+    if (!db->GetProperty(key, &stats)) {
+      stats = "(failed)";
+    }
+    fprintf(stdout, "\n%s\n", stats.c_str());
+  }
+
+  void Replay(ThreadState* thread) {
+    if (db_.db != nullptr) {
+      Replay(thread, &db_);
+    }
+  }
+
+  void Replay(ThreadState* /*thread*/, DBWithColumnFamilies* db_with_cfh) {
+    Status s;
+    std::unique_ptr<TraceReader> trace_reader;
+    s = NewFileTraceReader(FLAGS_env, EnvOptions(), FLAGS_trace_file,
+                           &trace_reader);
+    if (!s.ok()) {
+      fprintf(
+          stderr,
+          "Encountered an error creating a TraceReader from the trace file. "
+          "Error: %s\n",
+          s.ToString().c_str());
+      exit(1);
+    }
+    Replayer replayer(db_with_cfh->db, db_with_cfh->cfh,
+                      std::move(trace_reader));
+    s = replayer.Replay();
+    if (s.ok()) {
+      fprintf(stdout, "Replay started from trace_file: %s\n",
+              FLAGS_trace_file.c_str());
+    } else {
+      fprintf(stderr, "Starting replay failed. Error: %s\n",
+              s.ToString().c_str());
+    }
+  }
+};
+
+int db_bench_tool(int argc, char** argv) {
+  rocksdb::port::InstallStackTraceHandler();
+  static bool initialized = false;
+  if (!initialized) {
+    SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) +
+                    " [OPTIONS]...");
+    initialized = true;
+  }
+  ParseCommandLineFlags(&argc, &argv, true);
+  FLAGS_compaction_style_e = (rocksdb::CompactionStyle) FLAGS_compaction_style;
+#ifndef ROCKSDB_LITE
+  if (FLAGS_statistics && !FLAGS_statistics_string.empty()) {
+    fprintf(stderr,
+            "Cannot provide both --statistics and --statistics_string.\n");
+    exit(1);
+  }
+  if (!FLAGS_statistics_string.empty()) {
+    std::unique_ptr<Statistics> custom_stats_guard;
+    dbstats.reset(NewCustomObject<Statistics>(FLAGS_statistics_string,
+                                              &custom_stats_guard));
+    custom_stats_guard.release();
+    if (dbstats == nullptr) {
+      fprintf(stderr, "No Statistics registered matching string: %s\n",
+              FLAGS_statistics_string.c_str());
+      exit(1);
+    }
+  }
+#endif  // ROCKSDB_LITE
+  if (FLAGS_statistics) {
+    dbstats = rocksdb::CreateDBStatistics();
+  }
+  if (dbstats) {
+    dbstats->set_stats_level(static_cast<StatsLevel>(FLAGS_stats_level));
+  }
+  FLAGS_compaction_pri_e = (rocksdb::CompactionPri)FLAGS_compaction_pri;
+
+  std::vector<std::string> fanout = rocksdb::StringSplit(
+      FLAGS_max_bytes_for_level_multiplier_additional, ',');
+  for (size_t j = 0; j < fanout.size(); j++) {
+    FLAGS_max_bytes_for_level_multiplier_additional_v.push_back(
+#ifndef CYGWIN
+        std::stoi(fanout[j]));
+#else
+        stoi(fanout[j]));
+#endif
+  }
+
+  FLAGS_compression_type_e =
+    StringToCompressionType(FLAGS_compression_type.c_str());
+
+#ifndef ROCKSDB_LITE
+  std::unique_ptr<Env> custom_env_guard;
+  if (!FLAGS_hdfs.empty() && !FLAGS_env_uri.empty()) {
+    fprintf(stderr, "Cannot provide both --hdfs and --env_uri.\n");
+    exit(1);
+  } else if (!FLAGS_env_uri.empty()) {
+    FLAGS_env = NewCustomObject<Env>(FLAGS_env_uri, &custom_env_guard);
+    if (FLAGS_env == nullptr) {
+      fprintf(stderr, "No Env registered for URI: %s\n", FLAGS_env_uri.c_str());
+      exit(1);
+    }
+  }
+#endif  // ROCKSDB_LITE
+  if (FLAGS_use_existing_keys && !FLAGS_use_existing_db) {
+    fprintf(stderr,
+            "`-use_existing_db` must be true for `-use_existing_keys` to be "
+            "settable\n");
+    exit(1);
+  }
+
+  if (!FLAGS_hdfs.empty()) {
+    FLAGS_env  = new rocksdb::HdfsEnv(FLAGS_hdfs);
+  }
+
+  if (!strcasecmp(FLAGS_compaction_fadvice.c_str(), "NONE"))
+    FLAGS_compaction_fadvice_e = rocksdb::Options::NONE;
+  else if (!strcasecmp(FLAGS_compaction_fadvice.c_str(), "NORMAL"))
+    FLAGS_compaction_fadvice_e = rocksdb::Options::NORMAL;
+  else if (!strcasecmp(FLAGS_compaction_fadvice.c_str(), "SEQUENTIAL"))
+    FLAGS_compaction_fadvice_e = rocksdb::Options::SEQUENTIAL;
+  else if (!strcasecmp(FLAGS_compaction_fadvice.c_str(), "WILLNEED"))
+    FLAGS_compaction_fadvice_e = rocksdb::Options::WILLNEED;
+  else {
+    fprintf(stdout, "Unknown compaction fadvice:%s\n",
+            FLAGS_compaction_fadvice.c_str());
+  }
+
+  FLAGS_rep_factory = StringToRepFactory(FLAGS_memtablerep.c_str());
+
+  // Note options sanitization may increase thread pool sizes according to
+  // max_background_flushes/max_background_compactions/max_background_jobs
+  FLAGS_env->SetBackgroundThreads(FLAGS_num_high_pri_threads,
+                                  rocksdb::Env::Priority::HIGH);
+  FLAGS_env->SetBackgroundThreads(FLAGS_num_bottom_pri_threads,
+                                  rocksdb::Env::Priority::BOTTOM);
+  FLAGS_env->SetBackgroundThreads(FLAGS_num_low_pri_threads,
+                                  rocksdb::Env::Priority::LOW);
+
+  // Choose a location for the test database if none given with --db=<path>
+  if (FLAGS_db.empty()) {
+    std::string default_db_path;
+    rocksdb::Env::Default()->GetTestDirectory(&default_db_path);
+    default_db_path += "/dbbench";
+    FLAGS_db = default_db_path;
+  }
+
+  if (FLAGS_stats_interval_seconds > 0) {
+    // When both are set then FLAGS_stats_interval determines the frequency
+    // at which the timer is checked for FLAGS_stats_interval_seconds
+    FLAGS_stats_interval = 1000;
+  }
+
+  rocksdb::Benchmark benchmark;
+  benchmark.Run();
+
+#ifndef ROCKSDB_LITE
+  if (FLAGS_print_malloc_stats) {
+    std::string stats_string;
+    rocksdb::DumpMallocStats(&stats_string);
+    fprintf(stdout, "Malloc stats:\n%s\n", stats_string.c_str());
+  }
+#endif  // ROCKSDB_LITE
+
+  return 0;
+}
+}  // namespace rocksdb
+#endif
diff --git a/src/rocksdb/tools/db_bench_tool_test.cc b/src/rocksdb/tools/db_bench_tool_test.cc
new file mode 100644
index 00000000..1b19de5f
--- /dev/null
+++ b/src/rocksdb/tools/db_bench_tool_test.cc
@@ -0,0 +1,319 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include "rocksdb/db_bench_tool.h"
+#include "options/options_parser.h"
+#include "rocksdb/utilities/options_util.h"
+#include "util/random.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+
+#ifdef GFLAGS
+#include "util/gflags_compat.h"
+
+namespace rocksdb {
+namespace {
+static const int kMaxArgCount = 100;
+static const size_t kArgBufferSize = 100000;
+}  // namespace
+
+class DBBenchTest : public testing::Test {
+ public:
+  DBBenchTest() : rnd_(0xFB) {
+    test_path_ = test::PerThreadDBPath("db_bench_test");
+    Env::Default()->CreateDir(test_path_);
+    db_path_ = test_path_ + "/db";
+    wal_path_ = test_path_ + "/wal";
+  }
+
+  ~DBBenchTest() {
+    //  DestroyDB(db_path_, Options());
+  }
+
+  void ResetArgs() {
+    argc_ = 0;
+    cursor_ = 0;
+    memset(arg_buffer_, 0, kArgBufferSize);
+  }
+
+  void AppendArgs(const std::vector<std::string>& args) {
+    for (const auto& arg : args) {
+      ASSERT_LE(cursor_ + arg.size() + 1, kArgBufferSize);
+      ASSERT_LE(argc_ + 1, kMaxArgCount);
+      snprintf(arg_buffer_ + cursor_, arg.size() + 1, "%s", arg.c_str());
+
+      argv_[argc_++] = arg_buffer_ + cursor_;
+      cursor_ += arg.size() + 1;
+    }
+  }
+
+  void RunDbBench(const std::string& options_file_name) {
+    AppendArgs({"./db_bench", "--benchmarks=fillseq", "--use_existing_db=0",
+                "--num=1000",
+                std::string(std::string("--db=") + db_path_).c_str(),
+                std::string(std::string("--wal_dir=") + wal_path_).c_str(),
+                std::string(std::string("--options_file=") + options_file_name)
+                    .c_str()});
+    ASSERT_EQ(0, db_bench_tool(argc(), argv()));
+  }
+
+  void VerifyOptions(const Options& opt) {
+    DBOptions loaded_db_opts;
+    std::vector<ColumnFamilyDescriptor> cf_descs;
+    ASSERT_OK(LoadLatestOptions(db_path_, Env::Default(), &loaded_db_opts,
+                                &cf_descs));
+
+    ASSERT_OK(
+        RocksDBOptionsParser::VerifyDBOptions(DBOptions(opt), loaded_db_opts));
+    ASSERT_OK(RocksDBOptionsParser::VerifyCFOptions(ColumnFamilyOptions(opt),
+                                                    cf_descs[0].options));
+
+    // check with the default rocksdb options and expect failure
+    ASSERT_NOK(
+        RocksDBOptionsParser::VerifyDBOptions(DBOptions(), loaded_db_opts));
+    ASSERT_NOK(RocksDBOptionsParser::VerifyCFOptions(ColumnFamilyOptions(),
+                                                     cf_descs[0].options));
+  }
+
+  char** argv() { return argv_; }
+
+  int argc() { return argc_; }
+
+  std::string db_path_;
+  std::string test_path_;
+  std::string wal_path_;
+
+  char arg_buffer_[kArgBufferSize];
+  char* argv_[kMaxArgCount];
+  int argc_ = 0;
+  int cursor_ = 0;
+  Random rnd_;
+};
+
+namespace {}  // namespace
+
+TEST_F(DBBenchTest, OptionsFile) {
+  const std::string kOptionsFileName = test_path_ + "/OPTIONS_test";
+
+  Options opt;
+  opt.create_if_missing = true;
+  opt.max_open_files = 256;
+  opt.max_background_compactions = 10;
+  opt.arena_block_size = 8388608;
+  ASSERT_OK(PersistRocksDBOptions(DBOptions(opt), {"default"},
+                                  {ColumnFamilyOptions(opt)}, kOptionsFileName,
+                                  Env::Default()));
+
+  // override the following options as db_bench will not take these
+  // options from the options file
+  opt.wal_dir = wal_path_;
+
+  RunDbBench(kOptionsFileName);
+
+  VerifyOptions(opt);
+}
+
+TEST_F(DBBenchTest, OptionsFileUniversal) {
+  const std::string kOptionsFileName = test_path_ + "/OPTIONS_test";
+
+  Options opt;
+  opt.compaction_style = kCompactionStyleUniversal;
+  opt.num_levels = 1;
+  opt.create_if_missing = true;
+  opt.max_open_files = 256;
+  opt.max_background_compactions = 10;
+  opt.arena_block_size = 8388608;
+  ASSERT_OK(PersistRocksDBOptions(DBOptions(opt), {"default"},
+                                  {ColumnFamilyOptions(opt)}, kOptionsFileName,
+                                  Env::Default()));
+
+  // override the following options as db_bench will not take these
+  // options from the options file
+  opt.wal_dir = wal_path_;
+
+  RunDbBench(kOptionsFileName);
+
+  VerifyOptions(opt);
+}
+
+TEST_F(DBBenchTest, OptionsFileMultiLevelUniversal) {
+  const std::string kOptionsFileName = test_path_ + "/OPTIONS_test";
+
+  Options opt;
+  opt.compaction_style = kCompactionStyleUniversal;
+  opt.num_levels = 12;
+  opt.create_if_missing = true;
+  opt.max_open_files = 256;
+  opt.max_background_compactions = 10;
+  opt.arena_block_size = 8388608;
+  ASSERT_OK(PersistRocksDBOptions(DBOptions(opt), {"default"},
+                                  {ColumnFamilyOptions(opt)}, kOptionsFileName,
+                                  Env::Default()));
+
+  // override the following options as db_bench will not take these
+  // options from the options file
+  opt.wal_dir = wal_path_;
+
+  RunDbBench(kOptionsFileName);
+
+  VerifyOptions(opt);
+}
+
+const std::string options_file_content = R"OPTIONS_FILE(
+[Version]
+  rocksdb_version=4.3.1
+  options_file_version=1.1
+
+[DBOptions]
+  wal_bytes_per_sync=1048576
+  delete_obsolete_files_period_micros=0
+  WAL_ttl_seconds=0
+  WAL_size_limit_MB=0
+  db_write_buffer_size=0
+  max_subcompactions=1
+  table_cache_numshardbits=4
+  max_open_files=-1
+  max_file_opening_threads=10
+  max_background_compactions=5
+  use_fsync=false
+  use_adaptive_mutex=false
+  max_total_wal_size=18446744073709551615
+  compaction_readahead_size=0
+  new_table_reader_for_compaction_inputs=false
+  keep_log_file_num=10
+  skip_stats_update_on_db_open=false
+  max_manifest_file_size=18446744073709551615
+  db_log_dir=
+  skip_log_error_on_recovery=false
+  writable_file_max_buffer_size=1048576
+  paranoid_checks=true
+  is_fd_close_on_exec=true
+  bytes_per_sync=1048576
+  enable_thread_tracking=true
+  recycle_log_file_num=0
+  create_missing_column_families=false
+  log_file_time_to_roll=0
+  max_background_flushes=1
+  create_if_missing=true
+  error_if_exists=false
+  delayed_write_rate=1048576
+  manifest_preallocation_size=4194304
+  allow_mmap_reads=false
+  allow_mmap_writes=false
+  use_direct_reads=false
+  use_direct_io_for_flush_and_compaction=false
+  stats_dump_period_sec=600
+  allow_fallocate=true
+  max_log_file_size=83886080
+  random_access_max_buffer_size=1048576
+  advise_random_on_open=true
+
+
+[CFOptions "default"]
+  compaction_filter_factory=nullptr
+  table_factory=BlockBasedTable
+  prefix_extractor=nullptr
+  comparator=leveldb.BytewiseComparator
+  compression_per_level=
+  max_bytes_for_level_base=104857600
+  bloom_locality=0
+  target_file_size_base=10485760
+  memtable_huge_page_size=0
+  max_successive_merges=1000
+  max_sequential_skip_in_iterations=8
+  arena_block_size=52428800
+  target_file_size_multiplier=1
+  source_compaction_factor=1
+  min_write_buffer_number_to_merge=1
+  max_write_buffer_number=2
+  write_buffer_size=419430400
+  max_grandparent_overlap_factor=10
+  max_bytes_for_level_multiplier=10
+  memtable_factory=SkipListFactory
+  compression=kSnappyCompression
+  min_partial_merge_operands=2
+  level0_stop_writes_trigger=100
+  num_levels=1
+  level0_slowdown_writes_trigger=50
+  level0_file_num_compaction_trigger=10
+  expanded_compaction_factor=25
+  soft_rate_limit=0.000000
+  max_write_buffer_number_to_maintain=0
+  verify_checksums_in_compaction=true
+  merge_operator=nullptr
+  memtable_prefix_bloom_bits=0
+  memtable_whole_key_filtering=true
+  paranoid_file_checks=false
+  inplace_update_num_locks=10000
+  optimize_filters_for_hits=false
+  level_compaction_dynamic_level_bytes=false
+  inplace_update_support=false
+  compaction_style=kCompactionStyleUniversal
+  memtable_prefix_bloom_probes=6
+  purge_redundant_kvs_while_flush=true
+  filter_deletes=false
+  hard_pending_compaction_bytes_limit=0
+  disable_auto_compactions=false
+  compaction_measure_io_stats=false
+
+[TableOptions/BlockBasedTable "default"]
+  format_version=0
+  skip_table_builder_flush=false
+  cache_index_and_filter_blocks=false
+  flush_block_policy_factory=FlushBlockBySizePolicyFactory
+  hash_index_allow_collision=true
+  index_type=kBinarySearch
+  whole_key_filtering=true
+  checksum=kCRC32c
+  no_block_cache=false
+  block_size=32768
+  block_size_deviation=10
+  block_restart_interval=16
+  filter_policy=rocksdb.BuiltinBloomFilter
+)OPTIONS_FILE";
+
+TEST_F(DBBenchTest, OptionsFileFromFile) {
+  const std::string kOptionsFileName = test_path_ + "/OPTIONS_flash";
+  std::unique_ptr<WritableFile> writable;
+  ASSERT_OK(Env::Default()->NewWritableFile(kOptionsFileName, &writable,
+                                            EnvOptions()));
+  ASSERT_OK(writable->Append(options_file_content));
+  ASSERT_OK(writable->Close());
+
+  DBOptions db_opt;
+  std::vector<ColumnFamilyDescriptor> cf_descs;
+  ASSERT_OK(LoadOptionsFromFile(kOptionsFileName, Env::Default(), &db_opt,
+                                &cf_descs));
+  Options opt(db_opt, cf_descs[0].options);
+
+  opt.create_if_missing = true;
+
+  // override the following options as db_bench will not take these
+  // options from the options file
+  opt.wal_dir = wal_path_;
+
+  RunDbBench(kOptionsFileName);
+
+  VerifyOptions(opt);
+}
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  google::ParseCommandLineFlags(&argc, &argv, true);
+  return RUN_ALL_TESTS();
+}
+
+#else
+
+int main(int argc, char** argv) {
+  printf("Skip db_bench_tool_test as the required library GFLAG is missing.");
+}
+#endif  // #ifdef GFLAGS
diff --git a/src/rocksdb/tools/db_crashtest.py b/src/rocksdb/tools/db_crashtest.py
new file mode 100644
index 00000000..dbabb2b4
--- /dev/null
+++ b/src/rocksdb/tools/db_crashtest.py
@@ -0,0 +1,405 @@
+#! /usr/bin/env python
+import os
+import sys
+import time
+import random
+import tempfile
+import subprocess
+import shutil
+import argparse
+
+# params overwrite priority:
+#   for default:
+#       default_params < {blackbox,whitebox}_default_params < args
+#   for simple:
+#       default_params < {blackbox,whitebox}_default_params <
+#       simple_default_params <
+#       {blackbox,whitebox}_simple_default_params < args
+#   for enable_atomic_flush:
+#       default_params < {blackbox,whitebox}_default_params <
+#       atomic_flush_params < args
+
+expected_values_file = tempfile.NamedTemporaryFile()
+
+default_params = {
+    "acquire_snapshot_one_in": 10000,
+    "block_size": 16384,
+    "cache_size": 1048576,
+    "checkpoint_one_in": 1000000,
+    "compression_type": "snappy",
+    "compression_max_dict_bytes": lambda: 16384 * random.randint(0, 1),
+    "compression_zstd_max_train_bytes": lambda: 65536 * random.randint(0, 1),
+    "clear_column_family_one_in": 0,
+    "compact_files_one_in": 1000000,
+    "compact_range_one_in": 1000000,
+    "delpercent": 4,
+    "delrangepercent": 1,
+    "destroy_db_initially": 0,
+    "enable_pipelined_write": lambda: random.randint(0, 1),
+    "expected_values_path": expected_values_file.name,
+    "flush_one_in": 1000000,
+    "max_background_compactions": 20,
+    "max_bytes_for_level_base": 10485760,
+    "max_key": 100000000,
+    "max_write_buffer_number": 3,
+    "mmap_read": lambda: random.randint(0, 1),
+    "nooverwritepercent": 1,
+    "open_files": 500000,
+    "prefixpercent": 5,
+    "progress_reports": 0,
+    "readpercent": 45,
+    "recycle_log_file_num": lambda: random.randint(0, 1),
+    "reopen": 20,
+    "snapshot_hold_ops": 100000,
+    "subcompactions": lambda: random.randint(1, 4),
+    "target_file_size_base": 2097152,
+    "target_file_size_multiplier": 2,
+    "use_direct_reads": lambda: random.randint(0, 1),
+    "use_direct_io_for_flush_and_compaction": lambda: random.randint(0, 1),
+    "use_full_merge_v1": lambda: random.randint(0, 1),
+    "use_merge": lambda: random.randint(0, 1),
+    "verify_checksum": 1,
+    "write_buffer_size": 4 * 1024 * 1024,
+    "writepercent": 35,
+    "format_version": lambda: random.randint(2, 4),
+    "index_block_restart_interval": lambda: random.choice(range(1, 16)),
+}
+
+_TEST_DIR_ENV_VAR = 'TEST_TMPDIR'
+
+
+def get_dbname(test_name):
+    test_tmpdir = os.environ.get(_TEST_DIR_ENV_VAR)
+    if test_tmpdir is None or test_tmpdir == "":
+        dbname = tempfile.mkdtemp(prefix='rocksdb_crashtest_' + test_name)
+    else:
+        dbname = test_tmpdir + "/rocksdb_crashtest_" + test_name
+        shutil.rmtree(dbname, True)
+        os.mkdir(dbname)
+    return dbname
+
+
+def is_direct_io_supported(dbname):
+    with tempfile.NamedTemporaryFile(dir=dbname) as f:
+        try:
+            os.open(f.name, os.O_DIRECT)
+        except:
+            return False
+        return True
+
+
+blackbox_default_params = {
+    # total time for this script to test db_stress
+    "duration": 6000,
+    # time for one db_stress instance to run
+    "interval": 120,
+    # since we will be killing anyway, use large value for ops_per_thread
+    "ops_per_thread": 100000000,
+    "set_options_one_in": 10000,
+    "test_batches_snapshots": 1,
+}
+
+whitebox_default_params = {
+    "duration": 10000,
+    "log2_keys_per_lock": 10,
+    "ops_per_thread": 200000,
+    "random_kill_odd": 888887,
+    "test_batches_snapshots": lambda: random.randint(0, 1),
+}
+
+simple_default_params = {
+    "allow_concurrent_memtable_write": lambda: random.randint(0, 1),
+    "column_families": 1,
+    "max_background_compactions": 1,
+    "max_bytes_for_level_base": 67108864,
+    "memtablerep": "skip_list",
+    "prefixpercent": 25,
+    "readpercent": 25,
+    "target_file_size_base": 16777216,
+    "target_file_size_multiplier": 1,
+    "test_batches_snapshots": 0,
+    "write_buffer_size": 32 * 1024 * 1024,
+}
+
+blackbox_simple_default_params = {
+    "open_files": -1,
+    "set_options_one_in": 0,
+}
+
+whitebox_simple_default_params = {}
+
+atomic_flush_params = {
+    "disable_wal": 1,
+    "reopen": 0,
+    "test_atomic_flush": 1,
+    # use small value for write_buffer_size so that RocksDB triggers flush
+    # more frequently
+    "write_buffer_size": 1024 * 1024,
+}
+
+
+def finalize_and_sanitize(src_params):
+    dest_params = dict([(k,  v() if callable(v) else v)
+                        for (k, v) in src_params.items()])
+    if dest_params.get("compression_type") != "zstd" or \
+            dest_params.get("compression_max_dict_bytes") == 0:
+        dest_params["compression_zstd_max_train_bytes"] = 0
+    if dest_params.get("allow_concurrent_memtable_write", 1) == 1:
+        dest_params["memtablerep"] = "skip_list"
+    if dest_params["mmap_read"] == 1 or not is_direct_io_supported(
+            dest_params["db"]):
+        dest_params["use_direct_io_for_flush_and_compaction"] = 0
+        dest_params["use_direct_reads"] = 0
+    if dest_params.get("test_batches_snapshots") == 1:
+        dest_params["delpercent"] += dest_params["delrangepercent"]
+        dest_params["delrangepercent"] = 0
+    return dest_params
+
+
+def gen_cmd_params(args):
+    params = {}
+
+    params.update(default_params)
+    if args.test_type == 'blackbox':
+        params.update(blackbox_default_params)
+    if args.test_type == 'whitebox':
+        params.update(whitebox_default_params)
+    if args.simple:
+        params.update(simple_default_params)
+        if args.test_type == 'blackbox':
+            params.update(blackbox_simple_default_params)
+        if args.test_type == 'whitebox':
+            params.update(whitebox_simple_default_params)
+    if args.enable_atomic_flush:
+        params.update(atomic_flush_params)
+
+    for k, v in vars(args).items():
+        if v is not None:
+            params[k] = v
+    return params
+
+
+def gen_cmd(params, unknown_params):
+    cmd = ['./db_stress'] + [
+        '--{0}={1}'.format(k, v)
+        for k, v in finalize_and_sanitize(params).items()
+        if k not in set(['test_type', 'simple', 'duration', 'interval',
+                         'random_kill_odd', 'enable_atomic_flush'])
+        and v is not None] + unknown_params
+    return cmd
+
+
+# This script runs and kills db_stress multiple times. It checks consistency
+# in case of unsafe crashes in RocksDB.
+def blackbox_crash_main(args, unknown_args):
+    cmd_params = gen_cmd_params(args)
+    dbname = get_dbname('blackbox')
+    exit_time = time.time() + cmd_params['duration']
+
+    print("Running blackbox-crash-test with \n"
+          + "interval_between_crash=" + str(cmd_params['interval']) + "\n"
+          + "total-duration=" + str(cmd_params['duration']) + "\n")
+
+    while time.time() < exit_time:
+        run_had_errors = False
+        killtime = time.time() + cmd_params['interval']
+
+        cmd = gen_cmd(dict(
+            cmd_params.items() +
+            {'db': dbname}.items()), unknown_args)
+
+        child = subprocess.Popen(cmd, stderr=subprocess.PIPE)
+        print("Running db_stress with pid=%d: %s\n\n"
+              % (child.pid, ' '.join(cmd)))
+
+        stop_early = False
+        while time.time() < killtime:
+            if child.poll() is not None:
+                print("WARNING: db_stress ended before kill: exitcode=%d\n"
+                      % child.returncode)
+                stop_early = True
+                break
+            time.sleep(1)
+
+        if not stop_early:
+            if child.poll() is not None:
+                print("WARNING: db_stress ended before kill: exitcode=%d\n"
+                      % child.returncode)
+            else:
+                child.kill()
+                print("KILLED %d\n" % child.pid)
+                time.sleep(1)  # time to stabilize after a kill
+
+        while True:
+            line = child.stderr.readline().strip()
+            if line == '':
+                break
+            elif not line.startswith('WARNING'):
+                run_had_errors = True
+                print('stderr has error message:')
+                print('***' + line + '***')
+
+        if run_had_errors:
+            sys.exit(2)
+
+        time.sleep(1)  # time to stabilize before the next run
+
+    # we need to clean up after ourselves -- only do this on test success
+    shutil.rmtree(dbname, True)
+
+
+# This python script runs db_stress multiple times. Some runs with
+# kill_random_test that causes rocksdb to crash at various points in code.
+def whitebox_crash_main(args, unknown_args):
+    cmd_params = gen_cmd_params(args)
+    dbname = get_dbname('whitebox')
+
+    cur_time = time.time()
+    exit_time = cur_time + cmd_params['duration']
+    half_time = cur_time + cmd_params['duration'] / 2
+
+    print("Running whitebox-crash-test with \n"
+          + "total-duration=" + str(cmd_params['duration']) + "\n")
+
+    total_check_mode = 4
+    check_mode = 0
+    kill_random_test = cmd_params['random_kill_odd']
+    kill_mode = 0
+
+    while time.time() < exit_time:
+        if check_mode == 0:
+            additional_opts = {
+                # use large ops per thread since we will kill it anyway
+                "ops_per_thread": 100 * cmd_params['ops_per_thread'],
+            }
+            # run with kill_random_test, with three modes.
+            # Mode 0 covers all kill points. Mode 1 covers less kill points but
+            # increases change of triggering them. Mode 2 covers even less
+            # frequent kill points and further increases triggering change.
+            if kill_mode == 0:
+                additional_opts.update({
+                    "kill_random_test": kill_random_test,
+                })
+            elif kill_mode == 1:
+                additional_opts.update({
+                    "kill_random_test": (kill_random_test / 10 + 1),
+                    "kill_prefix_blacklist": "WritableFileWriter::Append,"
+                    + "WritableFileWriter::WriteBuffered",
+                })
+            elif kill_mode == 2:
+                # TODO: May need to adjust random odds if kill_random_test
+                # is too small.
+                additional_opts.update({
+                    "kill_random_test": (kill_random_test / 5000 + 1),
+                    "kill_prefix_blacklist": "WritableFileWriter::Append,"
+                    "WritableFileWriter::WriteBuffered,"
+                    "PosixMmapFile::Allocate,WritableFileWriter::Flush",
+                })
+            # Run kill mode 0, 1 and 2 by turn.
+            kill_mode = (kill_mode + 1) % 3
+        elif check_mode == 1:
+            # normal run with universal compaction mode
+            additional_opts = {
+                "kill_random_test": None,
+                "ops_per_thread": cmd_params['ops_per_thread'],
+                "compaction_style": 1,
+            }
+        elif check_mode == 2:
+            # normal run with FIFO compaction mode
+            # ops_per_thread is divided by 5 because FIFO compaction
+            # style is quite a bit slower on reads with lot of files
+            additional_opts = {
+                "kill_random_test": None,
+                "ops_per_thread": cmd_params['ops_per_thread'] / 5,
+                "compaction_style": 2,
+            }
+        else:
+            # normal run
+            additional_opts = {
+                "kill_random_test": None,
+                "ops_per_thread": cmd_params['ops_per_thread'],
+            }
+
+        cmd = gen_cmd(dict(cmd_params.items() + additional_opts.items()
+                           + {'db': dbname}.items()), unknown_args)
+
+        print "Running:" + ' '.join(cmd) + "\n"  # noqa: E999 T25377293 Grandfathered in
+
+        popen = subprocess.Popen(cmd, stdout=subprocess.PIPE,
+                                 stderr=subprocess.STDOUT)
+        stdoutdata, stderrdata = popen.communicate()
+        retncode = popen.returncode
+        msg = ("check_mode={0}, kill option={1}, exitcode={2}\n".format(
+               check_mode, additional_opts['kill_random_test'], retncode))
+        print msg
+        print stdoutdata
+
+        expected = False
+        if additional_opts['kill_random_test'] is None and (retncode == 0):
+            # we expect zero retncode if no kill option
+            expected = True
+        elif additional_opts['kill_random_test'] is not None and retncode < 0:
+            # we expect negative retncode if kill option was given
+            expected = True
+
+        if not expected:
+            print "TEST FAILED. See kill option and exit code above!!!\n"
+            sys.exit(1)
+
+        stdoutdata = stdoutdata.lower()
+        errorcount = (stdoutdata.count('error') -
+                      stdoutdata.count('got errors 0 times'))
+        print "#times error occurred in output is " + str(errorcount) + "\n"
+
+        if (errorcount > 0):
+            print "TEST FAILED. Output has 'error'!!!\n"
+            sys.exit(2)
+        if (stdoutdata.find('fail') >= 0):
+            print "TEST FAILED. Output has 'fail'!!!\n"
+            sys.exit(2)
+
+        # First half of the duration, keep doing kill test. For the next half,
+        # try different modes.
+        if time.time() > half_time:
+            # we need to clean up after ourselves -- only do this on test
+            # success
+            shutil.rmtree(dbname, True)
+            os.mkdir(dbname)
+            cmd_params.pop('expected_values_path', None)
+            check_mode = (check_mode + 1) % total_check_mode
+
+        time.sleep(1)  # time to stabilize after a kill
+
+
+def main():
+    parser = argparse.ArgumentParser(description="This script runs and kills \
+        db_stress multiple times")
+    parser.add_argument("test_type", choices=["blackbox", "whitebox"])
+    parser.add_argument("--simple", action="store_true")
+    parser.add_argument("--enable_atomic_flush", action='store_true')
+
+    all_params = dict(default_params.items()
+                      + blackbox_default_params.items()
+                      + whitebox_default_params.items()
+                      + simple_default_params.items()
+                      + blackbox_simple_default_params.items()
+                      + whitebox_simple_default_params.items())
+
+    for k, v in all_params.items():
+        parser.add_argument("--" + k, type=type(v() if callable(v) else v))
+    # unknown_args are passed directly to db_stress
+    args, unknown_args = parser.parse_known_args()
+
+    test_tmpdir = os.environ.get(_TEST_DIR_ENV_VAR)
+    if test_tmpdir is not None and not os.path.isdir(test_tmpdir):
+        print('%s env var is set to a non-existent directory: %s' %
+                (_TEST_DIR_ENV_VAR, test_tmpdir))
+        sys.exit(1)
+
+    if args.test_type == 'blackbox':
+        blackbox_crash_main(args, unknown_args)
+    if args.test_type == 'whitebox':
+        whitebox_crash_main(args, unknown_args)
+
+if __name__ == '__main__':
+    main()
diff --git a/src/rocksdb/tools/db_repl_stress.cc b/src/rocksdb/tools/db_repl_stress.cc
new file mode 100644
index 00000000..c640b594
--- /dev/null
+++ b/src/rocksdb/tools/db_repl_stress.cc
@@ -0,0 +1,159 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#ifndef ROCKSDB_LITE
+#ifndef GFLAGS
+#include <cstdio>
+int main() {
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+  return 1;
+}
+#else
+
+#include <atomic>
+#include <cstdio>
+
+#include "db/write_batch_internal.h"
+#include "rocksdb/db.h"
+#include "rocksdb/types.h"
+#include "util/gflags_compat.h"
+#include "util/testutil.h"
+
+// Run a thread to perform Put's.
+// Another thread uses GetUpdatesSince API to keep getting the updates.
+// options :
+// --num_inserts = the num of inserts the first thread should perform.
+// --wal_ttl = the wal ttl for the run.
+
+using namespace rocksdb;
+
+using GFLAGS_NAMESPACE::ParseCommandLineFlags;
+using GFLAGS_NAMESPACE::SetUsageMessage;
+
+struct DataPumpThread {
+  size_t no_records;
+  DB* db;  // Assumption DB is Open'ed already.
+};
+
+static std::string RandomString(Random* rnd, int len) {
+  std::string r;
+  test::RandomString(rnd, len, &r);
+  return r;
+}
+
+static void DataPumpThreadBody(void* arg) {
+  DataPumpThread* t = reinterpret_cast<DataPumpThread*>(arg);
+  DB* db = t->db;
+  Random rnd(301);
+  size_t i = 0;
+  while (i++ < t->no_records) {
+    if (!db->Put(WriteOptions(), Slice(RandomString(&rnd, 500)),
+                 Slice(RandomString(&rnd, 500)))
+             .ok()) {
+      fprintf(stderr, "Error in put\n");
+      exit(1);
+    }
+  }
+}
+
+struct ReplicationThread {
+  std::atomic<bool> stop;
+  DB* db;
+  volatile size_t no_read;
+};
+
+static void ReplicationThreadBody(void* arg) {
+  ReplicationThread* t = reinterpret_cast<ReplicationThread*>(arg);
+  DB* db = t->db;
+  std::unique_ptr<TransactionLogIterator> iter;
+  SequenceNumber currentSeqNum = 1;
+  while (!t->stop.load(std::memory_order_acquire)) {
+    iter.reset();
+    Status s;
+    while (!db->GetUpdatesSince(currentSeqNum, &iter).ok()) {
+      if (t->stop.load(std::memory_order_acquire)) {
+        return;
+      }
+    }
+    fprintf(stderr, "Refreshing iterator\n");
+    for (; iter->Valid(); iter->Next(), t->no_read++, currentSeqNum++) {
+      BatchResult res = iter->GetBatch();
+      if (res.sequence != currentSeqNum) {
+        fprintf(stderr, "Missed a seq no. b/w %ld and %ld\n",
+                (long)currentSeqNum, (long)res.sequence);
+        exit(1);
+      }
+    }
+  }
+}
+
+DEFINE_uint64(num_inserts, 1000,
+              "the num of inserts the first thread should"
+              " perform.");
+DEFINE_uint64(wal_ttl_seconds, 1000, "the wal ttl for the run(in seconds)");
+DEFINE_uint64(wal_size_limit_MB, 10,
+              "the wal size limit for the run"
+              "(in MB)");
+
+int main(int argc, const char** argv) {
+  SetUsageMessage(
+      std::string("\nUSAGE:\n") + std::string(argv[0]) +
+      " --num_inserts=<num_inserts> --wal_ttl_seconds=<WAL_ttl_seconds>" +
+      " --wal_size_limit_MB=<WAL_size_limit_MB>");
+  ParseCommandLineFlags(&argc, const_cast<char***>(&argv), true);
+
+  Env* env = Env::Default();
+  std::string default_db_path;
+  env->GetTestDirectory(&default_db_path);
+  default_db_path += "db_repl_stress";
+  Options options;
+  options.create_if_missing = true;
+  options.WAL_ttl_seconds = FLAGS_wal_ttl_seconds;
+  options.WAL_size_limit_MB = FLAGS_wal_size_limit_MB;
+  DB* db;
+  DestroyDB(default_db_path, options);
+
+  Status s = DB::Open(options, default_db_path, &db);
+
+  if (!s.ok()) {
+    fprintf(stderr, "Could not open DB due to %s\n", s.ToString().c_str());
+    exit(1);
+  }
+
+  DataPumpThread dataPump;
+  dataPump.no_records = FLAGS_num_inserts;
+  dataPump.db = db;
+  env->StartThread(DataPumpThreadBody, &dataPump);
+
+  ReplicationThread replThread;
+  replThread.db = db;
+  replThread.no_read = 0;
+  replThread.stop.store(false, std::memory_order_release);
+
+  env->StartThread(ReplicationThreadBody, &replThread);
+  while (replThread.no_read < FLAGS_num_inserts)
+    ;
+  replThread.stop.store(true, std::memory_order_release);
+  if (replThread.no_read < dataPump.no_records) {
+    // no. read should be => than inserted.
+    fprintf(stderr,
+            "No. of Record's written and read not same\nRead : %" ROCKSDB_PRIszt
+            " Written : %" ROCKSDB_PRIszt "\n",
+            replThread.no_read, dataPump.no_records);
+    exit(1);
+  }
+  fprintf(stderr, "Successful!\n");
+  exit(0);
+}
+
+#endif  // GFLAGS
+
+#else  // ROCKSDB_LITE
+#include <stdio.h>
+int main(int /*argc*/, char** /*argv*/) {
+  fprintf(stderr, "Not supported in lite mode.\n");
+  return 1;
+}
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/db_sanity_test.cc b/src/rocksdb/tools/db_sanity_test.cc
new file mode 100644
index 00000000..b40fe613
--- /dev/null
+++ b/src/rocksdb/tools/db_sanity_test.cc
@@ -0,0 +1,297 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#include <cstdio>
+#include <cstdlib>
+#include <vector>
+#include <memory>
+
+#include "rocksdb/db.h"
+#include "rocksdb/options.h"
+#include "rocksdb/env.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/status.h"
+#include "rocksdb/comparator.h"
+#include "rocksdb/table.h"
+#include "rocksdb/slice_transform.h"
+#include "rocksdb/filter_policy.h"
+#include "port/port.h"
+#include "util/string_util.h"
+
+namespace rocksdb {
+
+class SanityTest {
+ public:
+  explicit SanityTest(const std::string& path)
+      : env_(Env::Default()), path_(path) {
+    env_->CreateDirIfMissing(path);
+  }
+  virtual ~SanityTest() {}
+
+  virtual std::string Name() const = 0;
+  virtual Options GetOptions() const = 0;
+
+  Status Create() {
+    Options options = GetOptions();
+    options.create_if_missing = true;
+    std::string dbname = path_ + Name();
+    DestroyDB(dbname, options);
+    DB* db = nullptr;
+    Status s = DB::Open(options, dbname, &db);
+    std::unique_ptr<DB> db_guard(db);
+    if (!s.ok()) {
+      return s;
+    }
+    for (int i = 0; i < 1000000; ++i) {
+      std::string k = "key" + ToString(i);
+      std::string v = "value" + ToString(i);
+      s = db->Put(WriteOptions(), Slice(k), Slice(v));
+      if (!s.ok()) {
+        return s;
+      }
+    }
+    return db->Flush(FlushOptions());
+  }
+  Status Verify() {
+    DB* db = nullptr;
+    std::string dbname = path_ + Name();
+    Status s = DB::Open(GetOptions(), dbname, &db);
+    std::unique_ptr<DB> db_guard(db);
+    if (!s.ok()) {
+      return s;
+    }
+    for (int i = 0; i < 1000000; ++i) {
+      std::string k = "key" + ToString(i);
+      std::string v = "value" + ToString(i);
+      std::string result;
+      s = db->Get(ReadOptions(), Slice(k), &result);
+      if (!s.ok()) {
+        return s;
+      }
+      if (result != v) {
+        return Status::Corruption("Unexpected value for key " + k);
+      }
+    }
+    return Status::OK();
+  }
+
+ private:
+  Env* env_;
+  std::string const path_;
+};
+
+class SanityTestBasic : public SanityTest {
+ public:
+  explicit SanityTestBasic(const std::string& path) : SanityTest(path) {}
+  virtual Options GetOptions() const override {
+    Options options;
+    options.create_if_missing = true;
+    return options;
+  }
+  virtual std::string Name() const override { return "Basic"; }
+};
+
+class SanityTestSpecialComparator : public SanityTest {
+ public:
+  explicit SanityTestSpecialComparator(const std::string& path)
+      : SanityTest(path) {
+    options_.comparator = new NewComparator();
+  }
+  ~SanityTestSpecialComparator() { delete options_.comparator; }
+  virtual Options GetOptions() const override { return options_; }
+  virtual std::string Name() const override { return "SpecialComparator"; }
+
+ private:
+  class NewComparator : public Comparator {
+   public:
+    virtual const char* Name() const override {
+      return "rocksdb.NewComparator";
+    }
+    virtual int Compare(const Slice& a, const Slice& b) const override {
+      return BytewiseComparator()->Compare(a, b);
+    }
+    virtual void FindShortestSeparator(std::string* s,
+                                       const Slice& l) const override {
+      BytewiseComparator()->FindShortestSeparator(s, l);
+    }
+    virtual void FindShortSuccessor(std::string* key) const override {
+      BytewiseComparator()->FindShortSuccessor(key);
+    }
+  };
+  Options options_;
+};
+
+class SanityTestZlibCompression : public SanityTest {
+ public:
+  explicit SanityTestZlibCompression(const std::string& path)
+      : SanityTest(path) {
+    options_.compression = kZlibCompression;
+  }
+  virtual Options GetOptions() const override { return options_; }
+  virtual std::string Name() const override { return "ZlibCompression"; }
+
+ private:
+  Options options_;
+};
+
+class SanityTestZlibCompressionVersion2 : public SanityTest {
+ public:
+  explicit SanityTestZlibCompressionVersion2(const std::string& path)
+      : SanityTest(path) {
+    options_.compression = kZlibCompression;
+    BlockBasedTableOptions table_options;
+#if ROCKSDB_MAJOR > 3 || (ROCKSDB_MAJOR == 3 && ROCKSDB_MINOR >= 10)
+    table_options.format_version = 2;
+#endif
+    options_.table_factory.reset(NewBlockBasedTableFactory(table_options));
+  }
+  virtual Options GetOptions() const override { return options_; }
+  virtual std::string Name() const override {
+    return "ZlibCompressionVersion2";
+  }
+
+ private:
+  Options options_;
+};
+
+class SanityTestLZ4Compression : public SanityTest {
+ public:
+  explicit SanityTestLZ4Compression(const std::string& path)
+      : SanityTest(path) {
+    options_.compression = kLZ4Compression;
+  }
+  virtual Options GetOptions() const override { return options_; }
+  virtual std::string Name() const override { return "LZ4Compression"; }
+
+ private:
+  Options options_;
+};
+
+class SanityTestLZ4HCCompression : public SanityTest {
+ public:
+  explicit SanityTestLZ4HCCompression(const std::string& path)
+      : SanityTest(path) {
+    options_.compression = kLZ4HCCompression;
+  }
+  virtual Options GetOptions() const override { return options_; }
+  virtual std::string Name() const override { return "LZ4HCCompression"; }
+
+ private:
+  Options options_;
+};
+
+class SanityTestZSTDCompression : public SanityTest {
+ public:
+  explicit SanityTestZSTDCompression(const std::string& path)
+      : SanityTest(path) {
+    options_.compression = kZSTD;
+  }
+  virtual Options GetOptions() const override { return options_; }
+  virtual std::string Name() const override { return "ZSTDCompression"; }
+
+ private:
+  Options options_;
+};
+
+#ifndef ROCKSDB_LITE
+class SanityTestPlainTableFactory : public SanityTest {
+ public:
+  explicit SanityTestPlainTableFactory(const std::string& path)
+      : SanityTest(path) {
+    options_.table_factory.reset(NewPlainTableFactory());
+    options_.prefix_extractor.reset(NewFixedPrefixTransform(2));
+    options_.allow_mmap_reads = true;
+  }
+  ~SanityTestPlainTableFactory() {}
+  virtual Options GetOptions() const override { return options_; }
+  virtual std::string Name() const override { return "PlainTable"; }
+
+ private:
+  Options options_;
+};
+#endif  // ROCKSDB_LITE
+
+class SanityTestBloomFilter : public SanityTest {
+ public:
+  explicit SanityTestBloomFilter(const std::string& path) : SanityTest(path) {
+    BlockBasedTableOptions table_options;
+    table_options.filter_policy.reset(NewBloomFilterPolicy(10));
+    options_.table_factory.reset(NewBlockBasedTableFactory(table_options));
+  }
+  ~SanityTestBloomFilter() {}
+  virtual Options GetOptions() const override { return options_; }
+  virtual std::string Name() const override { return "BloomFilter"; }
+
+ private:
+  Options options_;
+};
+
+namespace {
+bool RunSanityTests(const std::string& command, const std::string& path) {
+  bool result = true;
+// Suppress false positive clang static anaylzer warnings.
+#ifndef __clang_analyzer__
+  std::vector<SanityTest*> sanity_tests = {
+      new SanityTestBasic(path),
+      new SanityTestSpecialComparator(path),
+      new SanityTestZlibCompression(path),
+      new SanityTestZlibCompressionVersion2(path),
+      new SanityTestLZ4Compression(path),
+      new SanityTestLZ4HCCompression(path),
+      new SanityTestZSTDCompression(path),
+#ifndef ROCKSDB_LITE
+      new SanityTestPlainTableFactory(path),
+#endif  // ROCKSDB_LITE
+      new SanityTestBloomFilter(path)};
+
+  if (command == "create") {
+    fprintf(stderr, "Creating...\n");
+  } else {
+    fprintf(stderr, "Verifying...\n");
+  }
+  for (auto sanity_test : sanity_tests) {
+    Status s;
+    fprintf(stderr, "%s -- ", sanity_test->Name().c_str());
+    if (command == "create") {
+      s = sanity_test->Create();
+    } else {
+      assert(command == "verify");
+      s = sanity_test->Verify();
+    }
+    fprintf(stderr, "%s\n", s.ToString().c_str());
+    if (!s.ok()) {
+      fprintf(stderr, "FAIL\n");
+      result = false;
+    }
+
+    delete sanity_test;
+  }
+#endif  // __clang_analyzer__
+  return result;
+}
+}  // namespace
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  std::string path, command;
+  bool ok = (argc == 3);
+  if (ok) {
+    path = std::string(argv[1]);
+    command = std::string(argv[2]);
+    ok = (command == "create" || command == "verify");
+  }
+  if (!ok) {
+    fprintf(stderr, "Usage: %s <path> [create|verify] \n", argv[0]);
+    exit(1);
+  }
+  if (path.back() != '/') {
+    path += "/";
+  }
+
+  bool sanity_ok = rocksdb::RunSanityTests(command, path);
+
+  return sanity_ok ? 0 : 1;
+}
diff --git a/src/rocksdb/tools/db_stress.cc b/src/rocksdb/tools/db_stress.cc
new file mode 100644
index 00000000..7f8c4b53
--- /dev/null
+++ b/src/rocksdb/tools/db_stress.cc
@@ -0,0 +1,4085 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+// The test uses an array to compare against values written to the database.
+// Keys written to the array are in 1:1 correspondence to the actual values in
+// the database according to the formula in the function GenerateValue.
+
+// Space is reserved in the array from 0 to FLAGS_max_key and values are
+// randomly written/deleted/read from those positions. During verification we
+// compare all the positions in the array. To shorten/elongate the running
+// time, you could change the settings: FLAGS_max_key, FLAGS_ops_per_thread,
+// (sometimes also FLAGS_threads).
+//
+// NOTE that if FLAGS_test_batches_snapshots is set, the test will have
+// different behavior. See comment of the flag for details.
+
+#ifndef GFLAGS
+#include <cstdio>
+int main() {
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+  return 1;
+}
+#else
+
+#ifndef __STDC_FORMAT_MACROS
+#define __STDC_FORMAT_MACROS
+#endif  // __STDC_FORMAT_MACROS
+
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <algorithm>
+#include <chrono>
+#include <exception>
+#include <queue>
+#include <thread>
+
+#include "db/db_impl.h"
+#include "db/version_set.h"
+#include "hdfs/env_hdfs.h"
+#include "monitoring/histogram.h"
+#include "options/options_helper.h"
+#include "port/port.h"
+#include "rocksdb/cache.h"
+#include "rocksdb/env.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/slice_transform.h"
+#include "rocksdb/statistics.h"
+#include "rocksdb/utilities/backupable_db.h"
+#include "rocksdb/utilities/checkpoint.h"
+#include "rocksdb/utilities/db_ttl.h"
+#include "rocksdb/utilities/options_util.h"
+#include "rocksdb/utilities/transaction.h"
+#include "rocksdb/utilities/transaction_db.h"
+#include "rocksdb/write_batch.h"
+#include "util/coding.h"
+#include "util/compression.h"
+#include "util/crc32c.h"
+#include "util/gflags_compat.h"
+#include "util/logging.h"
+#include "util/mutexlock.h"
+#include "util/random.h"
+#include "util/string_util.h"
+// SyncPoint is not supported in Released Windows Mode.
+#if !(defined NDEBUG) || !defined(OS_WIN)
+#include "util/sync_point.h"
+#endif  // !(defined NDEBUG) || !defined(OS_WIN)
+#include "util/testutil.h"
+
+#include "utilities/merge_operators.h"
+
+using GFLAGS_NAMESPACE::ParseCommandLineFlags;
+using GFLAGS_NAMESPACE::RegisterFlagValidator;
+using GFLAGS_NAMESPACE::SetUsageMessage;
+
+static const long KB = 1024;
+static const int kRandomValueMaxFactor = 3;
+static const int kValueMaxLen = 100;
+
+static bool ValidateUint32Range(const char* flagname, uint64_t value) {
+  if (value > std::numeric_limits<uint32_t>::max()) {
+    fprintf(stderr,
+            "Invalid value for --%s: %lu, overflow\n",
+            flagname,
+            (unsigned long)value);
+    return false;
+  }
+  return true;
+}
+
+DEFINE_uint64(seed, 2341234, "Seed for PRNG");
+static const bool FLAGS_seed_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_seed, &ValidateUint32Range);
+
+DEFINE_bool(read_only, false, "True if open DB in read-only mode during tests");
+
+DEFINE_int64(max_key, 1 * KB* KB,
+             "Max number of key/values to place in database");
+
+DEFINE_int32(column_families, 10, "Number of column families");
+
+DEFINE_string(
+    options_file, "",
+    "The path to a RocksDB options file.  If specified, then db_stress will "
+    "run with the RocksDB options in the default column family of the "
+    "specified options file. Note that, when an options file is provided, "
+    "db_stress will ignore the flag values for all options that may be passed "
+    "via options file.");
+
+DEFINE_int64(
+    active_width, 0,
+    "Number of keys in active span of the key-range at any given time. The "
+    "span begins with its left endpoint at key 0, gradually moves rightwards, "
+    "and ends with its right endpoint at max_key. If set to 0, active_width "
+    "will be sanitized to be equal to max_key.");
+
+// TODO(noetzli) Add support for single deletes
+DEFINE_bool(test_batches_snapshots, false,
+            "If set, the test uses MultiGet(), MultiPut() and MultiDelete()"
+            " which read/write/delete multiple keys in a batch. In this mode,"
+            " we do not verify db content by comparing the content with the "
+            "pre-allocated array. Instead, we do partial verification inside"
+            " MultiGet() by checking various values in a batch. Benefit of"
+            " this mode:\n"
+            "\t(a) No need to acquire mutexes during writes (less cache "
+            "flushes in multi-core leading to speed up)\n"
+            "\t(b) No long validation at the end (more speed up)\n"
+            "\t(c) Test snapshot and atomicity of batch writes");
+
+DEFINE_bool(atomic_flush, false,
+            "If set, enables atomic flush in the options.\n");
+
+DEFINE_bool(test_atomic_flush, false,
+            "If set, runs the stress test dedicated to verifying atomic flush "
+            "functionality. Setting this implies `atomic_flush=true`.\n");
+
+DEFINE_int32(threads, 32, "Number of concurrent threads to run.");
+
+DEFINE_int32(ttl, -1,
+             "Opens the db with this ttl value if this is not -1. "
+             "Carefully specify a large value such that verifications on "
+             "deleted values don't fail");
+
+DEFINE_int32(value_size_mult, 8,
+             "Size of value will be this number times rand_int(1,3) bytes");
+
+DEFINE_int32(compaction_readahead_size, 0, "Compaction readahead size");
+
+DEFINE_bool(enable_pipelined_write, false, "Pipeline WAL/memtable writes");
+
+DEFINE_bool(verify_before_write, false, "Verify before write");
+
+DEFINE_bool(histogram, false, "Print histogram of operation timings");
+
+DEFINE_bool(destroy_db_initially, true,
+            "Destroys the database dir before start if this is true");
+
+DEFINE_bool(verbose, false, "Verbose");
+
+DEFINE_bool(progress_reports, true,
+            "If true, db_stress will report number of finished operations");
+
+DEFINE_uint64(db_write_buffer_size, rocksdb::Options().db_write_buffer_size,
+              "Number of bytes to buffer in all memtables before compacting");
+
+DEFINE_int32(write_buffer_size,
+             static_cast<int32_t>(rocksdb::Options().write_buffer_size),
+             "Number of bytes to buffer in memtable before compacting");
+
+DEFINE_int32(max_write_buffer_number,
+             rocksdb::Options().max_write_buffer_number,
+             "The number of in-memory memtables. "
+             "Each memtable is of size FLAGS_write_buffer_size.");
+
+DEFINE_int32(min_write_buffer_number_to_merge,
+             rocksdb::Options().min_write_buffer_number_to_merge,
+             "The minimum number of write buffers that will be merged together "
+             "before writing to storage. This is cheap because it is an "
+             "in-memory merge. If this feature is not enabled, then all these "
+             "write buffers are flushed to L0 as separate files and this "
+             "increases read amplification because a get request has to check "
+             "in all of these files. Also, an in-memory merge may result in "
+             "writing less data to storage if there are duplicate records in"
+             " each of these individual write buffers.");
+
+DEFINE_int32(max_write_buffer_number_to_maintain,
+             rocksdb::Options().max_write_buffer_number_to_maintain,
+             "The total maximum number of write buffers to maintain in memory "
+             "including copies of buffers that have already been flushed. "
+             "Unlike max_write_buffer_number, this parameter does not affect "
+             "flushing. This controls the minimum amount of write history "
+             "that will be available in memory for conflict checking when "
+             "Transactions are used. If this value is too low, some "
+             "transactions may fail at commit time due to not being able to "
+             "determine whether there were any write conflicts. Setting this "
+             "value to 0 will cause write buffers to be freed immediately "
+             "after they are flushed.  If this value is set to -1, "
+             "'max_write_buffer_number' will be used.");
+
+DEFINE_double(memtable_prefix_bloom_size_ratio,
+              rocksdb::Options().memtable_prefix_bloom_size_ratio,
+              "creates prefix blooms for memtables, each with size "
+              "`write_buffer_size * memtable_prefix_bloom_size_ratio`.");
+
+DEFINE_bool(memtable_whole_key_filtering,
+            rocksdb::Options().memtable_whole_key_filtering,
+            "Enable whole key filtering in memtables.");
+
+DEFINE_int32(open_files, rocksdb::Options().max_open_files,
+             "Maximum number of files to keep open at the same time "
+             "(use default if == 0)");
+
+DEFINE_int64(compressed_cache_size, -1,
+             "Number of bytes to use as a cache of compressed data."
+             " Negative means use default settings.");
+
+DEFINE_int32(compaction_style, rocksdb::Options().compaction_style, "");
+
+DEFINE_int32(level0_file_num_compaction_trigger,
+             rocksdb::Options().level0_file_num_compaction_trigger,
+             "Level0 compaction start trigger");
+
+DEFINE_int32(level0_slowdown_writes_trigger,
+             rocksdb::Options().level0_slowdown_writes_trigger,
+             "Number of files in level-0 that will slow down writes");
+
+DEFINE_int32(level0_stop_writes_trigger,
+             rocksdb::Options().level0_stop_writes_trigger,
+             "Number of files in level-0 that will trigger put stop.");
+
+DEFINE_int32(block_size,
+             static_cast<int32_t>(rocksdb::BlockBasedTableOptions().block_size),
+             "Number of bytes in a block.");
+
+DEFINE_int32(
+    format_version,
+    static_cast<int32_t>(rocksdb::BlockBasedTableOptions().format_version),
+    "Format version of SST files.");
+
+DEFINE_int32(index_block_restart_interval,
+             rocksdb::BlockBasedTableOptions().index_block_restart_interval,
+             "Number of keys between restart points "
+             "for delta encoding of keys in index block.");
+
+DEFINE_int32(max_background_compactions,
+             rocksdb::Options().max_background_compactions,
+             "The maximum number of concurrent background compactions "
+             "that can occur in parallel.");
+
+DEFINE_int32(num_bottom_pri_threads, 0,
+             "The number of threads in the bottom-priority thread pool (used "
+             "by universal compaction only).");
+
+DEFINE_int32(compaction_thread_pool_adjust_interval, 0,
+             "The interval (in milliseconds) to adjust compaction thread pool "
+             "size. Don't change it periodically if the value is 0.");
+
+DEFINE_int32(compaction_thread_pool_variations, 2,
+             "Range of background thread pool size variations when adjusted "
+             "periodically.");
+
+DEFINE_int32(max_background_flushes, rocksdb::Options().max_background_flushes,
+             "The maximum number of concurrent background flushes "
+             "that can occur in parallel.");
+
+DEFINE_int32(universal_size_ratio, 0, "The ratio of file sizes that trigger"
+             " compaction in universal style");
+
+DEFINE_int32(universal_min_merge_width, 0, "The minimum number of files to "
+             "compact in universal style compaction");
+
+DEFINE_int32(universal_max_merge_width, 0, "The max number of files to compact"
+             " in universal style compaction");
+
+DEFINE_int32(universal_max_size_amplification_percent, 0,
+             "The max size amplification for universal style compaction");
+
+DEFINE_int32(clear_column_family_one_in, 1000000,
+             "With a chance of 1/N, delete a column family and then recreate "
+             "it again. If N == 0, never drop/create column families. "
+             "When test_batches_snapshots is true, this flag has no effect");
+
+DEFINE_int32(set_options_one_in, 0,
+             "With a chance of 1/N, change some random options");
+
+DEFINE_int32(set_in_place_one_in, 0,
+             "With a chance of 1/N, toggle in place support option");
+
+DEFINE_int64(cache_size, 2LL * KB * KB * KB,
+             "Number of bytes to use as a cache of uncompressed data.");
+
+DEFINE_bool(use_clock_cache, false,
+            "Replace default LRU block cache with clock cache.");
+
+DEFINE_uint64(subcompactions, 1,
+              "Maximum number of subcompactions to divide L0-L1 compactions "
+              "into.");
+
+DEFINE_bool(allow_concurrent_memtable_write, false,
+            "Allow multi-writers to update mem tables in parallel.");
+
+DEFINE_bool(enable_write_thread_adaptive_yield, true,
+            "Use a yielding spin loop for brief writer thread waits.");
+
+static const bool FLAGS_subcompactions_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_subcompactions, &ValidateUint32Range);
+
+static bool ValidateInt32Positive(const char* flagname, int32_t value) {
+  if (value < 0) {
+    fprintf(stderr, "Invalid value for --%s: %d, must be >=0\n",
+            flagname, value);
+    return false;
+  }
+  return true;
+}
+DEFINE_int32(reopen, 10, "Number of times database reopens");
+static const bool FLAGS_reopen_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_reopen, &ValidateInt32Positive);
+
+DEFINE_int32(bloom_bits, 10, "Bloom filter bits per key. "
+             "Negative means use default settings.");
+
+DEFINE_bool(use_block_based_filter, false, "use block based filter"
+              "instead of full filter for block based table");
+
+DEFINE_string(db, "", "Use the db with the following name.");
+
+DEFINE_string(
+    expected_values_path, "",
+    "File where the array of expected uint32_t values will be stored. If "
+    "provided and non-empty, the DB state will be verified against these "
+    "values after recovery. --max_key and --column_family must be kept the "
+    "same across invocations of this program that use the same "
+    "--expected_values_path.");
+
+DEFINE_bool(verify_checksum, false,
+            "Verify checksum for every block read from storage");
+
+DEFINE_bool(mmap_read, rocksdb::Options().allow_mmap_reads,
+            "Allow reads to occur via mmap-ing files");
+
+DEFINE_bool(mmap_write, rocksdb::Options().allow_mmap_writes,
+            "Allow writes to occur via mmap-ing files");
+
+DEFINE_bool(use_direct_reads, rocksdb::Options().use_direct_reads,
+            "Use O_DIRECT for reading data");
+
+DEFINE_bool(use_direct_io_for_flush_and_compaction,
+            rocksdb::Options().use_direct_io_for_flush_and_compaction,
+            "Use O_DIRECT for writing data");
+
+// Database statistics
+static std::shared_ptr<rocksdb::Statistics> dbstats;
+DEFINE_bool(statistics, false, "Create database statistics");
+
+DEFINE_bool(sync, false, "Sync all writes to disk");
+
+DEFINE_bool(use_fsync, false, "If true, issue fsync instead of fdatasync");
+
+DEFINE_int32(kill_random_test, 0,
+             "If non-zero, kill at various points in source code with "
+             "probability 1/this");
+static const bool FLAGS_kill_random_test_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_kill_random_test, &ValidateInt32Positive);
+extern int rocksdb_kill_odds;
+
+DEFINE_string(kill_prefix_blacklist, "",
+              "If non-empty, kill points with prefix in the list given will be"
+              " skipped. Items are comma-separated.");
+extern std::vector<std::string> rocksdb_kill_prefix_blacklist;
+
+DEFINE_bool(disable_wal, false, "If true, do not write WAL for write.");
+
+DEFINE_uint64(recycle_log_file_num, rocksdb::Options().recycle_log_file_num,
+              "Number of old WAL files to keep around for later recycling");
+
+DEFINE_int64(target_file_size_base, rocksdb::Options().target_file_size_base,
+             "Target level-1 file size for compaction");
+
+DEFINE_int32(target_file_size_multiplier, 1,
+             "A multiplier to compute target level-N file size (N >= 2)");
+
+DEFINE_uint64(max_bytes_for_level_base,
+              rocksdb::Options().max_bytes_for_level_base,
+              "Max bytes for level-1");
+
+DEFINE_double(max_bytes_for_level_multiplier, 2,
+              "A multiplier to compute max bytes for level-N (N >= 2)");
+
+DEFINE_int32(range_deletion_width, 10,
+             "The width of the range deletion intervals.");
+
+DEFINE_uint64(rate_limiter_bytes_per_sec, 0, "Set options.rate_limiter value.");
+
+DEFINE_bool(rate_limit_bg_reads, false,
+            "Use options.rate_limiter on compaction reads");
+
+DEFINE_bool(use_txn, false,
+            "Use TransactionDB. Currently the default write policy is "
+            "TxnDBWritePolicy::WRITE_PREPARED");
+
+DEFINE_int32(backup_one_in, 0,
+             "If non-zero, then CreateNewBackup() will be called once for "
+             "every N operations on average.  0 indicates CreateNewBackup() "
+             "is disabled.");
+
+DEFINE_int32(checkpoint_one_in, 0,
+             "If non-zero, then CreateCheckpoint() will be called once for "
+             "every N operations on average.  0 indicates CreateCheckpoint() "
+             "is disabled.");
+
+DEFINE_int32(ingest_external_file_one_in, 0,
+             "If non-zero, then IngestExternalFile() will be called once for "
+             "every N operations on average.  0 indicates IngestExternalFile() "
+             "is disabled.");
+
+DEFINE_int32(ingest_external_file_width, 1000,
+             "The width of the ingested external files.");
+
+DEFINE_int32(compact_files_one_in, 0,
+             "If non-zero, then CompactFiles() will be called once for every N "
+             "operations on average.  0 indicates CompactFiles() is disabled.");
+
+DEFINE_int32(compact_range_one_in, 0,
+             "If non-zero, then CompactRange() will be called once for every N "
+             "operations on average.  0 indicates CompactRange() is disabled.");
+
+DEFINE_int32(flush_one_in, 0,
+             "If non-zero, then Flush() will be called once for every N ops "
+             "on average.  0 indicates calls to Flush() are disabled.");
+
+DEFINE_int32(compact_range_width, 10000,
+             "The width of the ranges passed to CompactRange().");
+
+DEFINE_int32(acquire_snapshot_one_in, 0,
+             "If non-zero, then acquires a snapshot once every N operations on "
+             "average.");
+
+DEFINE_bool(compare_full_db_state_snapshot, false,
+            "If set we compare state of entire db (in one of the threads) with"
+            "each snapshot.");
+
+DEFINE_uint64(snapshot_hold_ops, 0,
+              "If non-zero, then releases snapshots N operations after they're "
+              "acquired.");
+
+static bool ValidateInt32Percent(const char* flagname, int32_t value) {
+  if (value < 0 || value>100) {
+    fprintf(stderr, "Invalid value for --%s: %d, 0<= pct <=100 \n",
+            flagname, value);
+    return false;
+  }
+  return true;
+}
+
+DEFINE_int32(readpercent, 10,
+             "Ratio of reads to total workload (expressed as a percentage)");
+static const bool FLAGS_readpercent_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_readpercent, &ValidateInt32Percent);
+
+DEFINE_int32(prefixpercent, 20,
+             "Ratio of prefix iterators to total workload (expressed as a"
+             " percentage)");
+static const bool FLAGS_prefixpercent_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_prefixpercent, &ValidateInt32Percent);
+
+DEFINE_int32(writepercent, 45,
+             "Ratio of writes to total workload (expressed as a percentage)");
+static const bool FLAGS_writepercent_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_writepercent, &ValidateInt32Percent);
+
+DEFINE_int32(delpercent, 15,
+             "Ratio of deletes to total workload (expressed as a percentage)");
+static const bool FLAGS_delpercent_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_delpercent, &ValidateInt32Percent);
+
+DEFINE_int32(delrangepercent, 0,
+             "Ratio of range deletions to total workload (expressed as a "
+             "percentage). Cannot be used with test_batches_snapshots");
+static const bool FLAGS_delrangepercent_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_delrangepercent, &ValidateInt32Percent);
+
+DEFINE_int32(nooverwritepercent, 60,
+             "Ratio of keys without overwrite to total workload (expressed as "
+             " a percentage)");
+static const bool FLAGS_nooverwritepercent_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_nooverwritepercent, &ValidateInt32Percent);
+
+DEFINE_int32(iterpercent, 10, "Ratio of iterations to total workload"
+             " (expressed as a percentage)");
+static const bool FLAGS_iterpercent_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_iterpercent, &ValidateInt32Percent);
+
+DEFINE_uint64(num_iterations, 10, "Number of iterations per MultiIterate run");
+static const bool FLAGS_num_iterations_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_num_iterations, &ValidateUint32Range);
+
+namespace {
+enum rocksdb::CompressionType StringToCompressionType(const char* ctype) {
+  assert(ctype);
+
+  if (!strcasecmp(ctype, "none"))
+    return rocksdb::kNoCompression;
+  else if (!strcasecmp(ctype, "snappy"))
+    return rocksdb::kSnappyCompression;
+  else if (!strcasecmp(ctype, "zlib"))
+    return rocksdb::kZlibCompression;
+  else if (!strcasecmp(ctype, "bzip2"))
+    return rocksdb::kBZip2Compression;
+  else if (!strcasecmp(ctype, "lz4"))
+    return rocksdb::kLZ4Compression;
+  else if (!strcasecmp(ctype, "lz4hc"))
+    return rocksdb::kLZ4HCCompression;
+  else if (!strcasecmp(ctype, "xpress"))
+    return rocksdb::kXpressCompression;
+  else if (!strcasecmp(ctype, "zstd"))
+    return rocksdb::kZSTD;
+
+  fprintf(stderr, "Cannot parse compression type '%s'\n", ctype);
+  return rocksdb::kSnappyCompression; //default value
+}
+
+enum rocksdb::ChecksumType StringToChecksumType(const char* ctype) {
+  assert(ctype);
+  auto iter = rocksdb::checksum_type_string_map.find(ctype);
+  if (iter != rocksdb::checksum_type_string_map.end()) {
+    return iter->second;
+  }
+  fprintf(stderr, "Cannot parse checksum type '%s'\n", ctype);
+  return rocksdb::kCRC32c;
+}
+
+std::string ChecksumTypeToString(rocksdb::ChecksumType ctype) {
+  auto iter = std::find_if(
+      rocksdb::checksum_type_string_map.begin(),
+      rocksdb::checksum_type_string_map.end(),
+      [&](const std::pair<std::string, rocksdb::ChecksumType>&
+              name_and_enum_val) { return name_and_enum_val.second == ctype; });
+  assert(iter != rocksdb::checksum_type_string_map.end());
+  return iter->first;
+}
+
+std::vector<std::string> SplitString(std::string src) {
+  std::vector<std::string> ret;
+  if (src.empty()) {
+    return ret;
+  }
+  size_t pos = 0;
+  size_t pos_comma;
+  while ((pos_comma = src.find(',', pos)) != std::string::npos) {
+    ret.push_back(src.substr(pos, pos_comma - pos));
+    pos = pos_comma + 1;
+  }
+  ret.push_back(src.substr(pos, src.length()));
+  return ret;
+}
+}  // namespace
+
+DEFINE_string(compression_type, "snappy",
+              "Algorithm to use to compress the database");
+static enum rocksdb::CompressionType FLAGS_compression_type_e =
+    rocksdb::kSnappyCompression;
+
+DEFINE_int32(compression_max_dict_bytes, 0,
+             "Maximum size of dictionary used to prime the compression "
+             "library.");
+
+DEFINE_int32(compression_zstd_max_train_bytes, 0,
+             "Maximum size of training data passed to zstd's dictionary "
+             "trainer.");
+
+DEFINE_string(checksum_type, "kCRC32c", "Algorithm to use to checksum blocks");
+static enum rocksdb::ChecksumType FLAGS_checksum_type_e = rocksdb::kCRC32c;
+
+DEFINE_string(hdfs, "", "Name of hdfs environment");
+// posix or hdfs environment
+static rocksdb::Env* FLAGS_env = rocksdb::Env::Default();
+
+DEFINE_uint64(ops_per_thread, 1200000, "Number of operations per thread.");
+static const bool FLAGS_ops_per_thread_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_ops_per_thread, &ValidateUint32Range);
+
+DEFINE_uint64(log2_keys_per_lock, 2, "Log2 of number of keys per lock");
+static const bool FLAGS_log2_keys_per_lock_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_log2_keys_per_lock, &ValidateUint32Range);
+
+DEFINE_uint64(max_manifest_file_size, 16384, "Maximum size of a MANIFEST file");
+
+DEFINE_bool(in_place_update, false, "On true, does inplace update in memtable");
+
+enum RepFactory {
+  kSkipList,
+  kHashSkipList,
+  kVectorRep
+};
+
+namespace {
+enum RepFactory StringToRepFactory(const char* ctype) {
+  assert(ctype);
+
+  if (!strcasecmp(ctype, "skip_list"))
+    return kSkipList;
+  else if (!strcasecmp(ctype, "prefix_hash"))
+    return kHashSkipList;
+  else if (!strcasecmp(ctype, "vector"))
+    return kVectorRep;
+
+  fprintf(stdout, "Cannot parse memreptable %s\n", ctype);
+  return kSkipList;
+}
+
+#ifdef _MSC_VER
+#pragma warning(push)
+// truncation of constant value on static_cast
+#pragma warning(disable : 4309)
+#endif
+bool GetNextPrefix(const rocksdb::Slice& src, std::string* v) {
+  std::string ret = src.ToString();
+  for (int i = static_cast<int>(ret.size()) - 1; i >= 0; i--) {
+    if (ret[i] != static_cast<char>(255)) {
+      ret[i] = ret[i] + 1;
+      break;
+    } else if (i != 0) {
+      ret[i] = 0;
+    } else {
+      // all FF. No next prefix
+      return false;
+    }
+  }
+  *v = ret;
+  return true;
+}
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+}  // namespace
+
+static enum RepFactory FLAGS_rep_factory;
+DEFINE_string(memtablerep, "prefix_hash", "");
+
+static bool ValidatePrefixSize(const char* flagname, int32_t value) {
+  if (value < 0 || value > 8) {
+    fprintf(stderr, "Invalid value for --%s: %d. 0 <= PrefixSize <= 8\n",
+            flagname, value);
+    return false;
+  }
+  return true;
+}
+DEFINE_int32(prefix_size, 7, "Control the prefix size for HashSkipListRep");
+static const bool FLAGS_prefix_size_dummy __attribute__((__unused__)) =
+    RegisterFlagValidator(&FLAGS_prefix_size, &ValidatePrefixSize);
+
+DEFINE_bool(use_merge, false, "On true, replaces all writes with a Merge "
+            "that behaves like a Put");
+
+DEFINE_bool(use_full_merge_v1, false,
+            "On true, use a merge operator that implement the deprecated "
+            "version of FullMerge");
+
+namespace rocksdb {
+
+// convert long to a big-endian slice key
+static std::string Key(int64_t val) {
+  std::string little_endian_key;
+  std::string big_endian_key;
+  PutFixed64(&little_endian_key, val);
+  assert(little_endian_key.size() == sizeof(val));
+  big_endian_key.resize(sizeof(val));
+  for (size_t i = 0 ; i < sizeof(val); ++i) {
+    big_endian_key[i] = little_endian_key[sizeof(val) - 1 - i];
+  }
+  return big_endian_key;
+}
+
+static bool GetIntVal(std::string big_endian_key, uint64_t *key_p) {
+  unsigned int size_key = sizeof(*key_p);
+  assert(big_endian_key.size() == size_key);
+  std::string little_endian_key;
+  little_endian_key.resize(size_key);
+  for (size_t i = 0 ; i < size_key; ++i) {
+    little_endian_key[i] = big_endian_key[size_key - 1 - i];
+  }
+  Slice little_endian_slice = Slice(little_endian_key);
+  return GetFixed64(&little_endian_slice, key_p);
+}
+
+static std::string StringToHex(const std::string& str) {
+  std::string result = "0x";
+  result.append(Slice(str).ToString(true));
+  return result;
+}
+
+
+class StressTest;
+namespace {
+
+class Stats {
+ private:
+  uint64_t start_;
+  uint64_t finish_;
+  double  seconds_;
+  long done_;
+  long gets_;
+  long prefixes_;
+  long writes_;
+  long deletes_;
+  size_t single_deletes_;
+  long iterator_size_sums_;
+  long founds_;
+  long iterations_;
+  long range_deletions_;
+  long covered_by_range_deletions_;
+  long errors_;
+  long num_compact_files_succeed_;
+  long num_compact_files_failed_;
+  int next_report_;
+  size_t bytes_;
+  uint64_t last_op_finish_;
+  HistogramImpl hist_;
+
+ public:
+  Stats() { }
+
+  void Start() {
+    next_report_ = 100;
+    hist_.Clear();
+    done_ = 0;
+    gets_ = 0;
+    prefixes_ = 0;
+    writes_ = 0;
+    deletes_ = 0;
+    single_deletes_ = 0;
+    iterator_size_sums_ = 0;
+    founds_ = 0;
+    iterations_ = 0;
+    range_deletions_ = 0;
+    covered_by_range_deletions_ = 0;
+    errors_ = 0;
+    bytes_ = 0;
+    seconds_ = 0;
+    num_compact_files_succeed_ = 0;
+    num_compact_files_failed_ = 0;
+    start_ = FLAGS_env->NowMicros();
+    last_op_finish_ = start_;
+    finish_ = start_;
+  }
+
+  void Merge(const Stats& other) {
+    hist_.Merge(other.hist_);
+    done_ += other.done_;
+    gets_ += other.gets_;
+    prefixes_ += other.prefixes_;
+    writes_ += other.writes_;
+    deletes_ += other.deletes_;
+    single_deletes_ += other.single_deletes_;
+    iterator_size_sums_ += other.iterator_size_sums_;
+    founds_ += other.founds_;
+    iterations_ += other.iterations_;
+    range_deletions_ += other.range_deletions_;
+    covered_by_range_deletions_ = other.covered_by_range_deletions_;
+    errors_ += other.errors_;
+    bytes_ += other.bytes_;
+    seconds_ += other.seconds_;
+    num_compact_files_succeed_ += other.num_compact_files_succeed_;
+    num_compact_files_failed_ += other.num_compact_files_failed_;
+    if (other.start_ < start_) start_ = other.start_;
+    if (other.finish_ > finish_) finish_ = other.finish_;
+  }
+
+  void Stop() {
+    finish_ = FLAGS_env->NowMicros();
+    seconds_ = (finish_ - start_) * 1e-6;
+  }
+
+  void FinishedSingleOp() {
+    if (FLAGS_histogram) {
+      auto now = FLAGS_env->NowMicros();
+      auto micros = now - last_op_finish_;
+      hist_.Add(micros);
+      if (micros > 20000) {
+        fprintf(stdout, "long op: %" PRIu64 " micros%30s\r", micros, "");
+      }
+      last_op_finish_ = now;
+    }
+
+      done_++;
+    if (FLAGS_progress_reports) {
+      if (done_ >= next_report_) {
+        if      (next_report_ < 1000)   next_report_ += 100;
+        else if (next_report_ < 5000)   next_report_ += 500;
+        else if (next_report_ < 10000)  next_report_ += 1000;
+        else if (next_report_ < 50000)  next_report_ += 5000;
+        else if (next_report_ < 100000) next_report_ += 10000;
+        else if (next_report_ < 500000) next_report_ += 50000;
+        else                            next_report_ += 100000;
+        fprintf(stdout, "... finished %ld ops%30s\r", done_, "");
+      }
+    }
+  }
+
+  void AddBytesForWrites(long nwrites, size_t nbytes) {
+    writes_ += nwrites;
+    bytes_ += nbytes;
+  }
+
+  void AddGets(long ngets, long nfounds) {
+    founds_ += nfounds;
+    gets_ += ngets;
+  }
+
+  void AddPrefixes(long nprefixes, long count) {
+    prefixes_ += nprefixes;
+    iterator_size_sums_ += count;
+  }
+
+  void AddIterations(long n) { iterations_ += n; }
+
+  void AddDeletes(long n) { deletes_ += n; }
+
+  void AddSingleDeletes(size_t n) { single_deletes_ += n; }
+
+  void AddRangeDeletions(long n) { range_deletions_ += n; }
+
+  void AddCoveredByRangeDeletions(long n) { covered_by_range_deletions_ += n; }
+
+  void AddErrors(long n) { errors_ += n; }
+
+  void AddNumCompactFilesSucceed(long n) { num_compact_files_succeed_ += n; }
+
+  void AddNumCompactFilesFailed(long n) { num_compact_files_failed_ += n; }
+
+  void Report(const char* name) {
+    std::string extra;
+    if (bytes_ < 1 || done_ < 1) {
+      fprintf(stderr, "No writes or ops?\n");
+      return;
+    }
+
+    double elapsed = (finish_ - start_) * 1e-6;
+    double bytes_mb = bytes_ / 1048576.0;
+    double rate = bytes_mb / elapsed;
+    double throughput = (double)done_/elapsed;
+
+    fprintf(stdout, "%-12s: ", name);
+    fprintf(stdout, "%.3f micros/op %ld ops/sec\n",
+            seconds_ * 1e6 / done_, (long)throughput);
+    fprintf(stdout, "%-12s: Wrote %.2f MB (%.2f MB/sec) (%ld%% of %ld ops)\n",
+            "", bytes_mb, rate, (100*writes_)/done_, done_);
+    fprintf(stdout, "%-12s: Wrote %ld times\n", "", writes_);
+    fprintf(stdout, "%-12s: Deleted %ld times\n", "", deletes_);
+    fprintf(stdout, "%-12s: Single deleted %" ROCKSDB_PRIszt " times\n", "",
+           single_deletes_);
+    fprintf(stdout, "%-12s: %ld read and %ld found the key\n", "",
+            gets_, founds_);
+    fprintf(stdout, "%-12s: Prefix scanned %ld times\n", "", prefixes_);
+    fprintf(stdout, "%-12s: Iterator size sum is %ld\n", "",
+            iterator_size_sums_);
+    fprintf(stdout, "%-12s: Iterated %ld times\n", "", iterations_);
+    fprintf(stdout, "%-12s: Deleted %ld key-ranges\n", "", range_deletions_);
+    fprintf(stdout, "%-12s: Range deletions covered %ld keys\n", "",
+            covered_by_range_deletions_);
+
+    fprintf(stdout, "%-12s: Got errors %ld times\n", "", errors_);
+    fprintf(stdout, "%-12s: %ld CompactFiles() succeed\n", "",
+            num_compact_files_succeed_);
+    fprintf(stdout, "%-12s: %ld CompactFiles() did not succeed\n", "",
+            num_compact_files_failed_);
+
+    if (FLAGS_histogram) {
+      fprintf(stdout, "Microseconds per op:\n%s\n", hist_.ToString().c_str());
+    }
+    fflush(stdout);
+  }
+};
+
+// State shared by all concurrent executions of the same benchmark.
+class SharedState {
+ public:
+  // indicates a key may have any value (or not be present) as an operation on
+  // it is incomplete.
+  static const uint32_t UNKNOWN_SENTINEL;
+  // indicates a key should definitely be deleted
+  static const uint32_t DELETION_SENTINEL;
+
+  explicit SharedState(StressTest* stress_test)
+      : cv_(&mu_),
+        seed_(static_cast<uint32_t>(FLAGS_seed)),
+        max_key_(FLAGS_max_key),
+        log2_keys_per_lock_(static_cast<uint32_t>(FLAGS_log2_keys_per_lock)),
+        num_threads_(FLAGS_threads),
+        num_initialized_(0),
+        num_populated_(0),
+        vote_reopen_(0),
+        num_done_(0),
+        start_(false),
+        start_verify_(false),
+        should_stop_bg_thread_(false),
+        bg_thread_finished_(false),
+        stress_test_(stress_test),
+        verification_failure_(false),
+        no_overwrite_ids_(FLAGS_column_families),
+        values_(nullptr) {
+    // Pick random keys in each column family that will not experience
+    // overwrite
+
+    printf("Choosing random keys with no overwrite\n");
+    Random64 rnd(seed_);
+    // Start with the identity permutation. Subsequent iterations of
+    // for loop below will start with perm of previous for loop
+    int64_t *permutation = new int64_t[max_key_];
+    for (int64_t i = 0; i < max_key_; i++) {
+      permutation[i] = i;
+    }
+    // Now do the Knuth shuffle
+    int64_t num_no_overwrite_keys = (max_key_ * FLAGS_nooverwritepercent) / 100;
+    // Only need to figure out first num_no_overwrite_keys of permutation
+    no_overwrite_ids_.reserve(num_no_overwrite_keys);
+    for (int64_t i = 0; i < num_no_overwrite_keys; i++) {
+      int64_t rand_index = i + rnd.Next() % (max_key_ - i);
+      // Swap i and rand_index;
+      int64_t temp = permutation[i];
+      permutation[i] = permutation[rand_index];
+      permutation[rand_index] = temp;
+      // Fill no_overwrite_ids_ with the first num_no_overwrite_keys of
+      // permutation
+      no_overwrite_ids_.insert(permutation[i]);
+    }
+    delete[] permutation;
+
+    size_t expected_values_size =
+        sizeof(std::atomic<uint32_t>) * FLAGS_column_families * max_key_;
+    bool values_init_needed = false;
+    Status status;
+    if (!FLAGS_expected_values_path.empty()) {
+      if (!std::atomic<uint32_t>{}.is_lock_free()) {
+        status = Status::InvalidArgument(
+            "Cannot use --expected_values_path on platforms without lock-free "
+            "std::atomic<uint32_t>");
+      }
+      if (status.ok() && FLAGS_clear_column_family_one_in > 0) {
+        status = Status::InvalidArgument(
+            "Cannot use --expected_values_path on when "
+            "--clear_column_family_one_in is greater than zero.");
+      }
+      uint64_t size = 0;
+      if (status.ok()) {
+        status = FLAGS_env->GetFileSize(FLAGS_expected_values_path, &size);
+      }
+      std::unique_ptr<WritableFile> wfile;
+      if (status.ok() && size == 0) {
+        const EnvOptions soptions;
+        status = FLAGS_env->NewWritableFile(FLAGS_expected_values_path, &wfile,
+                                            soptions);
+      }
+      if (status.ok() && size == 0) {
+        std::string buf(expected_values_size, '\0');
+        status = wfile->Append(buf);
+        values_init_needed = true;
+      }
+      if (status.ok()) {
+        status = FLAGS_env->NewMemoryMappedFileBuffer(
+            FLAGS_expected_values_path, &expected_mmap_buffer_);
+      }
+      if (status.ok()) {
+        assert(expected_mmap_buffer_->GetLen() == expected_values_size);
+        values_ =
+            static_cast<std::atomic<uint32_t>*>(expected_mmap_buffer_->GetBase());
+        assert(values_ != nullptr);
+      } else {
+        fprintf(stderr, "Failed opening shared file '%s' with error: %s\n",
+                FLAGS_expected_values_path.c_str(), status.ToString().c_str());
+        assert(values_ == nullptr);
+      }
+    }
+    if (values_ == nullptr) {
+      values_allocation_.reset(
+          new std::atomic<uint32_t>[FLAGS_column_families * max_key_]);
+      values_ = &values_allocation_[0];
+      values_init_needed = true;
+    }
+    assert(values_ != nullptr);
+    if (values_init_needed) {
+      for (int i = 0; i < FLAGS_column_families; ++i) {
+        for (int j = 0; j < max_key_; ++j) {
+          Delete(i, j, false /* pending */);
+        }
+      }
+    }
+
+    if (FLAGS_test_batches_snapshots) {
+      fprintf(stdout, "No lock creation because test_batches_snapshots set\n");
+      return;
+    }
+
+    long num_locks = static_cast<long>(max_key_ >> log2_keys_per_lock_);
+    if (max_key_ & ((1 << log2_keys_per_lock_) - 1)) {
+      num_locks++;
+    }
+    fprintf(stdout, "Creating %ld locks\n", num_locks * FLAGS_column_families);
+    key_locks_.resize(FLAGS_column_families);
+
+    for (int i = 0; i < FLAGS_column_families; ++i) {
+      key_locks_[i].resize(num_locks);
+      for (auto& ptr : key_locks_[i]) {
+        ptr.reset(new port::Mutex);
+      }
+    }
+  }
+
+  ~SharedState() {}
+
+  port::Mutex* GetMutex() {
+    return &mu_;
+  }
+
+  port::CondVar* GetCondVar() {
+    return &cv_;
+  }
+
+  StressTest* GetStressTest() const {
+    return stress_test_;
+  }
+
+  int64_t GetMaxKey() const {
+    return max_key_;
+  }
+
+  uint32_t GetNumThreads() const {
+    return num_threads_;
+  }
+
+  void IncInitialized() {
+    num_initialized_++;
+  }
+
+  void IncOperated() {
+    num_populated_++;
+  }
+
+  void IncDone() {
+    num_done_++;
+  }
+
+  void IncVotedReopen() {
+    vote_reopen_ = (vote_reopen_ + 1) % num_threads_;
+  }
+
+  bool AllInitialized() const {
+    return num_initialized_ >= num_threads_;
+  }
+
+  bool AllOperated() const {
+    return num_populated_ >= num_threads_;
+  }
+
+  bool AllDone() const {
+    return num_done_ >= num_threads_;
+  }
+
+  bool AllVotedReopen() {
+    return (vote_reopen_ == 0);
+  }
+
+  void SetStart() {
+    start_ = true;
+  }
+
+  void SetStartVerify() {
+    start_verify_ = true;
+  }
+
+  bool Started() const {
+    return start_;
+  }
+
+  bool VerifyStarted() const {
+    return start_verify_;
+  }
+
+  void SetVerificationFailure() { verification_failure_.store(true); }
+
+  bool HasVerificationFailedYet() { return verification_failure_.load(); }
+
+  port::Mutex* GetMutexForKey(int cf, int64_t key) {
+    return key_locks_[cf][key >> log2_keys_per_lock_].get();
+  }
+
+  void LockColumnFamily(int cf) {
+    for (auto& mutex : key_locks_[cf]) {
+      mutex->Lock();
+    }
+  }
+
+  void UnlockColumnFamily(int cf) {
+    for (auto& mutex : key_locks_[cf]) {
+      mutex->Unlock();
+    }
+  }
+
+  std::atomic<uint32_t>& Value(int cf, int64_t key) const {
+    return values_[cf * max_key_ + key];
+  }
+
+  void ClearColumnFamily(int cf) {
+    std::fill(&Value(cf, 0 /* key */), &Value(cf + 1, 0 /* key */),
+              DELETION_SENTINEL);
+  }
+
+  // @param pending True if the update may have started but is not yet
+  //    guaranteed finished. This is useful for crash-recovery testing when the
+  //    process may crash before updating the expected values array.
+  void Put(int cf, int64_t key, uint32_t value_base, bool pending) {
+    if (!pending) {
+      // prevent expected-value update from reordering before Write
+      std::atomic_thread_fence(std::memory_order_release);
+    }
+    Value(cf, key).store(pending ? UNKNOWN_SENTINEL : value_base,
+                         std::memory_order_relaxed);
+    if (pending) {
+      // prevent Write from reordering before expected-value update
+      std::atomic_thread_fence(std::memory_order_release);
+    }
+  }
+
+  uint32_t Get(int cf, int64_t key) const { return Value(cf, key); }
+
+  // @param pending See comment above Put()
+  // Returns true if the key was not yet deleted.
+  bool Delete(int cf, int64_t key, bool pending) {
+    if (Value(cf, key) == DELETION_SENTINEL) {
+      return false;
+    }
+    Put(cf, key, DELETION_SENTINEL, pending);
+    return true;
+  }
+
+  // @param pending See comment above Put()
+  // Returns true if the key was not yet deleted.
+  bool SingleDelete(int cf, int64_t key, bool pending) {
+    return Delete(cf, key, pending);
+  }
+
+  // @param pending See comment above Put()
+  // Returns number of keys deleted by the call.
+  int DeleteRange(int cf, int64_t begin_key, int64_t end_key, bool pending) {
+    int covered = 0;
+    for (int64_t key = begin_key; key < end_key; ++key) {
+      if (Delete(cf, key, pending)) {
+        ++covered;
+      }
+    }
+    return covered;
+  }
+
+  bool AllowsOverwrite(int64_t key) {
+    return no_overwrite_ids_.find(key) == no_overwrite_ids_.end();
+  }
+
+  bool Exists(int cf, int64_t key) {
+    // UNKNOWN_SENTINEL counts as exists. That assures a key for which overwrite
+    // is disallowed can't be accidentally added a second time, in which case
+    // SingleDelete wouldn't be able to properly delete the key. It does allow
+    // the case where a SingleDelete might be added which covers nothing, but
+    // that's not a correctness issue.
+    uint32_t expected_value = Value(cf, key).load();
+    return expected_value != DELETION_SENTINEL;
+  }
+
+  uint32_t GetSeed() const { return seed_; }
+
+  void SetShouldStopBgThread() { should_stop_bg_thread_ = true; }
+
+  bool ShoudStopBgThread() { return should_stop_bg_thread_; }
+
+  void SetBgThreadFinish() { bg_thread_finished_ = true; }
+
+  bool BgThreadFinished() const { return bg_thread_finished_; }
+
+  bool ShouldVerifyAtBeginning() const {
+    return expected_mmap_buffer_.get() != nullptr;
+  }
+
+ private:
+  port::Mutex mu_;
+  port::CondVar cv_;
+  const uint32_t seed_;
+  const int64_t max_key_;
+  const uint32_t log2_keys_per_lock_;
+  const int num_threads_;
+  long num_initialized_;
+  long num_populated_;
+  long vote_reopen_;
+  long num_done_;
+  bool start_;
+  bool start_verify_;
+  bool should_stop_bg_thread_;
+  bool bg_thread_finished_;
+  StressTest* stress_test_;
+  std::atomic<bool> verification_failure_;
+
+  // Keys that should not be overwritten
+  std::unordered_set<size_t> no_overwrite_ids_;
+
+  std::atomic<uint32_t>* values_;
+  std::unique_ptr<std::atomic<uint32_t>[]> values_allocation_;
+  // Has to make it owned by a smart ptr as port::Mutex is not copyable
+  // and storing it in the container may require copying depending on the impl.
+  std::vector<std::vector<std::unique_ptr<port::Mutex> > > key_locks_;
+  std::unique_ptr<MemoryMappedFileBuffer> expected_mmap_buffer_;
+};
+
+const uint32_t SharedState::UNKNOWN_SENTINEL = 0xfffffffe;
+const uint32_t SharedState::DELETION_SENTINEL = 0xffffffff;
+
+// Per-thread state for concurrent executions of the same benchmark.
+struct ThreadState {
+  uint32_t tid;  // 0..n-1
+  Random rand;   // Has different seeds for different threads
+  SharedState* shared;
+  Stats stats;
+  struct SnapshotState {
+    const Snapshot* snapshot;
+    // The cf from which we did a Get at this snapshot
+    int cf_at;
+    // The name of the cf at the time that we did a read
+    std::string cf_at_name;
+    // The key with which we did a Get at this snapshot
+    std::string key;
+    // The status of the Get
+    Status status;
+    // The value of the Get
+    std::string value;
+    // optional state of all keys in the db
+    std::vector<bool> *key_vec;
+  };
+  std::queue<std::pair<uint64_t, SnapshotState> > snapshot_queue;
+
+  ThreadState(uint32_t index, SharedState* _shared)
+      : tid(index), rand(1000 + index + _shared->GetSeed()), shared(_shared) {}
+};
+
+class DbStressListener : public EventListener {
+ public:
+  DbStressListener(const std::string& db_name,
+                   const std::vector<DbPath>& db_paths,
+                   const std::vector<ColumnFamilyDescriptor>& column_families)
+      : db_name_(db_name),
+        db_paths_(db_paths),
+        column_families_(column_families),
+        num_pending_file_creations_(0) {}
+  virtual ~DbStressListener() {
+    assert(num_pending_file_creations_ == 0);
+  }
+#ifndef ROCKSDB_LITE
+  virtual void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
+    assert(IsValidColumnFamilyName(info.cf_name));
+    VerifyFilePath(info.file_path);
+    // pretending doing some work here
+    std::this_thread::sleep_for(
+        std::chrono::microseconds(Random::GetTLSInstance()->Uniform(5000)));
+  }
+
+  virtual void OnCompactionCompleted(DB* /*db*/,
+                                     const CompactionJobInfo& ci) override {
+    assert(IsValidColumnFamilyName(ci.cf_name));
+    assert(ci.input_files.size() + ci.output_files.size() > 0U);
+    for (const auto& file_path : ci.input_files) {
+      VerifyFilePath(file_path);
+    }
+    for (const auto& file_path : ci.output_files) {
+      VerifyFilePath(file_path);
+    }
+    // pretending doing some work here
+    std::this_thread::sleep_for(
+        std::chrono::microseconds(Random::GetTLSInstance()->Uniform(5000)));
+  }
+
+  virtual void OnTableFileCreationStarted(
+      const TableFileCreationBriefInfo& /*info*/) override {
+    ++num_pending_file_creations_;
+  }
+  virtual void OnTableFileCreated(const TableFileCreationInfo& info) override {
+    assert(info.db_name == db_name_);
+    assert(IsValidColumnFamilyName(info.cf_name));
+    if (info.file_size) {
+      VerifyFilePath(info.file_path);
+    }
+    assert(info.job_id > 0 || FLAGS_compact_files_one_in > 0);
+    if (info.status.ok() && info.file_size > 0) {
+      assert(info.table_properties.data_size > 0 ||
+             info.table_properties.num_range_deletions > 0);
+      assert(info.table_properties.raw_key_size > 0);
+      assert(info.table_properties.num_entries > 0);
+    }
+    --num_pending_file_creations_;
+  }
+
+ protected:
+  bool IsValidColumnFamilyName(const std::string& cf_name) const {
+    if (cf_name == kDefaultColumnFamilyName) {
+      return true;
+    }
+    // The column family names in the stress tests are numbers.
+    for (size_t i = 0; i < cf_name.size(); ++i) {
+      if (cf_name[i] < '0' || cf_name[i] > '9') {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  void VerifyFileDir(const std::string& file_dir) {
+#ifndef NDEBUG
+    if (db_name_ == file_dir) {
+      return;
+    }
+    for (const auto& db_path : db_paths_) {
+      if (db_path.path == file_dir) {
+        return;
+      }
+    }
+    for (auto& cf : column_families_) {
+      for (const auto& cf_path : cf.options.cf_paths) {
+        if (cf_path.path == file_dir) {
+            return;
+        }
+      }
+    }
+    assert(false);
+#else
+    (void)file_dir;
+#endif  // !NDEBUG
+  }
+
+  void VerifyFileName(const std::string& file_name) {
+#ifndef NDEBUG
+    uint64_t file_number;
+    FileType file_type;
+    bool result = ParseFileName(file_name, &file_number, &file_type);
+    assert(result);
+    assert(file_type == kTableFile);
+#else
+    (void)file_name;
+#endif  // !NDEBUG
+  }
+
+  void VerifyFilePath(const std::string& file_path) {
+#ifndef NDEBUG
+    size_t pos = file_path.find_last_of("/");
+    if (pos == std::string::npos) {
+      VerifyFileName(file_path);
+    } else {
+      if (pos > 0) {
+        VerifyFileDir(file_path.substr(0, pos));
+      }
+      VerifyFileName(file_path.substr(pos));
+    }
+#else
+    (void)file_path;
+#endif  // !NDEBUG
+  }
+#endif  // !ROCKSDB_LITE
+
+ private:
+  std::string db_name_;
+  std::vector<DbPath> db_paths_;
+  std::vector<ColumnFamilyDescriptor> column_families_;
+  std::atomic<int> num_pending_file_creations_;
+};
+
+}  // namespace
+
+class StressTest {
+ public:
+  StressTest()
+      : cache_(NewCache(FLAGS_cache_size)),
+        compressed_cache_(NewLRUCache(FLAGS_compressed_cache_size)),
+        filter_policy_(FLAGS_bloom_bits >= 0
+                           ? FLAGS_use_block_based_filter
+                                 ? NewBloomFilterPolicy(FLAGS_bloom_bits, true)
+                                 : NewBloomFilterPolicy(FLAGS_bloom_bits, false)
+                           : nullptr),
+        db_(nullptr),
+#ifndef ROCKSDB_LITE
+        txn_db_(nullptr),
+#endif
+        new_column_family_name_(1),
+        num_times_reopened_(0),
+        db_preload_finished_(false) {
+    if (FLAGS_destroy_db_initially) {
+      std::vector<std::string> files;
+      FLAGS_env->GetChildren(FLAGS_db, &files);
+      for (unsigned int i = 0; i < files.size(); i++) {
+        if (Slice(files[i]).starts_with("heap-")) {
+          FLAGS_env->DeleteFile(FLAGS_db + "/" + files[i]);
+        }
+      }
+      Options options;
+      options.env = FLAGS_env;
+      Status s = DestroyDB(FLAGS_db, options);
+      if (!s.ok()) {
+        fprintf(stderr, "Cannot destroy original db: %s\n",
+                s.ToString().c_str());
+        exit(1);
+      }
+    }
+  }
+
+  virtual ~StressTest() {
+    for (auto cf : column_families_) {
+      delete cf;
+    }
+    column_families_.clear();
+    delete db_;
+  }
+
+  std::shared_ptr<Cache> NewCache(size_t capacity) {
+    if (capacity <= 0) {
+      return nullptr;
+    }
+    if (FLAGS_use_clock_cache) {
+      auto cache = NewClockCache((size_t)capacity);
+      if (!cache) {
+        fprintf(stderr, "Clock cache not supported.");
+        exit(1);
+      }
+      return cache;
+    } else {
+      return NewLRUCache((size_t)capacity);
+    }
+  }
+
+  bool BuildOptionsTable() {
+    if (FLAGS_set_options_one_in <= 0) {
+      return true;
+    }
+
+    std::unordered_map<std::string, std::vector<std::string> > options_tbl = {
+        {"write_buffer_size",
+         {ToString(options_.write_buffer_size),
+          ToString(options_.write_buffer_size * 2),
+          ToString(options_.write_buffer_size * 4)}},
+        {"max_write_buffer_number",
+         {ToString(options_.max_write_buffer_number),
+          ToString(options_.max_write_buffer_number * 2),
+          ToString(options_.max_write_buffer_number * 4)}},
+        {"arena_block_size",
+         {
+             ToString(options_.arena_block_size),
+             ToString(options_.write_buffer_size / 4),
+             ToString(options_.write_buffer_size / 8),
+         }},
+        {"memtable_huge_page_size", {"0", ToString(2 * 1024 * 1024)}},
+        {"max_successive_merges", {"0", "2", "4"}},
+        {"inplace_update_num_locks", {"100", "200", "300"}},
+        // TODO(ljin): enable test for this option
+        // {"disable_auto_compactions", {"100", "200", "300"}},
+        {"soft_rate_limit", {"0", "0.5", "0.9"}},
+        {"hard_rate_limit", {"0", "1.1", "2.0"}},
+        {"level0_file_num_compaction_trigger",
+         {
+             ToString(options_.level0_file_num_compaction_trigger),
+             ToString(options_.level0_file_num_compaction_trigger + 2),
+             ToString(options_.level0_file_num_compaction_trigger + 4),
+         }},
+        {"level0_slowdown_writes_trigger",
+         {
+             ToString(options_.level0_slowdown_writes_trigger),
+             ToString(options_.level0_slowdown_writes_trigger + 2),
+             ToString(options_.level0_slowdown_writes_trigger + 4),
+         }},
+        {"level0_stop_writes_trigger",
+         {
+             ToString(options_.level0_stop_writes_trigger),
+             ToString(options_.level0_stop_writes_trigger + 2),
+             ToString(options_.level0_stop_writes_trigger + 4),
+         }},
+        {"max_compaction_bytes",
+         {
+             ToString(options_.target_file_size_base * 5),
+             ToString(options_.target_file_size_base * 15),
+             ToString(options_.target_file_size_base * 100),
+         }},
+        {"target_file_size_base",
+         {
+             ToString(options_.target_file_size_base),
+             ToString(options_.target_file_size_base * 2),
+             ToString(options_.target_file_size_base * 4),
+         }},
+        {"target_file_size_multiplier",
+         {
+             ToString(options_.target_file_size_multiplier), "1", "2",
+         }},
+        {"max_bytes_for_level_base",
+         {
+             ToString(options_.max_bytes_for_level_base / 2),
+             ToString(options_.max_bytes_for_level_base),
+             ToString(options_.max_bytes_for_level_base * 2),
+         }},
+        {"max_bytes_for_level_multiplier",
+         {
+             ToString(options_.max_bytes_for_level_multiplier), "1", "2",
+         }},
+        {"max_sequential_skip_in_iterations", {"4", "8", "12"}},
+    };
+
+    options_table_ = std::move(options_tbl);
+
+    for (const auto& iter : options_table_) {
+      options_index_.push_back(iter.first);
+    }
+    return true;
+  }
+
+  bool Run() {
+    uint64_t now = FLAGS_env->NowMicros();
+    fprintf(stdout, "%s Initializing db_stress\n",
+            FLAGS_env->TimeToString(now / 1000000).c_str());
+    PrintEnv();
+    Open();
+    BuildOptionsTable();
+    SharedState shared(this);
+
+    if (FLAGS_read_only) {
+      now = FLAGS_env->NowMicros();
+      fprintf(stdout, "%s Preloading db with %" PRIu64 " KVs\n",
+              FLAGS_env->TimeToString(now / 1000000).c_str(), FLAGS_max_key);
+      PreloadDbAndReopenAsReadOnly(FLAGS_max_key, &shared);
+    }
+    uint32_t n = shared.GetNumThreads();
+
+    now = FLAGS_env->NowMicros();
+    fprintf(stdout, "%s Initializing worker threads\n",
+            FLAGS_env->TimeToString(now / 1000000).c_str());
+    std::vector<ThreadState*> threads(n);
+    for (uint32_t i = 0; i < n; i++) {
+      threads[i] = new ThreadState(i, &shared);
+      FLAGS_env->StartThread(ThreadBody, threads[i]);
+    }
+    ThreadState bg_thread(0, &shared);
+    if (FLAGS_compaction_thread_pool_adjust_interval > 0) {
+      FLAGS_env->StartThread(PoolSizeChangeThread, &bg_thread);
+    }
+
+    // Each thread goes through the following states:
+    // initializing -> wait for others to init -> read/populate/depopulate
+    // wait for others to operate -> verify -> done
+
+    {
+      MutexLock l(shared.GetMutex());
+      while (!shared.AllInitialized()) {
+        shared.GetCondVar()->Wait();
+      }
+      if (shared.ShouldVerifyAtBeginning()) {
+        if (shared.HasVerificationFailedYet()) {
+          printf("Crash-recovery verification failed :(\n");
+        } else {
+          printf("Crash-recovery verification passed :)\n");
+        }
+      }
+
+      now = FLAGS_env->NowMicros();
+      fprintf(stdout, "%s Starting database operations\n",
+              FLAGS_env->TimeToString(now/1000000).c_str());
+
+      shared.SetStart();
+      shared.GetCondVar()->SignalAll();
+      while (!shared.AllOperated()) {
+        shared.GetCondVar()->Wait();
+      }
+
+      now = FLAGS_env->NowMicros();
+      if (FLAGS_test_batches_snapshots) {
+        fprintf(stdout, "%s Limited verification already done during gets\n",
+                FLAGS_env->TimeToString((uint64_t) now/1000000).c_str());
+      } else {
+        fprintf(stdout, "%s Starting verification\n",
+                FLAGS_env->TimeToString((uint64_t) now/1000000).c_str());
+      }
+
+      shared.SetStartVerify();
+      shared.GetCondVar()->SignalAll();
+      while (!shared.AllDone()) {
+        shared.GetCondVar()->Wait();
+      }
+    }
+
+    for (unsigned int i = 1; i < n; i++) {
+      threads[0]->stats.Merge(threads[i]->stats);
+    }
+    threads[0]->stats.Report("Stress Test");
+
+    for (unsigned int i = 0; i < n; i++) {
+      delete threads[i];
+      threads[i] = nullptr;
+    }
+    now = FLAGS_env->NowMicros();
+    if (!FLAGS_test_batches_snapshots && !shared.HasVerificationFailedYet()) {
+      fprintf(stdout, "%s Verification successful\n",
+              FLAGS_env->TimeToString(now/1000000).c_str());
+    }
+    PrintStatistics();
+
+    if (FLAGS_compaction_thread_pool_adjust_interval > 0) {
+      MutexLock l(shared.GetMutex());
+      shared.SetShouldStopBgThread();
+      while (!shared.BgThreadFinished()) {
+        shared.GetCondVar()->Wait();
+      }
+    }
+
+    if (shared.HasVerificationFailedYet()) {
+      printf("Verification failed :(\n");
+      return false;
+    }
+    return true;
+  }
+
+ protected:
+  static void ThreadBody(void* v) {
+    ThreadState* thread = reinterpret_cast<ThreadState*>(v);
+    SharedState* shared = thread->shared;
+
+    if (shared->ShouldVerifyAtBeginning()) {
+      thread->shared->GetStressTest()->VerifyDb(thread);
+    }
+    {
+      MutexLock l(shared->GetMutex());
+      shared->IncInitialized();
+      if (shared->AllInitialized()) {
+        shared->GetCondVar()->SignalAll();
+      }
+      while (!shared->Started()) {
+        shared->GetCondVar()->Wait();
+      }
+    }
+    thread->shared->GetStressTest()->OperateDb(thread);
+
+    {
+      MutexLock l(shared->GetMutex());
+      shared->IncOperated();
+      if (shared->AllOperated()) {
+        shared->GetCondVar()->SignalAll();
+      }
+      while (!shared->VerifyStarted()) {
+        shared->GetCondVar()->Wait();
+      }
+    }
+
+    thread->shared->GetStressTest()->VerifyDb(thread);
+
+    {
+      MutexLock l(shared->GetMutex());
+      shared->IncDone();
+      if (shared->AllDone()) {
+        shared->GetCondVar()->SignalAll();
+      }
+    }
+  }
+
+  static void PoolSizeChangeThread(void* v) {
+    assert(FLAGS_compaction_thread_pool_adjust_interval > 0);
+    ThreadState* thread = reinterpret_cast<ThreadState*>(v);
+    SharedState* shared = thread->shared;
+
+    while (true) {
+      {
+        MutexLock l(shared->GetMutex());
+        if (shared->ShoudStopBgThread()) {
+          shared->SetBgThreadFinish();
+          shared->GetCondVar()->SignalAll();
+          return;
+        }
+      }
+
+      auto thread_pool_size_base = FLAGS_max_background_compactions;
+      auto thread_pool_size_var = FLAGS_compaction_thread_pool_variations;
+      int new_thread_pool_size =
+          thread_pool_size_base - thread_pool_size_var +
+          thread->rand.Next() % (thread_pool_size_var * 2 + 1);
+      if (new_thread_pool_size < 1) {
+        new_thread_pool_size = 1;
+      }
+      FLAGS_env->SetBackgroundThreads(new_thread_pool_size);
+      // Sleep up to 3 seconds
+      FLAGS_env->SleepForMicroseconds(
+          thread->rand.Next() % FLAGS_compaction_thread_pool_adjust_interval *
+              1000 +
+          1);
+    }
+  }
+
+  static void PrintKeyValue(int cf, uint64_t key, const char* value,
+      size_t sz) {
+    if (!FLAGS_verbose) {
+      return;
+    }
+    std::string tmp;
+    tmp.reserve(sz * 2 + 16);
+    char buf[4];
+    for (size_t i = 0; i < sz; i++) {
+      snprintf(buf, 4, "%X", value[i]);
+      tmp.append(buf);
+    }
+    fprintf(stdout, "[CF %d] %" PRIi64 " == > (%" ROCKSDB_PRIszt ") %s\n", cf,
+            key, sz, tmp.c_str());
+  }
+
+  static int64_t GenerateOneKey(ThreadState* thread, uint64_t iteration) {
+    const double completed_ratio =
+        static_cast<double>(iteration) / FLAGS_ops_per_thread;
+    const int64_t base_key = static_cast<int64_t>(
+        completed_ratio * (FLAGS_max_key - FLAGS_active_width));
+    return base_key + thread->rand.Next() % FLAGS_active_width;
+  }
+
+  static size_t GenerateValue(uint32_t rand, char *v, size_t max_sz) {
+    size_t value_sz =
+        ((rand % kRandomValueMaxFactor) + 1) * FLAGS_value_size_mult;
+    assert(value_sz <= max_sz && value_sz >= sizeof(uint32_t));
+    (void) max_sz;
+    *((uint32_t*)v) = rand;
+    for (size_t i=sizeof(uint32_t); i < value_sz; i++) {
+      v[i] = (char)(rand ^ i);
+    }
+    v[value_sz] = '\0';
+    return value_sz; // the size of the value set.
+  }
+
+  Status AssertSame(DB* db, ColumnFamilyHandle* cf,
+                    ThreadState::SnapshotState& snap_state) {
+    Status s;
+    if (cf->GetName() != snap_state.cf_at_name) {
+      return s;
+    }
+    ReadOptions ropt;
+    ropt.snapshot = snap_state.snapshot;
+    PinnableSlice exp_v(&snap_state.value);
+    exp_v.PinSelf();
+    PinnableSlice v;
+    s = db->Get(ropt, cf, snap_state.key, &v);
+    if (!s.ok() && !s.IsNotFound()) {
+      return s;
+    }
+    if (snap_state.status != s) {
+      return Status::Corruption(
+          "The snapshot gave inconsistent results for key " +
+          ToString(Hash(snap_state.key.c_str(), snap_state.key.size(), 0)) +
+          " in cf " + cf->GetName() + ": (" + snap_state.status.ToString() +
+          ") vs. (" + s.ToString() + ")");
+    }
+    if (s.ok()) {
+      if (exp_v != v) {
+        return Status::Corruption("The snapshot gave inconsistent values: (" +
+                                  exp_v.ToString() + ") vs. (" + v.ToString() +
+                                  ")");
+      }
+    }
+    if (snap_state.key_vec != nullptr) {
+      // When `prefix_extractor` is set, seeking to beginning and scanning
+      // across prefixes are only supported with `total_order_seek` set.
+      ropt.total_order_seek = true;
+      std::unique_ptr<Iterator> iterator(db->NewIterator(ropt));
+      std::unique_ptr<std::vector<bool>> tmp_bitvec(new std::vector<bool>(FLAGS_max_key));
+      for (iterator->SeekToFirst(); iterator->Valid(); iterator->Next()) {
+        uint64_t key_val;
+        if (GetIntVal(iterator->key().ToString(), &key_val)) {
+          (*tmp_bitvec.get())[key_val] = true;
+        }
+      }
+      if (!std::equal(snap_state.key_vec->begin(),
+                      snap_state.key_vec->end(),
+                      tmp_bitvec.get()->begin())) {
+        return Status::Corruption("Found inconsistent keys at this snapshot");
+      }
+    }
+    return Status::OK();
+  }
+
+  // Currently PreloadDb has to be single-threaded.
+  void PreloadDbAndReopenAsReadOnly(int64_t number_of_keys,
+                                    SharedState* shared) {
+    WriteOptions write_opts;
+    write_opts.disableWAL = FLAGS_disable_wal;
+    if (FLAGS_sync) {
+      write_opts.sync = true;
+    }
+    char value[100];
+    int cf_idx = 0;
+    Status s;
+    for (auto cfh : column_families_) {
+      for (int64_t k = 0; k != number_of_keys; ++k) {
+        std::string key_str = Key(k);
+        Slice key = key_str;
+        size_t sz = GenerateValue(0 /*value_base*/, value, sizeof(value));
+        Slice v(value, sz);
+        shared->Put(cf_idx, k, 0, true /* pending */);
+
+        if (FLAGS_use_merge) {
+          if (!FLAGS_use_txn) {
+            s = db_->Merge(write_opts, cfh, key, v);
+          } else {
+#ifndef ROCKSDB_LITE
+            Transaction* txn;
+            s = NewTxn(write_opts, &txn);
+            if (s.ok()) {
+              s = txn->Merge(cfh, key, v);
+              if (s.ok()) {
+                s = CommitTxn(txn);
+              }
+            }
+#endif
+          }
+        } else {
+          if (!FLAGS_use_txn) {
+            s = db_->Put(write_opts, cfh, key, v);
+          } else {
+#ifndef ROCKSDB_LITE
+            Transaction* txn;
+            s = NewTxn(write_opts, &txn);
+            if (s.ok()) {
+              s = txn->Put(cfh, key, v);
+              if (s.ok()) {
+                s = CommitTxn(txn);
+              }
+            }
+#endif
+          }
+        }
+
+        shared->Put(cf_idx, k, 0, false /* pending */);
+        if (!s.ok()) {
+          break;
+        }
+      }
+      if (!s.ok()) {
+        break;
+      }
+      ++cf_idx;
+    }
+    if (s.ok()) {
+      s = db_->Flush(FlushOptions(), column_families_);
+    }
+    if (s.ok()) {
+      for (auto cf : column_families_) {
+        delete cf;
+      }
+      column_families_.clear();
+      delete db_;
+      db_ = nullptr;
+#ifndef ROCKSDB_LITE
+      txn_db_ = nullptr;
+#endif
+
+      db_preload_finished_.store(true);
+      auto now = FLAGS_env->NowMicros();
+      fprintf(stdout, "%s Reopening database in read-only\n",
+              FLAGS_env->TimeToString(now / 1000000).c_str());
+      // Reopen as read-only, can ignore all options related to updates
+      Open();
+    } else {
+      fprintf(stderr, "Failed to preload db");
+      exit(1);
+    }
+  }
+
+  Status SetOptions(ThreadState* thread) {
+    assert(FLAGS_set_options_one_in > 0);
+    std::unordered_map<std::string, std::string> opts;
+    std::string name = options_index_[
+      thread->rand.Next() % options_index_.size()];
+    int value_idx = thread->rand.Next() % options_table_[name].size();
+    if (name == "soft_rate_limit" || name == "hard_rate_limit") {
+      opts["soft_rate_limit"] = options_table_["soft_rate_limit"][value_idx];
+      opts["hard_rate_limit"] = options_table_["hard_rate_limit"][value_idx];
+    } else if (name == "level0_file_num_compaction_trigger" ||
+               name == "level0_slowdown_writes_trigger" ||
+               name == "level0_stop_writes_trigger") {
+      opts["level0_file_num_compaction_trigger"] =
+        options_table_["level0_file_num_compaction_trigger"][value_idx];
+      opts["level0_slowdown_writes_trigger"] =
+        options_table_["level0_slowdown_writes_trigger"][value_idx];
+      opts["level0_stop_writes_trigger"] =
+        options_table_["level0_stop_writes_trigger"][value_idx];
+    } else {
+      opts[name] = options_table_[name][value_idx];
+    }
+
+    int rand_cf_idx = thread->rand.Next() % FLAGS_column_families;
+    auto cfh = column_families_[rand_cf_idx];
+    return db_->SetOptions(cfh, opts);
+  }
+
+#ifndef ROCKSDB_LITE
+  Status NewTxn(WriteOptions& write_opts, Transaction** txn) {
+    if (!FLAGS_use_txn) {
+      return Status::InvalidArgument("NewTxn when FLAGS_use_txn is not set");
+    }
+    static std::atomic<uint64_t> txn_id = {0};
+    TransactionOptions txn_options;
+    *txn = txn_db_->BeginTransaction(write_opts, txn_options);
+    auto istr = std::to_string(txn_id.fetch_add(1));
+    Status s = (*txn)->SetName("xid" + istr);
+    return s;
+  }
+
+  Status CommitTxn(Transaction* txn) {
+    if (!FLAGS_use_txn) {
+      return Status::InvalidArgument("CommitTxn when FLAGS_use_txn is not set");
+    }
+    Status s = txn->Prepare();
+    if (s.ok()) {
+      s = txn->Commit();
+    }
+    delete txn;
+    return s;
+  }
+#endif
+
+  virtual void OperateDb(ThreadState* thread) {
+    ReadOptions read_opts(FLAGS_verify_checksum, true);
+    WriteOptions write_opts;
+    auto shared = thread->shared;
+    char value[100];
+    std::string from_db;
+    if (FLAGS_sync) {
+      write_opts.sync = true;
+    }
+    write_opts.disableWAL = FLAGS_disable_wal;
+    const int prefixBound = (int)FLAGS_readpercent + (int)FLAGS_prefixpercent;
+    const int writeBound = prefixBound + (int)FLAGS_writepercent;
+    const int delBound = writeBound + (int)FLAGS_delpercent;
+    const int delRangeBound = delBound + (int)FLAGS_delrangepercent;
+
+    thread->stats.Start();
+    for (uint64_t i = 0; i < FLAGS_ops_per_thread; i++) {
+      if (thread->shared->HasVerificationFailedYet()) {
+        break;
+      }
+      if (i != 0 && (i % (FLAGS_ops_per_thread / (FLAGS_reopen + 1))) == 0) {
+        {
+          thread->stats.FinishedSingleOp();
+          MutexLock l(thread->shared->GetMutex());
+          while (!thread->snapshot_queue.empty()) {
+            db_->ReleaseSnapshot(
+                thread->snapshot_queue.front().second.snapshot);
+            delete thread->snapshot_queue.front().second.key_vec;
+            thread->snapshot_queue.pop();
+          }
+          thread->shared->IncVotedReopen();
+          if (thread->shared->AllVotedReopen()) {
+            thread->shared->GetStressTest()->Reopen();
+            thread->shared->GetCondVar()->SignalAll();
+          } else {
+            thread->shared->GetCondVar()->Wait();
+          }
+          // Commenting this out as we don't want to reset stats on each open.
+          // thread->stats.Start();
+        }
+      }
+
+      // Change Options
+      if (FLAGS_set_options_one_in > 0 &&
+          thread->rand.OneIn(FLAGS_set_options_one_in)) {
+        SetOptions(thread);
+      }
+
+      if (FLAGS_set_in_place_one_in > 0 &&
+          thread->rand.OneIn(FLAGS_set_in_place_one_in)) {
+        options_.inplace_update_support ^= options_.inplace_update_support;
+      }
+
+      MaybeClearOneColumnFamily(thread);
+
+#ifndef ROCKSDB_LITE
+      if (FLAGS_compact_files_one_in > 0 &&
+          thread->rand.Uniform(FLAGS_compact_files_one_in) == 0) {
+        auto* random_cf =
+            column_families_[thread->rand.Next() % FLAGS_column_families];
+        rocksdb::ColumnFamilyMetaData cf_meta_data;
+        db_->GetColumnFamilyMetaData(random_cf, &cf_meta_data);
+
+        // Randomly compact up to three consecutive files from a level
+        const int kMaxRetry = 3;
+        for (int attempt = 0; attempt < kMaxRetry; ++attempt) {
+          size_t random_level = thread->rand.Uniform(
+              static_cast<int>(cf_meta_data.levels.size()));
+
+          const auto& files = cf_meta_data.levels[random_level].files;
+          if (files.size() > 0) {
+            size_t random_file_index =
+                thread->rand.Uniform(static_cast<int>(files.size()));
+            if (files[random_file_index].being_compacted) {
+              // Retry as the selected file is currently being compacted
+              continue;
+            }
+
+            std::vector<std::string> input_files;
+            input_files.push_back(files[random_file_index].name);
+            if (random_file_index > 0 &&
+                !files[random_file_index - 1].being_compacted) {
+              input_files.push_back(files[random_file_index - 1].name);
+            }
+            if (random_file_index + 1 < files.size() &&
+                !files[random_file_index + 1].being_compacted) {
+              input_files.push_back(files[random_file_index + 1].name);
+            }
+
+            size_t output_level =
+                std::min(random_level + 1, cf_meta_data.levels.size() - 1);
+            auto s =
+                db_->CompactFiles(CompactionOptions(), random_cf, input_files,
+                                  static_cast<int>(output_level));
+            if (!s.ok()) {
+              fprintf(stdout, "Unable to perform CompactFiles(): %s\n",
+                      s.ToString().c_str());
+              thread->stats.AddNumCompactFilesFailed(1);
+            } else {
+              thread->stats.AddNumCompactFilesSucceed(1);
+            }
+            break;
+          }
+        }
+      }
+#endif                // !ROCKSDB_LITE
+      int64_t rand_key = GenerateOneKey(thread, i);
+      int rand_column_family = thread->rand.Next() % FLAGS_column_families;
+      std::string keystr = Key(rand_key);
+      Slice key = keystr;
+      std::unique_ptr<MutexLock> lock;
+      if (ShouldAcquireMutexOnKey()) {
+        lock.reset(new MutexLock(
+            shared->GetMutexForKey(rand_column_family, rand_key)));
+      }
+
+      auto column_family = column_families_[rand_column_family];
+
+      if (FLAGS_compact_range_one_in > 0 &&
+          thread->rand.Uniform(FLAGS_compact_range_one_in) == 0) {
+        int64_t end_key_num;
+        if (port::kMaxInt64 - rand_key < FLAGS_compact_range_width) {
+          end_key_num = port::kMaxInt64;
+        } else {
+          end_key_num = FLAGS_compact_range_width + rand_key;
+        }
+        std::string end_key_buf = Key(end_key_num);
+        Slice end_key(end_key_buf);
+
+        CompactRangeOptions cro;
+        cro.exclusive_manual_compaction =
+            static_cast<bool>(thread->rand.Next() % 2);
+        Status status = db_->CompactRange(cro, column_family, &key, &end_key);
+        if (!status.ok()) {
+          printf("Unable to perform CompactRange(): %s\n",
+                 status.ToString().c_str());
+        }
+      }
+
+      std::vector<int> rand_column_families =
+          GenerateColumnFamilies(FLAGS_column_families, rand_column_family);
+
+      if (FLAGS_flush_one_in > 0 &&
+          thread->rand.Uniform(FLAGS_flush_one_in) == 0) {
+        FlushOptions flush_opts;
+        std::vector<ColumnFamilyHandle*> cfhs;
+        std::for_each(
+            rand_column_families.begin(), rand_column_families.end(),
+            [this, &cfhs](int k) { cfhs.push_back(column_families_[k]); });
+        Status status = db_->Flush(flush_opts, cfhs);
+        if (!status.ok()) {
+          fprintf(stdout, "Unable to perform Flush(): %s\n",
+                  status.ToString().c_str());
+        }
+      }
+
+      std::vector<int64_t> rand_keys = GenerateKeys(rand_key);
+
+      if (FLAGS_ingest_external_file_one_in > 0 &&
+          thread->rand.Uniform(FLAGS_ingest_external_file_one_in) == 0) {
+        TestIngestExternalFile(thread, rand_column_families, rand_keys, lock);
+      }
+
+      if (FLAGS_backup_one_in > 0 &&
+          thread->rand.Uniform(FLAGS_backup_one_in) == 0) {
+        Status s = TestBackupRestore(thread, rand_column_families, rand_keys);
+        if (!s.ok()) {
+          VerificationAbort(shared, "Backup/restore gave inconsistent state",
+                            s);
+        }
+      }
+
+      if (FLAGS_checkpoint_one_in > 0 &&
+          thread->rand.Uniform(FLAGS_checkpoint_one_in) == 0) {
+        Status s = TestCheckpoint(thread, rand_column_families, rand_keys);
+        if (!s.ok()) {
+          VerificationAbort(shared, "Checkpoint gave inconsistent state", s);
+        }
+      }
+
+      if (FLAGS_acquire_snapshot_one_in > 0 &&
+          thread->rand.Uniform(FLAGS_acquire_snapshot_one_in) == 0) {
+        auto snapshot = db_->GetSnapshot();
+        ReadOptions ropt;
+        ropt.snapshot = snapshot;
+        std::string value_at;
+        // When taking a snapshot, we also read a key from that snapshot. We
+        // will later read the same key before releasing the snapshot and verify
+        // that the results are the same.
+        auto status_at = db_->Get(ropt, column_family, key, &value_at);
+        std::vector<bool> *key_vec = nullptr;
+
+        if (FLAGS_compare_full_db_state_snapshot &&
+            (thread->tid == 0)) {
+          key_vec = new std::vector<bool>(FLAGS_max_key);
+          // When `prefix_extractor` is set, seeking to beginning and scanning
+          // across prefixes are only supported with `total_order_seek` set.
+          ropt.total_order_seek = true;
+          std::unique_ptr<Iterator> iterator(db_->NewIterator(ropt));
+          for (iterator->SeekToFirst(); iterator->Valid(); iterator->Next()) {
+            uint64_t key_val;
+            if (GetIntVal(iterator->key().ToString(), &key_val)) {
+              (*key_vec)[key_val] = true;
+            }
+          }
+        }
+
+        ThreadState::SnapshotState snap_state = {
+            snapshot, rand_column_family, column_family->GetName(),
+            keystr,   status_at,          value_at, key_vec};
+        thread->snapshot_queue.emplace(
+            std::min(FLAGS_ops_per_thread - 1, i + FLAGS_snapshot_hold_ops),
+            snap_state);
+      }
+      while (!thread->snapshot_queue.empty() &&
+          i == thread->snapshot_queue.front().first) {
+        auto snap_state = thread->snapshot_queue.front().second;
+        assert(snap_state.snapshot);
+        // Note: this is unsafe as the cf might be dropped concurrently. But it
+        // is ok since unclean cf drop is cunnrently not supported by write
+        // prepared transactions.
+        Status s =
+            AssertSame(db_, column_families_[snap_state.cf_at], snap_state);
+        if (!s.ok()) {
+          VerificationAbort(shared, "Snapshot gave inconsistent state", s);
+        }
+        db_->ReleaseSnapshot(snap_state.snapshot);
+        delete snap_state.key_vec;
+        thread->snapshot_queue.pop();
+      }
+
+      int prob_op = thread->rand.Uniform(100);
+      if (prob_op >= 0 && prob_op < (int)FLAGS_readpercent) {
+        // OPERATION read
+        TestGet(thread, read_opts, rand_column_families, rand_keys);
+      } else if ((int)FLAGS_readpercent <= prob_op && prob_op < prefixBound) {
+        // OPERATION prefix scan
+        // keys are 8 bytes long, prefix size is FLAGS_prefix_size. There are
+        // (8 - FLAGS_prefix_size) bytes besides the prefix. So there will
+        // be 2 ^ ((8 - FLAGS_prefix_size) * 8) possible keys with the same
+        // prefix
+        TestPrefixScan(thread, read_opts, rand_column_families, rand_keys);
+      } else if (prefixBound <= prob_op && prob_op < writeBound) {
+        // OPERATION write
+        TestPut(thread, write_opts, read_opts, rand_column_families, rand_keys,
+                value, lock);
+      } else if (writeBound <= prob_op && prob_op < delBound) {
+        // OPERATION delete
+        TestDelete(thread, write_opts, rand_column_families, rand_keys, lock);
+      } else if (delBound <= prob_op && prob_op < delRangeBound) {
+        // OPERATION delete range
+        TestDeleteRange(thread, write_opts, rand_column_families, rand_keys,
+                        lock);
+      } else {
+        // OPERATION iterate
+        TestIterate(thread, read_opts, rand_column_families, rand_keys);
+      }
+      thread->stats.FinishedSingleOp();
+    }
+
+    thread->stats.Stop();
+  }
+
+  virtual void VerifyDb(ThreadState* thread) const = 0;
+
+  virtual void MaybeClearOneColumnFamily(ThreadState* /* thread */) {}
+
+  virtual bool ShouldAcquireMutexOnKey() const { return false; }
+
+  virtual std::vector<int> GenerateColumnFamilies(
+      const int /* num_column_families */, int rand_column_family) const {
+    return {rand_column_family};
+  }
+
+  virtual std::vector<int64_t> GenerateKeys(int64_t rand_key) const {
+    return {rand_key};
+  }
+
+  virtual Status TestGet(ThreadState* thread,
+      const ReadOptions& read_opts,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys) = 0;
+
+  virtual Status TestPrefixScan(ThreadState* thread,
+      const ReadOptions& read_opts,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys) = 0;
+
+  virtual Status TestPut(ThreadState* thread,
+      WriteOptions& write_opts, const ReadOptions& read_opts,
+      const std::vector<int>& cf_ids, const std::vector<int64_t>& keys,
+      char (&value)[100], std::unique_ptr<MutexLock>& lock) = 0;
+
+  virtual Status TestDelete(ThreadState* thread, WriteOptions& write_opts,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys,
+      std::unique_ptr<MutexLock>& lock) = 0;
+
+  virtual Status TestDeleteRange(ThreadState* thread,
+      WriteOptions& write_opts,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys,
+      std::unique_ptr<MutexLock>& lock) = 0;
+
+  virtual void TestIngestExternalFile(
+      ThreadState* thread, const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys,
+      std::unique_ptr<MutexLock>& lock) = 0;
+
+  // Given a key K, this creates an iterator which scans to K and then
+  // does a random sequence of Next/Prev operations.
+  virtual Status TestIterate(ThreadState* thread,
+      const ReadOptions& read_opts,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys) {
+    Status s;
+    const Snapshot* snapshot = db_->GetSnapshot();
+    ReadOptions readoptionscopy = read_opts;
+    readoptionscopy.snapshot = snapshot;
+
+    std::string upper_bound_str;
+    Slice upper_bound;
+    if (thread->rand.OneIn(16)) {
+      // in 1/16 chance, set a iterator upper bound
+      int64_t rand_upper_key = GenerateOneKey(thread, FLAGS_ops_per_thread);
+      upper_bound_str = Key(rand_upper_key);
+      upper_bound = Slice(upper_bound_str);
+      // uppder_bound can be smaller than seek key, but the query itself
+      // should not crash either.
+      readoptionscopy.iterate_upper_bound = &upper_bound;
+    }
+    std::string lower_bound_str;
+    Slice lower_bound;
+    if (thread->rand.OneIn(16)) {
+      // in 1/16 chance, set a iterator lower bound
+      int64_t rand_lower_key = GenerateOneKey(thread, FLAGS_ops_per_thread);
+      lower_bound_str = Key(rand_lower_key);
+      lower_bound = Slice(lower_bound_str);
+      // uppder_bound can be smaller than seek key, but the query itself
+      // should not crash either.
+      readoptionscopy.iterate_lower_bound = &lower_bound;
+    }
+
+    auto cfh = column_families_[rand_column_families[0]];
+    std::unique_ptr<Iterator> iter(db_->NewIterator(readoptionscopy, cfh));
+
+    std::string key_str = Key(rand_keys[0]);
+    Slice key = key_str;
+    iter->Seek(key);
+    for (uint64_t i = 0; i < FLAGS_num_iterations && iter->Valid(); i++) {
+      if (thread->rand.OneIn(2)) {
+        iter->Next();
+      } else {
+        iter->Prev();
+      }
+    }
+
+    if (s.ok()) {
+      thread->stats.AddIterations(1);
+    } else {
+      thread->stats.AddErrors(1);
+    }
+
+    db_->ReleaseSnapshot(snapshot);
+
+    return s;
+  }
+
+#ifdef ROCKSDB_LITE
+  virtual Status TestBackupRestore(
+      ThreadState* /* thread */,
+      const std::vector<int>& /* rand_column_families */,
+      const std::vector<int64_t>& /* rand_keys */) {
+    assert(false);
+    fprintf(stderr,
+            "RocksDB lite does not support "
+            "TestBackupRestore\n");
+    std::terminate();
+  }
+
+  virtual Status TestCheckpoint(
+      ThreadState* /* thread */,
+      const std::vector<int>& /* rand_column_families */,
+      const std::vector<int64_t>& /* rand_keys */) {
+    assert(false);
+    fprintf(stderr,
+            "RocksDB lite does not support "
+            "TestCheckpoint\n");
+    std::terminate();
+  }
+#else  // ROCKSDB_LITE
+  virtual Status TestBackupRestore(ThreadState* thread,
+                                   const std::vector<int>& rand_column_families,
+                                   const std::vector<int64_t>& rand_keys) {
+    // Note the column families chosen by `rand_column_families` cannot be
+    // dropped while the locks for `rand_keys` are held. So we should not have
+    // to worry about accessing those column families throughout this function.
+    assert(rand_column_families.size() == rand_keys.size());
+    std::string backup_dir = FLAGS_db + "/.backup" + ToString(thread->tid);
+    std::string restore_dir = FLAGS_db + "/.restore" + ToString(thread->tid);
+    BackupableDBOptions backup_opts(backup_dir);
+    BackupEngine* backup_engine = nullptr;
+    Status s = BackupEngine::Open(FLAGS_env, backup_opts, &backup_engine);
+    if (s.ok()) {
+      s = backup_engine->CreateNewBackup(db_);
+    }
+    if (s.ok()) {
+      delete backup_engine;
+      backup_engine = nullptr;
+      s = BackupEngine::Open(FLAGS_env, backup_opts, &backup_engine);
+    }
+    if (s.ok()) {
+      s = backup_engine->RestoreDBFromLatestBackup(restore_dir /* db_dir */,
+                                                   restore_dir /* wal_dir */);
+    }
+    if (s.ok()) {
+      s = backup_engine->PurgeOldBackups(0 /* num_backups_to_keep */);
+    }
+    DB* restored_db = nullptr;
+    std::vector<ColumnFamilyHandle*> restored_cf_handles;
+    if (s.ok()) {
+      Options restore_options(options_);
+      restore_options.listeners.clear();
+      std::vector<ColumnFamilyDescriptor> cf_descriptors;
+      // TODO(ajkr): `column_family_names_` is not safe to access here when
+      // `clear_column_family_one_in != 0`. But we can't easily switch to
+      // `ListColumnFamilies` to get names because it won't necessarily give
+      // the same order as `column_family_names_`.
+      assert(FLAGS_clear_column_family_one_in == 0);
+      for (auto name : column_family_names_) {
+        cf_descriptors.emplace_back(name, ColumnFamilyOptions(restore_options));
+      }
+      s = DB::Open(DBOptions(restore_options), restore_dir, cf_descriptors,
+                   &restored_cf_handles, &restored_db);
+    }
+    // for simplicity, currently only verifies existence/non-existence of a few
+    // keys
+    for (size_t i = 0; s.ok() && i < rand_column_families.size(); ++i) {
+      std::string key_str = Key(rand_keys[i]);
+      Slice key = key_str;
+      std::string restored_value;
+      Status get_status = restored_db->Get(
+          ReadOptions(), restored_cf_handles[rand_column_families[i]], key,
+          &restored_value);
+      bool exists =
+          thread->shared->Exists(rand_column_families[i], rand_keys[i]);
+      if (get_status.ok()) {
+        if (!exists) {
+          s = Status::Corruption(
+              "key exists in restore but not in original db");
+        }
+      } else if (get_status.IsNotFound()) {
+        if (exists) {
+          s = Status::Corruption(
+              "key exists in original db but not in restore");
+        }
+      } else {
+        s = get_status;
+      }
+    }
+    if (backup_engine != nullptr) {
+      delete backup_engine;
+      backup_engine = nullptr;
+    }
+    if (restored_db != nullptr) {
+      for (auto* cf_handle : restored_cf_handles) {
+        restored_db->DestroyColumnFamilyHandle(cf_handle);
+      }
+      delete restored_db;
+      restored_db = nullptr;
+    }
+    if (!s.ok()) {
+      printf("A backup/restore operation failed with: %s\n",
+             s.ToString().c_str());
+    }
+    return s;
+  }
+
+  virtual Status TestCheckpoint(ThreadState* thread,
+                                const std::vector<int>& rand_column_families,
+                                const std::vector<int64_t>& rand_keys) {
+    // Note the column families chosen by `rand_column_families` cannot be
+    // dropped while the locks for `rand_keys` are held. So we should not have
+    // to worry about accessing those column families throughout this function.
+    assert(rand_column_families.size() == rand_keys.size());
+    std::string checkpoint_dir =
+        FLAGS_db + "/.checkpoint" + ToString(thread->tid);
+    DestroyDB(checkpoint_dir, Options());
+    Checkpoint* checkpoint = nullptr;
+    Status s = Checkpoint::Create(db_, &checkpoint);
+    if (s.ok()) {
+      s = checkpoint->CreateCheckpoint(checkpoint_dir);
+    }
+    std::vector<ColumnFamilyHandle*> cf_handles;
+    DB* checkpoint_db = nullptr;
+    if (s.ok()) {
+      delete checkpoint;
+      checkpoint = nullptr;
+      Options options(options_);
+      options.listeners.clear();
+      std::vector<ColumnFamilyDescriptor> cf_descs;
+      // TODO(ajkr): `column_family_names_` is not safe to access here when
+      // `clear_column_family_one_in != 0`. But we can't easily switch to
+      // `ListColumnFamilies` to get names because it won't necessarily give
+      // the same order as `column_family_names_`.
+      if (FLAGS_clear_column_family_one_in == 0) {
+        for (const auto& name : column_family_names_) {
+          cf_descs.emplace_back(name, ColumnFamilyOptions(options));
+        }
+        s = DB::OpenForReadOnly(DBOptions(options), checkpoint_dir, cf_descs,
+                                &cf_handles, &checkpoint_db);
+      }
+    }
+    if (checkpoint_db != nullptr) {
+      for (size_t i = 0; s.ok() && i < rand_column_families.size(); ++i) {
+        std::string key_str = Key(rand_keys[i]);
+        Slice key = key_str;
+        std::string value;
+        Status get_status = checkpoint_db->Get(
+            ReadOptions(), cf_handles[rand_column_families[i]], key, &value);
+        bool exists =
+            thread->shared->Exists(rand_column_families[i], rand_keys[i]);
+        if (get_status.ok()) {
+          if (!exists) {
+            s = Status::Corruption(
+                "key exists in checkpoint but not in original db");
+          }
+        } else if (get_status.IsNotFound()) {
+          if (exists) {
+            s = Status::Corruption(
+                "key exists in original db but not in checkpoint");
+          }
+        } else {
+          s = get_status;
+        }
+      }
+      for (auto cfh : cf_handles) {
+        delete cfh;
+      }
+      cf_handles.clear();
+      delete checkpoint_db;
+      checkpoint_db = nullptr;
+    }
+    DestroyDB(checkpoint_dir, Options());
+    if (!s.ok()) {
+      fprintf(stderr, "A checkpoint operation failed with: %s\n",
+              s.ToString().c_str());
+    }
+    return s;
+  }
+#endif  // ROCKSDB_LITE
+
+  void VerificationAbort(SharedState* shared, std::string msg, Status s) const {
+    printf("Verification failed: %s. Status is %s\n", msg.c_str(),
+           s.ToString().c_str());
+    shared->SetVerificationFailure();
+  }
+
+  void VerificationAbort(SharedState* shared, std::string msg, int cf,
+                         int64_t key) const {
+    printf("Verification failed for column family %d key %" PRIi64 ": %s\n", cf, key,
+           msg.c_str());
+    shared->SetVerificationFailure();
+  }
+
+  void PrintEnv() const {
+    fprintf(stdout, "RocksDB version           : %d.%d\n", kMajorVersion,
+            kMinorVersion);
+    fprintf(stdout, "Format version            : %d\n", FLAGS_format_version);
+    fprintf(stdout, "TransactionDB             : %s\n",
+            FLAGS_use_txn ? "true" : "false");
+    fprintf(stdout, "Read only mode            : %s\n",
+            FLAGS_read_only ? "true" : "false");
+    fprintf(stdout, "Atomic flush              : %s\n",
+            FLAGS_atomic_flush ? "true" : "false");
+    fprintf(stdout, "Column families           : %d\n", FLAGS_column_families);
+    if (!FLAGS_test_batches_snapshots) {
+      fprintf(stdout, "Clear CFs one in          : %d\n",
+              FLAGS_clear_column_family_one_in);
+    }
+    fprintf(stdout, "Number of threads         : %d\n", FLAGS_threads);
+    fprintf(stdout, "Ops per thread            : %lu\n",
+            (unsigned long)FLAGS_ops_per_thread);
+    std::string ttl_state("unused");
+    if (FLAGS_ttl > 0) {
+      ttl_state = NumberToString(FLAGS_ttl);
+    }
+    fprintf(stdout, "Time to live(sec)         : %s\n", ttl_state.c_str());
+    fprintf(stdout, "Read percentage           : %d%%\n", FLAGS_readpercent);
+    fprintf(stdout, "Prefix percentage         : %d%%\n", FLAGS_prefixpercent);
+    fprintf(stdout, "Write percentage          : %d%%\n", FLAGS_writepercent);
+    fprintf(stdout, "Delete percentage         : %d%%\n", FLAGS_delpercent);
+    fprintf(stdout, "Delete range percentage   : %d%%\n", FLAGS_delrangepercent);
+    fprintf(stdout, "No overwrite percentage   : %d%%\n",
+            FLAGS_nooverwritepercent);
+    fprintf(stdout, "Iterate percentage        : %d%%\n", FLAGS_iterpercent);
+    fprintf(stdout, "DB-write-buffer-size      : %" PRIu64 "\n",
+            FLAGS_db_write_buffer_size);
+    fprintf(stdout, "Write-buffer-size         : %d\n",
+            FLAGS_write_buffer_size);
+    fprintf(stdout, "Iterations                : %lu\n",
+            (unsigned long)FLAGS_num_iterations);
+    fprintf(stdout, "Max key                   : %lu\n",
+            (unsigned long)FLAGS_max_key);
+    fprintf(stdout, "Ratio #ops/#keys          : %f\n",
+            (1.0 * FLAGS_ops_per_thread * FLAGS_threads) / FLAGS_max_key);
+    fprintf(stdout, "Num times DB reopens      : %d\n", FLAGS_reopen);
+    fprintf(stdout, "Batches/snapshots         : %d\n",
+            FLAGS_test_batches_snapshots);
+    fprintf(stdout, "Do update in place        : %d\n", FLAGS_in_place_update);
+    fprintf(stdout, "Num keys per lock         : %d\n",
+            1 << FLAGS_log2_keys_per_lock);
+    std::string compression = CompressionTypeToString(FLAGS_compression_type_e);
+    fprintf(stdout, "Compression               : %s\n", compression.c_str());
+    std::string checksum = ChecksumTypeToString(FLAGS_checksum_type_e);
+    fprintf(stdout, "Checksum type             : %s\n", checksum.c_str());
+    fprintf(stdout, "Max subcompactions        : %" PRIu64 "\n",
+            FLAGS_subcompactions);
+
+    const char* memtablerep = "";
+    switch (FLAGS_rep_factory) {
+      case kSkipList:
+        memtablerep = "skip_list";
+        break;
+      case kHashSkipList:
+        memtablerep = "prefix_hash";
+        break;
+      case kVectorRep:
+        memtablerep = "vector";
+        break;
+    }
+
+    fprintf(stdout, "Memtablerep               : %s\n", memtablerep);
+
+    fprintf(stdout, "Test kill odd             : %d\n", rocksdb_kill_odds);
+    if (!rocksdb_kill_prefix_blacklist.empty()) {
+      fprintf(stdout, "Skipping kill points prefixes:\n");
+      for (auto& p : rocksdb_kill_prefix_blacklist) {
+        fprintf(stdout, "  %s\n", p.c_str());
+      }
+    }
+
+    fprintf(stdout, "------------------------------------------------\n");
+  }
+
+  void Open() {
+    assert(db_ == nullptr);
+#ifndef ROCKSDB_LITE
+    assert(txn_db_ == nullptr);
+#endif
+    if (FLAGS_options_file.empty()) {
+      BlockBasedTableOptions block_based_options;
+      block_based_options.block_cache = cache_;
+      block_based_options.block_cache_compressed = compressed_cache_;
+      block_based_options.checksum = FLAGS_checksum_type_e;
+      block_based_options.block_size = FLAGS_block_size;
+      block_based_options.format_version =
+          static_cast<uint32_t>(FLAGS_format_version);
+      block_based_options.index_block_restart_interval =
+          static_cast<int32_t>(FLAGS_index_block_restart_interval);
+      block_based_options.filter_policy = filter_policy_;
+      options_.table_factory.reset(
+          NewBlockBasedTableFactory(block_based_options));
+      options_.db_write_buffer_size = FLAGS_db_write_buffer_size;
+      options_.write_buffer_size = FLAGS_write_buffer_size;
+      options_.max_write_buffer_number = FLAGS_max_write_buffer_number;
+      options_.min_write_buffer_number_to_merge =
+          FLAGS_min_write_buffer_number_to_merge;
+      options_.max_write_buffer_number_to_maintain =
+          FLAGS_max_write_buffer_number_to_maintain;
+      options_.memtable_prefix_bloom_size_ratio =
+          FLAGS_memtable_prefix_bloom_size_ratio;
+      options_.memtable_whole_key_filtering =
+          FLAGS_memtable_whole_key_filtering;
+      options_.max_background_compactions = FLAGS_max_background_compactions;
+      options_.max_background_flushes = FLAGS_max_background_flushes;
+      options_.compaction_style =
+          static_cast<rocksdb::CompactionStyle>(FLAGS_compaction_style);
+      options_.prefix_extractor.reset(
+          NewFixedPrefixTransform(FLAGS_prefix_size));
+      options_.max_open_files = FLAGS_open_files;
+      options_.statistics = dbstats;
+      options_.env = FLAGS_env;
+      options_.use_fsync = FLAGS_use_fsync;
+      options_.compaction_readahead_size = FLAGS_compaction_readahead_size;
+      options_.allow_mmap_reads = FLAGS_mmap_read;
+      options_.allow_mmap_writes = FLAGS_mmap_write;
+      options_.use_direct_reads = FLAGS_use_direct_reads;
+      options_.use_direct_io_for_flush_and_compaction =
+          FLAGS_use_direct_io_for_flush_and_compaction;
+      options_.recycle_log_file_num =
+          static_cast<size_t>(FLAGS_recycle_log_file_num);
+      options_.target_file_size_base = FLAGS_target_file_size_base;
+      options_.target_file_size_multiplier = FLAGS_target_file_size_multiplier;
+      options_.max_bytes_for_level_base = FLAGS_max_bytes_for_level_base;
+      options_.max_bytes_for_level_multiplier =
+          FLAGS_max_bytes_for_level_multiplier;
+      options_.level0_stop_writes_trigger = FLAGS_level0_stop_writes_trigger;
+      options_.level0_slowdown_writes_trigger =
+          FLAGS_level0_slowdown_writes_trigger;
+      options_.level0_file_num_compaction_trigger =
+          FLAGS_level0_file_num_compaction_trigger;
+      options_.compression = FLAGS_compression_type_e;
+      options_.compression_opts.max_dict_bytes =
+          FLAGS_compression_max_dict_bytes;
+      options_.compression_opts.zstd_max_train_bytes =
+          FLAGS_compression_zstd_max_train_bytes;
+      options_.create_if_missing = true;
+      options_.max_manifest_file_size = FLAGS_max_manifest_file_size;
+      options_.inplace_update_support = FLAGS_in_place_update;
+      options_.max_subcompactions = static_cast<uint32_t>(FLAGS_subcompactions);
+      options_.allow_concurrent_memtable_write =
+          FLAGS_allow_concurrent_memtable_write;
+      options_.enable_pipelined_write = FLAGS_enable_pipelined_write;
+      options_.enable_write_thread_adaptive_yield =
+          FLAGS_enable_write_thread_adaptive_yield;
+      options_.compaction_options_universal.size_ratio =
+          FLAGS_universal_size_ratio;
+      options_.compaction_options_universal.min_merge_width =
+          FLAGS_universal_min_merge_width;
+      options_.compaction_options_universal.max_merge_width =
+          FLAGS_universal_max_merge_width;
+      options_.compaction_options_universal.max_size_amplification_percent =
+          FLAGS_universal_max_size_amplification_percent;
+      options_.atomic_flush = FLAGS_atomic_flush;
+    } else {
+#ifdef ROCKSDB_LITE
+      fprintf(stderr, "--options_file not supported in lite mode\n");
+      exit(1);
+#else
+      DBOptions db_options;
+      std::vector<ColumnFamilyDescriptor> cf_descriptors;
+      Status s = LoadOptionsFromFile(FLAGS_options_file, Env::Default(),
+                                     &db_options, &cf_descriptors);
+      if (!s.ok()) {
+        fprintf(stderr, "Unable to load options file %s --- %s\n",
+                FLAGS_options_file.c_str(), s.ToString().c_str());
+        exit(1);
+      }
+      options_ = Options(db_options, cf_descriptors[0].options);
+#endif  // ROCKSDB_LITE
+    }
+
+    if (FLAGS_rate_limiter_bytes_per_sec > 0) {
+      options_.rate_limiter.reset(NewGenericRateLimiter(
+          FLAGS_rate_limiter_bytes_per_sec, 1000 /* refill_period_us */,
+          10 /* fairness */,
+          FLAGS_rate_limit_bg_reads ? RateLimiter::Mode::kReadsOnly
+                                    : RateLimiter::Mode::kWritesOnly));
+      if (FLAGS_rate_limit_bg_reads) {
+        options_.new_table_reader_for_compaction_inputs = true;
+      }
+    }
+
+    if (FLAGS_prefix_size == 0 && FLAGS_rep_factory == kHashSkipList) {
+      fprintf(stderr,
+              "prefeix_size cannot be zero if memtablerep == prefix_hash\n");
+      exit(1);
+    }
+    if (FLAGS_prefix_size != 0 && FLAGS_rep_factory != kHashSkipList) {
+      fprintf(stderr,
+              "WARNING: prefix_size is non-zero but "
+              "memtablerep != prefix_hash\n");
+    }
+    switch (FLAGS_rep_factory) {
+      case kSkipList:
+        // no need to do anything
+        break;
+#ifndef ROCKSDB_LITE
+      case kHashSkipList:
+        options_.memtable_factory.reset(NewHashSkipListRepFactory(10000));
+        break;
+      case kVectorRep:
+        options_.memtable_factory.reset(new VectorRepFactory());
+        break;
+#else
+      default:
+        fprintf(stderr,
+                "RocksdbLite only supports skip list mem table. Skip "
+                "--rep_factory\n");
+#endif  // ROCKSDB_LITE
+    }
+
+    if (FLAGS_use_full_merge_v1) {
+      options_.merge_operator = MergeOperators::CreateDeprecatedPutOperator();
+    } else {
+      options_.merge_operator = MergeOperators::CreatePutOperator();
+    }
+
+    fprintf(stdout, "DB path: [%s]\n", FLAGS_db.c_str());
+
+    Status s;
+    if (FLAGS_ttl == -1) {
+      std::vector<std::string> existing_column_families;
+      s = DB::ListColumnFamilies(DBOptions(options_), FLAGS_db,
+                                 &existing_column_families);  // ignore errors
+      if (!s.ok()) {
+        // DB doesn't exist
+        assert(existing_column_families.empty());
+        assert(column_family_names_.empty());
+        column_family_names_.push_back(kDefaultColumnFamilyName);
+      } else if (column_family_names_.empty()) {
+        // this is the first call to the function Open()
+        column_family_names_ = existing_column_families;
+      } else {
+        // this is a reopen. just assert that existing column_family_names are
+        // equivalent to what we remember
+        auto sorted_cfn = column_family_names_;
+        std::sort(sorted_cfn.begin(), sorted_cfn.end());
+        std::sort(existing_column_families.begin(),
+                  existing_column_families.end());
+        if (sorted_cfn != existing_column_families) {
+          fprintf(stderr,
+                  "Expected column families differ from the existing:\n");
+          printf("Expected: {");
+          for (auto cf : sorted_cfn) {
+            printf("%s ", cf.c_str());
+          }
+          printf("}\n");
+          printf("Existing: {");
+          for (auto cf : existing_column_families) {
+            printf("%s ", cf.c_str());
+          }
+          printf("}\n");
+        }
+        assert(sorted_cfn == existing_column_families);
+      }
+      std::vector<ColumnFamilyDescriptor> cf_descriptors;
+      for (auto name : column_family_names_) {
+        if (name != kDefaultColumnFamilyName) {
+          new_column_family_name_ =
+              std::max(new_column_family_name_.load(), std::stoi(name) + 1);
+        }
+        cf_descriptors.emplace_back(name, ColumnFamilyOptions(options_));
+      }
+      while (cf_descriptors.size() < (size_t)FLAGS_column_families) {
+        std::string name = ToString(new_column_family_name_.load());
+        new_column_family_name_++;
+        cf_descriptors.emplace_back(name, ColumnFamilyOptions(options_));
+        column_family_names_.push_back(name);
+      }
+      options_.listeners.clear();
+      options_.listeners.emplace_back(
+          new DbStressListener(FLAGS_db, options_.db_paths, cf_descriptors));
+      options_.create_missing_column_families = true;
+      if (!FLAGS_use_txn) {
+        if (db_preload_finished_.load() && FLAGS_read_only) {
+          s = DB::OpenForReadOnly(DBOptions(options_), FLAGS_db, cf_descriptors,
+                                  &column_families_, &db_);
+        } else {
+          s = DB::Open(DBOptions(options_), FLAGS_db, cf_descriptors,
+                       &column_families_, &db_);
+        }
+      } else {
+#ifndef ROCKSDB_LITE
+        TransactionDBOptions txn_db_options;
+        // For the moment it is sufficient to test WRITE_PREPARED policy
+        txn_db_options.write_policy = TxnDBWritePolicy::WRITE_PREPARED;
+        s = TransactionDB::Open(options_, txn_db_options, FLAGS_db,
+                                cf_descriptors, &column_families_, &txn_db_);
+        db_ = txn_db_;
+        // after a crash, rollback to commit recovered transactions
+        std::vector<Transaction*> trans;
+        txn_db_->GetAllPreparedTransactions(&trans);
+        Random rand(static_cast<uint32_t>(FLAGS_seed));
+        for (auto txn : trans) {
+          if (rand.OneIn(2)) {
+            s = txn->Commit();
+            assert(s.ok());
+          } else {
+            s = txn->Rollback();
+            assert(s.ok());
+          }
+          delete txn;
+        }
+        trans.clear();
+        txn_db_->GetAllPreparedTransactions(&trans);
+        assert(trans.size() == 0);
+#endif
+      }
+      assert(!s.ok() || column_families_.size() ==
+                            static_cast<size_t>(FLAGS_column_families));
+    } else {
+#ifndef ROCKSDB_LITE
+      DBWithTTL* db_with_ttl;
+      s = DBWithTTL::Open(options_, FLAGS_db, &db_with_ttl, FLAGS_ttl);
+      db_ = db_with_ttl;
+#else
+      fprintf(stderr, "TTL is not supported in RocksDBLite\n");
+      exit(1);
+#endif
+    }
+    if (!s.ok()) {
+      fprintf(stderr, "open error: %s\n", s.ToString().c_str());
+      exit(1);
+    }
+  }
+
+  void Reopen() {
+    for (auto cf : column_families_) {
+      delete cf;
+    }
+    column_families_.clear();
+    delete db_;
+    db_ = nullptr;
+#ifndef ROCKSDB_LITE
+    txn_db_ = nullptr;
+#endif
+
+    num_times_reopened_++;
+    auto now = FLAGS_env->NowMicros();
+    fprintf(stdout, "%s Reopening database for the %dth time\n",
+            FLAGS_env->TimeToString(now/1000000).c_str(),
+            num_times_reopened_);
+    Open();
+  }
+
+  void PrintStatistics() {
+    if (dbstats) {
+      fprintf(stdout, "STATISTICS:\n%s\n", dbstats->ToString().c_str());
+    }
+  }
+
+  std::shared_ptr<Cache> cache_;
+  std::shared_ptr<Cache> compressed_cache_;
+  std::shared_ptr<const FilterPolicy> filter_policy_;
+  DB* db_;
+#ifndef ROCKSDB_LITE
+  TransactionDB* txn_db_;
+#endif
+  Options options_;
+  std::vector<ColumnFamilyHandle*> column_families_;
+  std::vector<std::string> column_family_names_;
+  std::atomic<int> new_column_family_name_;
+  int num_times_reopened_;
+  std::unordered_map<std::string, std::vector<std::string>> options_table_;
+  std::vector<std::string> options_index_;
+  std::atomic<bool> db_preload_finished_;
+};
+
+class NonBatchedOpsStressTest : public StressTest {
+ public:
+  NonBatchedOpsStressTest() {}
+
+  virtual ~NonBatchedOpsStressTest() {}
+
+  virtual void VerifyDb(ThreadState* thread) const {
+    ReadOptions options(FLAGS_verify_checksum, true);
+    auto shared = thread->shared;
+    const int64_t max_key = shared->GetMaxKey();
+    const int64_t keys_per_thread = max_key / shared->GetNumThreads();
+    int64_t start = keys_per_thread * thread->tid;
+    int64_t end = start + keys_per_thread;
+    if (thread->tid == shared->GetNumThreads() - 1) {
+      end = max_key;
+    }
+    for (size_t cf = 0; cf < column_families_.size(); ++cf) {
+      if (thread->shared->HasVerificationFailedYet()) {
+        break;
+      }
+      if (!thread->rand.OneIn(2)) {
+        // Use iterator to verify this range
+        std::unique_ptr<Iterator> iter(
+            db_->NewIterator(options, column_families_[cf]));
+        iter->Seek(Key(start));
+        for (auto i = start; i < end; i++) {
+          if (thread->shared->HasVerificationFailedYet()) {
+            break;
+          }
+          // TODO(ljin): update "long" to uint64_t
+          // Reseek when the prefix changes
+          if (i % (static_cast<int64_t>(1) << 8 * (8 - FLAGS_prefix_size)) ==
+              0) {
+            iter->Seek(Key(i));
+          }
+          std::string from_db;
+          std::string keystr = Key(i);
+          Slice k = keystr;
+          Status s = iter->status();
+          if (iter->Valid()) {
+            if (iter->key().compare(k) > 0) {
+              s = Status::NotFound(Slice());
+            } else if (iter->key().compare(k) == 0) {
+              from_db = iter->value().ToString();
+              iter->Next();
+            } else if (iter->key().compare(k) < 0) {
+              VerificationAbort(shared, "An out of range key was found",
+                                static_cast<int>(cf), i);
+            }
+          } else {
+            // The iterator found no value for the key in question, so do not
+            // move to the next item in the iterator
+            s = Status::NotFound(Slice());
+          }
+          VerifyValue(static_cast<int>(cf), i, options, shared, from_db, s,
+                      true);
+          if (from_db.length()) {
+            PrintKeyValue(static_cast<int>(cf), static_cast<uint32_t>(i),
+                          from_db.data(), from_db.length());
+          }
+        }
+      } else {
+        // Use Get to verify this range
+        for (auto i = start; i < end; i++) {
+          if (thread->shared->HasVerificationFailedYet()) {
+            break;
+          }
+          std::string from_db;
+          std::string keystr = Key(i);
+          Slice k = keystr;
+          Status s = db_->Get(options, column_families_[cf], k, &from_db);
+          VerifyValue(static_cast<int>(cf), i, options, shared, from_db, s,
+                      true);
+          if (from_db.length()) {
+            PrintKeyValue(static_cast<int>(cf), static_cast<uint32_t>(i),
+                          from_db.data(), from_db.length());
+          }
+        }
+      }
+    }
+  }
+
+  virtual void MaybeClearOneColumnFamily(ThreadState* thread) {
+    if (FLAGS_clear_column_family_one_in != 0 && FLAGS_column_families > 1) {
+      if (thread->rand.OneIn(FLAGS_clear_column_family_one_in)) {
+        // drop column family and then create it again (can't drop default)
+        int cf = thread->rand.Next() % (FLAGS_column_families - 1) + 1;
+        std::string new_name =
+            ToString(new_column_family_name_.fetch_add(1));
+        {
+          MutexLock l(thread->shared->GetMutex());
+          fprintf(
+              stdout,
+              "[CF %d] Dropping and recreating column family. new name: %s\n",
+              cf, new_name.c_str());
+        }
+        thread->shared->LockColumnFamily(cf);
+        Status s = db_->DropColumnFamily(column_families_[cf]);
+        delete column_families_[cf];
+        if (!s.ok()) {
+          fprintf(stderr, "dropping column family error: %s\n",
+              s.ToString().c_str());
+          std::terminate();
+        }
+        s = db_->CreateColumnFamily(ColumnFamilyOptions(options_), new_name,
+                                    &column_families_[cf]);
+        column_family_names_[cf] = new_name;
+        thread->shared->ClearColumnFamily(cf);
+        if (!s.ok()) {
+          fprintf(stderr, "creating column family error: %s\n",
+              s.ToString().c_str());
+          std::terminate();
+        }
+        thread->shared->UnlockColumnFamily(cf);
+      }
+    }
+  }
+
+  virtual bool ShouldAcquireMutexOnKey() const { return true; }
+
+  virtual Status TestGet(ThreadState* thread,
+      const ReadOptions& read_opts,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys) {
+    auto cfh = column_families_[rand_column_families[0]];
+    std::string key_str = Key(rand_keys[0]);
+    Slice key = key_str;
+    std::string from_db;
+    Status s = db_->Get(read_opts, cfh, key, &from_db);
+    if (s.ok()) {
+      // found case
+      thread->stats.AddGets(1, 1);
+    } else if (s.IsNotFound()) {
+      // not found case
+      thread->stats.AddGets(1, 0);
+    } else {
+      // errors case
+      thread->stats.AddErrors(1);
+    }
+    return s;
+  }
+
+  virtual Status TestPrefixScan(ThreadState* thread,
+      const ReadOptions& read_opts,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys) {
+    auto cfh = column_families_[rand_column_families[0]];
+    std::string key_str = Key(rand_keys[0]);
+    Slice key = key_str;
+    Slice prefix = Slice(key.data(), FLAGS_prefix_size);
+
+    std::string upper_bound;
+    Slice ub_slice;
+    ReadOptions ro_copy = read_opts;
+    if (thread->rand.OneIn(2) && GetNextPrefix(prefix, &upper_bound)) {
+      // For half of the time, set the upper bound to the next prefix
+      ub_slice = Slice(upper_bound);
+      ro_copy.iterate_upper_bound = &ub_slice;
+    }
+
+    Iterator* iter = db_->NewIterator(ro_copy, cfh);
+    long count = 0;
+    for (iter->Seek(prefix);
+        iter->Valid() && iter->key().starts_with(prefix); iter->Next()) {
+      ++count;
+    }
+    assert(count <= (static_cast<long>(1) << ((8 - FLAGS_prefix_size) * 8)));
+    Status s = iter->status();
+    if (iter->status().ok()) {
+      thread->stats.AddPrefixes(1, count);
+    } else {
+      thread->stats.AddErrors(1);
+    }
+    delete iter;
+    return s;
+  }
+
+  virtual Status TestPut(ThreadState* thread,
+      WriteOptions& write_opts, const ReadOptions& read_opts,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys,
+      char (&value) [100], std::unique_ptr<MutexLock>& lock) {
+    auto shared = thread->shared;
+    int64_t max_key = shared->GetMaxKey();
+    int64_t rand_key = rand_keys[0];
+    int rand_column_family = rand_column_families[0];
+    while (!shared->AllowsOverwrite(rand_key) &&
+           (FLAGS_use_merge || shared->Exists(rand_column_family, rand_key))) {
+      lock.reset();
+      rand_key = thread->rand.Next() % max_key;
+      rand_column_family = thread->rand.Next() % FLAGS_column_families;
+      lock.reset(new MutexLock(
+          shared->GetMutexForKey(rand_column_family, rand_key)));
+    }
+
+    std::string key_str = Key(rand_key);
+    Slice key = key_str;
+    ColumnFamilyHandle* cfh = column_families_[rand_column_family];
+
+    if (FLAGS_verify_before_write) {
+      std::string key_str2 = Key(rand_key);
+      Slice k = key_str2;
+      std::string from_db;
+      Status s = db_->Get(read_opts, cfh, k, &from_db);
+      if (!VerifyValue(rand_column_family, rand_key, read_opts, shared,
+            from_db, s, true)) {
+        return s;
+      }
+    }
+    uint32_t value_base = thread->rand.Next() % shared->UNKNOWN_SENTINEL;
+    size_t sz = GenerateValue(value_base, value, sizeof(value));
+    Slice v(value, sz);
+    shared->Put(rand_column_family, rand_key, value_base, true /* pending */);
+    Status s;
+    if (FLAGS_use_merge) {
+      if (!FLAGS_use_txn) {
+        s = db_->Merge(write_opts, cfh, key, v);
+      } else {
+#ifndef ROCKSDB_LITE
+        Transaction* txn;
+        s = NewTxn(write_opts, &txn);
+        if (s.ok()) {
+          s = txn->Merge(cfh, key, v);
+          if (s.ok()) {
+            s = CommitTxn(txn);
+          }
+        }
+#endif
+      }
+    } else {
+      if (!FLAGS_use_txn) {
+        s = db_->Put(write_opts, cfh, key, v);
+      } else {
+#ifndef ROCKSDB_LITE
+        Transaction* txn;
+        s = NewTxn(write_opts, &txn);
+        if (s.ok()) {
+          s = txn->Put(cfh, key, v);
+          if (s.ok()) {
+            s = CommitTxn(txn);
+          }
+        }
+#endif
+      }
+    }
+    shared->Put(rand_column_family, rand_key, value_base, false /* pending */);
+    if (!s.ok()) {
+      fprintf(stderr, "put or merge error: %s\n", s.ToString().c_str());
+      std::terminate();
+    }
+    thread->stats.AddBytesForWrites(1, sz);
+    PrintKeyValue(rand_column_family, static_cast<uint32_t>(rand_key),
+        value, sz);
+    return s;
+  }
+
+  virtual Status TestDelete(ThreadState* thread, WriteOptions& write_opts,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys,
+      std::unique_ptr<MutexLock>& lock) {
+    int64_t rand_key = rand_keys[0];
+    int rand_column_family = rand_column_families[0];
+    auto shared = thread->shared;
+    int64_t max_key = shared->GetMaxKey();
+
+    // OPERATION delete
+    // If the chosen key does not allow overwrite and it does not exist,
+    // choose another key.
+    while (!shared->AllowsOverwrite(rand_key) &&
+           !shared->Exists(rand_column_family, rand_key)) {
+      lock.reset();
+      rand_key = thread->rand.Next() % max_key;
+      rand_column_family = thread->rand.Next() % FLAGS_column_families;
+      lock.reset(new MutexLock(
+          shared->GetMutexForKey(rand_column_family, rand_key)));
+    }
+
+    std::string key_str = Key(rand_key);
+    Slice key = key_str;
+    auto cfh = column_families_[rand_column_family];
+
+    // Use delete if the key may be overwritten and a single deletion
+    // otherwise.
+    Status s;
+    if (shared->AllowsOverwrite(rand_key)) {
+      shared->Delete(rand_column_family, rand_key, true /* pending */);
+      if (!FLAGS_use_txn) {
+        s = db_->Delete(write_opts, cfh, key);
+      } else {
+#ifndef ROCKSDB_LITE
+        Transaction* txn;
+        s = NewTxn(write_opts, &txn);
+        if (s.ok()) {
+          s = txn->Delete(cfh, key);
+          if (s.ok()) {
+            s = CommitTxn(txn);
+          }
+        }
+#endif
+      }
+      shared->Delete(rand_column_family, rand_key, false /* pending */);
+      thread->stats.AddDeletes(1);
+      if (!s.ok()) {
+        fprintf(stderr, "delete error: %s\n", s.ToString().c_str());
+        std::terminate();
+      }
+    } else {
+      shared->SingleDelete(rand_column_family, rand_key, true /* pending */);
+      if (!FLAGS_use_txn) {
+        s = db_->SingleDelete(write_opts, cfh, key);
+      } else {
+#ifndef ROCKSDB_LITE
+        Transaction* txn;
+        s = NewTxn(write_opts, &txn);
+        if (s.ok()) {
+          s = txn->SingleDelete(cfh, key);
+          if (s.ok()) {
+            s = CommitTxn(txn);
+          }
+        }
+#endif
+      }
+      shared->SingleDelete(rand_column_family, rand_key, false /* pending */);
+      thread->stats.AddSingleDeletes(1);
+      if (!s.ok()) {
+        fprintf(stderr, "single delete error: %s\n",
+                s.ToString().c_str());
+        std::terminate();
+      }
+    }
+    return s;
+  }
+
+  virtual Status TestDeleteRange(ThreadState* thread,
+      WriteOptions& write_opts,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys,
+      std::unique_ptr<MutexLock>& lock) {
+    // OPERATION delete range
+    std::vector<std::unique_ptr<MutexLock>> range_locks;
+    // delete range does not respect disallowed overwrites. the keys for
+    // which overwrites are disallowed are randomly distributed so it
+    // could be expensive to find a range where each key allows
+    // overwrites.
+    int64_t rand_key = rand_keys[0];
+    int rand_column_family = rand_column_families[0];
+    auto shared = thread->shared;
+    int64_t max_key = shared->GetMaxKey();
+    if (rand_key > max_key - FLAGS_range_deletion_width) {
+      lock.reset();
+      rand_key = thread->rand.Next() %
+                 (max_key - FLAGS_range_deletion_width + 1);
+      range_locks.emplace_back(new MutexLock(
+          shared->GetMutexForKey(rand_column_family, rand_key)));
+    } else {
+      range_locks.emplace_back(std::move(lock));
+    }
+    for (int j = 1; j < FLAGS_range_deletion_width; ++j) {
+      if (((rand_key + j) & ((1 << FLAGS_log2_keys_per_lock) - 1)) == 0) {
+        range_locks.emplace_back(new MutexLock(
+              shared->GetMutexForKey(rand_column_family, rand_key + j)));
+      }
+    }
+    shared->DeleteRange(rand_column_family, rand_key,
+                        rand_key + FLAGS_range_deletion_width,
+                        true /* pending */);
+
+    std::string keystr = Key(rand_key);
+    Slice key = keystr;
+    auto cfh = column_families_[rand_column_family];
+    std::string end_keystr = Key(rand_key + FLAGS_range_deletion_width);
+    Slice end_key = end_keystr;
+    Status s = db_->DeleteRange(write_opts, cfh, key, end_key);
+    if (!s.ok()) {
+      fprintf(stderr, "delete range error: %s\n",
+              s.ToString().c_str());
+      std::terminate();
+    }
+    int covered = shared->DeleteRange(
+        rand_column_family, rand_key,
+        rand_key + FLAGS_range_deletion_width, false /* pending */);
+    thread->stats.AddRangeDeletions(1);
+    thread->stats.AddCoveredByRangeDeletions(covered);
+    return s;
+  }
+
+#ifdef ROCKSDB_LITE
+  virtual void TestIngestExternalFile(
+      ThreadState* /* thread */,
+      const std::vector<int>& /* rand_column_families */,
+      const std::vector<int64_t>& /* rand_keys */,
+      std::unique_ptr<MutexLock>& /* lock */) {
+    assert(false);
+    fprintf(stderr,
+            "RocksDB lite does not support "
+            "TestIngestExternalFile\n");
+    std::terminate();
+  }
+#else
+  virtual void TestIngestExternalFile(
+      ThreadState* thread, const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys, std::unique_ptr<MutexLock>& lock) {
+    const std::string sst_filename =
+        FLAGS_db + "/." + ToString(thread->tid) + ".sst";
+    Status s;
+    if (FLAGS_env->FileExists(sst_filename).ok()) {
+      // Maybe we terminated abnormally before, so cleanup to give this file
+      // ingestion a clean slate
+      s = FLAGS_env->DeleteFile(sst_filename);
+    }
+
+    SstFileWriter sst_file_writer(EnvOptions(), options_);
+    if (s.ok()) {
+      s = sst_file_writer.Open(sst_filename);
+    }
+    int64_t key_base = rand_keys[0];
+    int column_family = rand_column_families[0];
+    std::vector<std::unique_ptr<MutexLock> > range_locks;
+    std::vector<uint32_t> values;
+    SharedState* shared = thread->shared;
+
+    // Grab locks, set pending state on expected values, and add keys
+    for (int64_t key = key_base;
+         s.ok() && key < std::min(key_base + FLAGS_ingest_external_file_width,
+                                  shared->GetMaxKey());
+         ++key) {
+      if (key == key_base) {
+        range_locks.emplace_back(std::move(lock));
+      } else if ((key & ((1 << FLAGS_log2_keys_per_lock) - 1)) == 0) {
+        range_locks.emplace_back(
+            new MutexLock(shared->GetMutexForKey(column_family, key)));
+      }
+
+      uint32_t value_base = thread->rand.Next() % shared->UNKNOWN_SENTINEL;
+      values.push_back(value_base);
+      shared->Put(column_family, key, value_base, true /* pending */);
+
+      char value[100];
+      size_t value_len = GenerateValue(value_base, value, sizeof(value));
+      auto key_str = Key(key);
+      s = sst_file_writer.Put(Slice(key_str), Slice(value, value_len));
+    }
+
+    if (s.ok()) {
+      s = sst_file_writer.Finish();
+    }
+    if (s.ok()) {
+      s = db_->IngestExternalFile(column_families_[column_family],
+                                  {sst_filename}, IngestExternalFileOptions());
+    }
+    if (!s.ok()) {
+      fprintf(stderr, "file ingestion error: %s\n", s.ToString().c_str());
+      std::terminate();
+    }
+    int64_t key = key_base;
+    for (int32_t value : values) {
+      shared->Put(column_family, key, value, false /* pending */);
+      ++key;
+    }
+  }
+#endif  // ROCKSDB_LITE
+
+  bool VerifyValue(int cf, int64_t key, const ReadOptions& /*opts*/,
+                   SharedState* shared, const std::string& value_from_db,
+                   Status s, bool strict = false) const {
+    if (shared->HasVerificationFailedYet()) {
+      return false;
+    }
+    // compare value_from_db with the value in the shared state
+    char value[kValueMaxLen];
+    uint32_t value_base = shared->Get(cf, key);
+    if (value_base == SharedState::UNKNOWN_SENTINEL) {
+      return true;
+    }
+    if (value_base == SharedState::DELETION_SENTINEL && !strict) {
+      return true;
+    }
+
+    if (s.ok()) {
+      if (value_base == SharedState::DELETION_SENTINEL) {
+        VerificationAbort(shared, "Unexpected value found", cf, key);
+        return false;
+      }
+      size_t sz = GenerateValue(value_base, value, sizeof(value));
+      if (value_from_db.length() != sz) {
+        VerificationAbort(shared, "Length of value read is not equal", cf, key);
+        return false;
+      }
+      if (memcmp(value_from_db.data(), value, sz) != 0) {
+        VerificationAbort(shared, "Contents of value read don't match", cf,
+                          key);
+        return false;
+      }
+    } else {
+      if (value_base != SharedState::DELETION_SENTINEL) {
+        VerificationAbort(shared, "Value not found: " + s.ToString(), cf, key);
+        return false;
+      }
+    }
+    return true;
+  }
+};
+
+class BatchedOpsStressTest : public StressTest {
+ public:
+  BatchedOpsStressTest() {}
+  virtual ~BatchedOpsStressTest() {}
+
+  // Given a key K and value V, this puts ("0"+K, "0"+V), ("1"+K, "1"+V), ...
+  // ("9"+K, "9"+V) in DB atomically i.e in a single batch.
+  // Also refer BatchedOpsStressTest::TestGet
+  virtual Status TestPut(ThreadState* thread,
+      WriteOptions& write_opts, const ReadOptions& /* read_opts */,
+      const std::vector<int>& rand_column_families, const std::vector<int64_t>& rand_keys,
+      char (&value)[100], std::unique_ptr<MutexLock>& /* lock */) {
+    uint32_t value_base =
+        thread->rand.Next() % thread->shared->UNKNOWN_SENTINEL;
+    size_t sz = GenerateValue(value_base, value, sizeof(value));
+    Slice v(value, sz);
+    std::string keys[10] = {"9", "8", "7", "6", "5",
+                            "4", "3", "2", "1", "0"};
+    std::string values[10] = {"9", "8", "7", "6", "5",
+                              "4", "3", "2", "1", "0"};
+    Slice value_slices[10];
+    WriteBatch batch;
+    Status s;
+    auto cfh = column_families_[rand_column_families[0]];
+    std::string key_str = Key(rand_keys[0]);
+    for (int i = 0; i < 10; i++) {
+      keys[i] += key_str;
+      values[i] += v.ToString();
+      value_slices[i] = values[i];
+      if (FLAGS_use_merge) {
+        batch.Merge(cfh, keys[i], value_slices[i]);
+      } else {
+        batch.Put(cfh, keys[i], value_slices[i]);
+      }
+    }
+
+    s = db_->Write(write_opts, &batch);
+    if (!s.ok()) {
+      fprintf(stderr, "multiput error: %s\n", s.ToString().c_str());
+      thread->stats.AddErrors(1);
+    } else {
+      // we did 10 writes each of size sz + 1
+      thread->stats.AddBytesForWrites(10, (sz + 1) * 10);
+    }
+
+    return s;
+  }
+
+  // Given a key K, this deletes ("0"+K), ("1"+K),... ("9"+K)
+  // in DB atomically i.e in a single batch. Also refer MultiGet.
+  virtual Status TestDelete(ThreadState* thread, WriteOptions& writeoptions,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys,
+      std::unique_ptr<MutexLock>& /* lock */) {
+    std::string keys[10] = {"9", "7", "5", "3", "1",
+                            "8", "6", "4", "2", "0"};
+
+    WriteBatch batch;
+    Status s;
+    auto cfh = column_families_[rand_column_families[0]];
+    std::string key_str = Key(rand_keys[0]);
+    for (int i = 0; i < 10; i++) {
+      keys[i] += key_str;
+      batch.Delete(cfh, keys[i]);
+    }
+
+    s = db_->Write(writeoptions, &batch);
+    if (!s.ok()) {
+      fprintf(stderr, "multidelete error: %s\n", s.ToString().c_str());
+      thread->stats.AddErrors(1);
+    } else {
+      thread->stats.AddDeletes(10);
+    }
+
+    return s;
+  }
+
+  virtual Status TestDeleteRange(ThreadState* /* thread */,
+      WriteOptions& /* write_opts */,
+      const std::vector<int>& /* rand_column_families */,
+      const std::vector<int64_t>& /* rand_keys */,
+      std::unique_ptr<MutexLock>& /* lock */) {
+    assert(false);
+    return Status::NotSupported("BatchedOpsStressTest does not support "
+        "TestDeleteRange");
+  }
+
+  virtual void TestIngestExternalFile(
+      ThreadState* /* thread */,
+      const std::vector<int>& /* rand_column_families */,
+      const std::vector<int64_t>& /* rand_keys */,
+      std::unique_ptr<MutexLock>& /* lock */) {
+    assert(false);
+    fprintf(stderr,
+            "BatchedOpsStressTest does not support "
+            "TestIngestExternalFile\n");
+    std::terminate();
+  }
+
+  // Given a key K, this gets values for "0"+K, "1"+K,..."9"+K
+  // in the same snapshot, and verifies that all the values are of the form
+  // "0"+V, "1"+V,..."9"+V.
+  // ASSUMES that BatchedOpsStressTest::TestPut was used to put (K, V) into
+  // the DB.
+  virtual Status TestGet(ThreadState* thread, const ReadOptions& readoptions,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys) {
+    std::string keys[10] = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};
+    Slice key_slices[10];
+    std::string values[10];
+    ReadOptions readoptionscopy = readoptions;
+    readoptionscopy.snapshot = db_->GetSnapshot();
+    std::string key_str = Key(rand_keys[0]);
+    Slice key = key_str;
+    auto cfh = column_families_[rand_column_families[0]];
+    std::string from_db;
+    Status s;
+    for (int i = 0; i < 10; i++) {
+      keys[i] += key.ToString();
+      key_slices[i] = keys[i];
+      s = db_->Get(readoptionscopy, cfh, key_slices[i], &from_db);
+      if (!s.ok() && !s.IsNotFound()) {
+        fprintf(stderr, "get error: %s\n", s.ToString().c_str());
+        values[i] = "";
+        thread->stats.AddErrors(1);
+        // we continue after error rather than exiting so that we can
+        // find more errors if any
+      } else if (s.IsNotFound()) {
+        values[i] = "";
+        thread->stats.AddGets(1, 0);
+      } else {
+        values[i] = from_db;
+
+        char expected_prefix = (keys[i])[0];
+        char actual_prefix = (values[i])[0];
+        if (actual_prefix != expected_prefix) {
+          fprintf(stderr, "error expected prefix = %c actual = %c\n",
+                  expected_prefix, actual_prefix);
+        }
+        (values[i])[0] = ' '; // blank out the differing character
+        thread->stats.AddGets(1, 1);
+      }
+    }
+    db_->ReleaseSnapshot(readoptionscopy.snapshot);
+
+    // Now that we retrieved all values, check that they all match
+    for (int i = 1; i < 10; i++) {
+      if (values[i] != values[0]) {
+        fprintf(stderr, "error : inconsistent values for key %s: %s, %s\n",
+                key.ToString(true).c_str(), StringToHex(values[0]).c_str(),
+                StringToHex(values[i]).c_str());
+      // we continue after error rather than exiting so that we can
+      // find more errors if any
+      }
+    }
+
+    return s;
+  }
+
+  // Given a key, this does prefix scans for "0"+P, "1"+P,..."9"+P
+  // in the same snapshot where P is the first FLAGS_prefix_size - 1 bytes
+  // of the key. Each of these 10 scans returns a series of values;
+  // each series should be the same length, and it is verified for each
+  // index i that all the i'th values are of the form "0"+V, "1"+V,..."9"+V.
+  // ASSUMES that MultiPut was used to put (K, V)
+  virtual Status TestPrefixScan(ThreadState* thread, const ReadOptions& readoptions,
+      const std::vector<int>& rand_column_families,
+      const std::vector<int64_t>& rand_keys) {
+    std::string key_str = Key(rand_keys[0]);
+    Slice key = key_str;
+    auto cfh = column_families_[rand_column_families[0]];
+    std::string prefixes[10] = {"0", "1", "2", "3", "4",
+                                "5", "6", "7", "8", "9"};
+    Slice prefix_slices[10];
+    ReadOptions readoptionscopy[10];
+    const Snapshot* snapshot = db_->GetSnapshot();
+    Iterator* iters[10];
+    std::string upper_bounds[10];
+    Slice ub_slices[10];
+    Status s = Status::OK();
+    for (int i = 0; i < 10; i++) {
+      prefixes[i] += key.ToString();
+      prefixes[i].resize(FLAGS_prefix_size);
+      prefix_slices[i] = Slice(prefixes[i]);
+      readoptionscopy[i] = readoptions;
+      readoptionscopy[i].snapshot = snapshot;
+      if (thread->rand.OneIn(2) &&
+          GetNextPrefix(prefix_slices[i], &(upper_bounds[i]))) {
+        // For half of the time, set the upper bound to the next prefix
+        ub_slices[i] = Slice(upper_bounds[i]);
+        readoptionscopy[i].iterate_upper_bound = &(ub_slices[i]);
+      }
+      iters[i] = db_->NewIterator(readoptionscopy[i], cfh);
+      iters[i]->Seek(prefix_slices[i]);
+    }
+
+    long count = 0;
+    while (iters[0]->Valid() && iters[0]->key().starts_with(prefix_slices[0])) {
+      count++;
+      std::string values[10];
+      // get list of all values for this iteration
+      for (int i = 0; i < 10; i++) {
+        // no iterator should finish before the first one
+        assert(iters[i]->Valid() &&
+               iters[i]->key().starts_with(prefix_slices[i]));
+        values[i] = iters[i]->value().ToString();
+
+        char expected_first = (prefixes[i])[0];
+        char actual_first = (values[i])[0];
+
+        if (actual_first != expected_first) {
+          fprintf(stderr, "error expected first = %c actual = %c\n",
+                  expected_first, actual_first);
+        }
+        (values[i])[0] = ' '; // blank out the differing character
+      }
+      // make sure all values are equivalent
+      for (int i = 0; i < 10; i++) {
+        if (values[i] != values[0]) {
+          fprintf(stderr, "error : %d, inconsistent values for prefix %s: %s, %s\n",
+                  i, prefixes[i].c_str(), StringToHex(values[0]).c_str(),
+                  StringToHex(values[i]).c_str());
+          // we continue after error rather than exiting so that we can
+          // find more errors if any
+        }
+        iters[i]->Next();
+      }
+    }
+
+    // cleanup iterators and snapshot
+    for (int i = 0; i < 10; i++) {
+      // if the first iterator finished, they should have all finished
+      assert(!iters[i]->Valid() ||
+             !iters[i]->key().starts_with(prefix_slices[i]));
+      assert(iters[i]->status().ok());
+      delete iters[i];
+    }
+    db_->ReleaseSnapshot(snapshot);
+
+    if (s.ok()) {
+      thread->stats.AddPrefixes(1, count);
+    } else {
+      thread->stats.AddErrors(1);
+    }
+
+    return s;
+  }
+
+  virtual void VerifyDb(ThreadState* /* thread */) const {}
+};
+
+class AtomicFlushStressTest : public StressTest {
+ public:
+  AtomicFlushStressTest() : batch_id_(0) {}
+
+  virtual ~AtomicFlushStressTest() {}
+
+  virtual Status TestPut(ThreadState* thread, WriteOptions& write_opts,
+                         const ReadOptions& /* read_opts */,
+                         const std::vector<int>& rand_column_families,
+                         const std::vector<int64_t>& rand_keys,
+                         char (&value)[100],
+                         std::unique_ptr<MutexLock>& /* lock */) {
+    std::string key_str = Key(rand_keys[0]);
+    Slice key = key_str;
+    uint64_t value_base = batch_id_.fetch_add(1);
+    size_t sz =
+        GenerateValue(static_cast<uint32_t>(value_base), value, sizeof(value));
+    Slice v(value, sz);
+    WriteBatch batch;
+    for (auto cf : rand_column_families) {
+      ColumnFamilyHandle* cfh = column_families_[cf];
+      if (FLAGS_use_merge) {
+        batch.Merge(cfh, key, v);
+      } else { /* !FLAGS_use_merge */
+        batch.Put(cfh, key, v);
+      }
+    }
+    Status s = db_->Write(write_opts, &batch);
+    if (!s.ok()) {
+      fprintf(stderr, "multi put or merge error: %s\n", s.ToString().c_str());
+      thread->stats.AddErrors(1);
+    } else {
+      auto num = static_cast<long>(rand_column_families.size());
+      thread->stats.AddBytesForWrites(num, (sz + 1) * num);
+    }
+
+    return s;
+  }
+
+  virtual Status TestDelete(ThreadState* thread, WriteOptions& write_opts,
+                            const std::vector<int>& rand_column_families,
+                            const std::vector<int64_t>& rand_keys,
+                            std::unique_ptr<MutexLock>& /* lock */) {
+    std::string key_str = Key(rand_keys[0]);
+    Slice key = key_str;
+    WriteBatch batch;
+    for (auto cf : rand_column_families) {
+      ColumnFamilyHandle* cfh = column_families_[cf];
+      batch.Delete(cfh, key);
+    }
+    Status s = db_->Write(write_opts, &batch);
+    if (!s.ok()) {
+      fprintf(stderr, "multidel error: %s\n", s.ToString().c_str());
+      thread->stats.AddErrors(1);
+    } else {
+      thread->stats.AddDeletes(static_cast<long>(rand_column_families.size()));
+    }
+    return s;
+  }
+
+  virtual Status TestDeleteRange(ThreadState* thread, WriteOptions& write_opts,
+                                 const std::vector<int>& rand_column_families,
+                                 const std::vector<int64_t>& rand_keys,
+                                 std::unique_ptr<MutexLock>& /* lock */) {
+    int64_t rand_key = rand_keys[0];
+    auto shared = thread->shared;
+    int64_t max_key = shared->GetMaxKey();
+    if (rand_key > max_key - FLAGS_range_deletion_width) {
+      rand_key =
+          thread->rand.Next() % (max_key - FLAGS_range_deletion_width + 1);
+    }
+    std::string key_str = Key(rand_key);
+    Slice key = key_str;
+    std::string end_key_str = Key(rand_key + FLAGS_range_deletion_width);
+    Slice end_key = end_key_str;
+    WriteBatch batch;
+    for (auto cf : rand_column_families) {
+      ColumnFamilyHandle* cfh = column_families_[rand_column_families[cf]];
+      batch.DeleteRange(cfh, key, end_key);
+    }
+    Status s = db_->Write(write_opts, &batch);
+    if (!s.ok()) {
+      fprintf(stderr, "multi del range error: %s\n", s.ToString().c_str());
+      thread->stats.AddErrors(1);
+    } else {
+      thread->stats.AddRangeDeletions(
+          static_cast<long>(rand_column_families.size()));
+    }
+    return s;
+  }
+
+  virtual void TestIngestExternalFile(
+      ThreadState* /* thread */,
+      const std::vector<int>& /* rand_column_families */,
+      const std::vector<int64_t>& /* rand_keys */,
+      std::unique_ptr<MutexLock>& /* lock */) {
+    assert(false);
+    fprintf(stderr,
+            "AtomicFlushStressTest does not support TestIngestExternalFile "
+            "because it's not possible to verify the result\n");
+    std::terminate();
+  }
+
+  virtual Status TestGet(ThreadState* thread, const ReadOptions& readoptions,
+                         const std::vector<int>& rand_column_families,
+                         const std::vector<int64_t>& rand_keys) {
+    std::string key_str = Key(rand_keys[0]);
+    Slice key = key_str;
+    auto cfh =
+        column_families_[rand_column_families[thread->rand.Next() %
+                                              rand_column_families.size()]];
+    std::string from_db;
+    Status s = db_->Get(readoptions, cfh, key, &from_db);
+    if (s.ok()) {
+      thread->stats.AddGets(1, 1);
+    } else if (s.IsNotFound()) {
+      thread->stats.AddGets(1, 0);
+    } else {
+      thread->stats.AddErrors(1);
+    }
+    return s;
+  }
+
+  virtual Status TestPrefixScan(ThreadState* thread,
+                                const ReadOptions& readoptions,
+                                const std::vector<int>& rand_column_families,
+                                const std::vector<int64_t>& rand_keys) {
+    std::string key_str = Key(rand_keys[0]);
+    Slice key = key_str;
+    Slice prefix = Slice(key.data(), FLAGS_prefix_size);
+
+    std::string upper_bound;
+    Slice ub_slice;
+    ReadOptions ro_copy = readoptions;
+    if (thread->rand.OneIn(2) && GetNextPrefix(prefix, &upper_bound)) {
+      ub_slice = Slice(upper_bound);
+      ro_copy.iterate_upper_bound = &ub_slice;
+    }
+    auto cfh =
+        column_families_[rand_column_families[thread->rand.Next() %
+                                              rand_column_families.size()]];
+    Iterator* iter = db_->NewIterator(ro_copy, cfh);
+    long count = 0;
+    for (iter->Seek(prefix); iter->Valid() && iter->key().starts_with(prefix);
+         iter->Next()) {
+      ++count;
+    }
+    assert(count <= (static_cast<long>(1) << ((8 - FLAGS_prefix_size) * 8)));
+    Status s = iter->status();
+    if (s.ok()) {
+      thread->stats.AddPrefixes(1, count);
+    } else {
+      thread->stats.AddErrors(1);
+    }
+    delete iter;
+    return s;
+  }
+
+#ifdef ROCKSDB_LITE
+  virtual Status TestCheckpoint(
+      ThreadState* /* thread */,
+      const std::vector<int>& /* rand_column_families */,
+      const std::vector<int64_t>& /* rand_keys */) {
+    assert(false);
+    fprintf(stderr,
+            "RocksDB lite does not support "
+            "TestCheckpoint\n");
+    std::terminate();
+  }
+#else
+  virtual Status TestCheckpoint(
+      ThreadState* thread, const std::vector<int>& /* rand_column_families */,
+      const std::vector<int64_t>& /* rand_keys */) {
+    std::string checkpoint_dir =
+        FLAGS_db + "/.checkpoint" + ToString(thread->tid);
+    DestroyDB(checkpoint_dir, Options());
+    Checkpoint* checkpoint = nullptr;
+    Status s = Checkpoint::Create(db_, &checkpoint);
+    if (s.ok()) {
+      s = checkpoint->CreateCheckpoint(checkpoint_dir);
+    }
+    std::vector<ColumnFamilyHandle*> cf_handles;
+    DB* checkpoint_db = nullptr;
+    if (s.ok()) {
+      delete checkpoint;
+      checkpoint = nullptr;
+      Options options(options_);
+      options.listeners.clear();
+      std::vector<ColumnFamilyDescriptor> cf_descs;
+      // TODO(ajkr): `column_family_names_` is not safe to access here when
+      // `clear_column_family_one_in != 0`. But we can't easily switch to
+      // `ListColumnFamilies` to get names because it won't necessarily give
+      // the same order as `column_family_names_`.
+      if (FLAGS_clear_column_family_one_in == 0) {
+        for (const auto& name : column_family_names_) {
+          cf_descs.emplace_back(name, ColumnFamilyOptions(options));
+        }
+        s = DB::OpenForReadOnly(DBOptions(options), checkpoint_dir, cf_descs,
+                                &cf_handles, &checkpoint_db);
+      }
+    }
+    if (checkpoint_db != nullptr) {
+      for (auto cfh : cf_handles) {
+        delete cfh;
+      }
+      cf_handles.clear();
+      delete checkpoint_db;
+      checkpoint_db = nullptr;
+    }
+    DestroyDB(checkpoint_dir, Options());
+    if (!s.ok()) {
+      fprintf(stderr, "A checkpoint operation failed with: %s\n",
+              s.ToString().c_str());
+    }
+    return s;
+  }
+#endif  // !ROCKSDB_LITE
+
+  virtual void VerifyDb(ThreadState* thread) const {
+    ReadOptions options(FLAGS_verify_checksum, true);
+    // We must set total_order_seek to true because we are doing a SeekToFirst
+    // on a column family whose memtables may support (by default) prefix-based
+    // iterator. In this case, NewIterator with options.total_order_seek being
+    // false returns a prefix-based iterator. Calling SeekToFirst using this
+    // iterator causes the iterator to become invalid. That means we cannot
+    // iterate the memtable using this iterator any more, although the memtable
+    // contains the most up-to-date key-values.
+    options.total_order_seek = true;
+    assert(thread != nullptr);
+    auto shared = thread->shared;
+    std::vector<std::unique_ptr<Iterator> > iters(column_families_.size());
+    for (size_t i = 0; i != column_families_.size(); ++i) {
+      iters[i].reset(db_->NewIterator(options, column_families_[i]));
+    }
+    for (auto& iter : iters) {
+      iter->SeekToFirst();
+    }
+    size_t num = column_families_.size();
+    assert(num == iters.size());
+    std::vector<Status> statuses(num, Status::OK());
+    do {
+      size_t valid_cnt = 0;
+      size_t idx = 0;
+      for (auto& iter : iters) {
+        if (iter->Valid()) {
+          ++valid_cnt;
+        } else {
+          statuses[idx] = iter->status();
+        }
+        ++idx;
+      }
+      if (valid_cnt == 0) {
+        Status status;
+        for (size_t i = 0; i != num; ++i) {
+          const auto& s = statuses[i];
+          if (!s.ok()) {
+            status = s;
+            fprintf(stderr, "Iterator on cf %s has error: %s\n",
+                    column_families_[i]->GetName().c_str(),
+                    s.ToString().c_str());
+            shared->SetVerificationFailure();
+          }
+        }
+        if (status.ok()) {
+          fprintf(stdout, "Finished scanning all column families.\n");
+        }
+        break;
+      } else if (valid_cnt != iters.size()) {
+        for (size_t i = 0; i != num; ++i) {
+          if (!iters[i]->Valid()) {
+            if (statuses[i].ok()) {
+              fprintf(stderr, "Finished scanning cf %s\n",
+                      column_families_[i]->GetName().c_str());
+            } else {
+              fprintf(stderr, "Iterator on cf %s has error: %s\n",
+                      column_families_[i]->GetName().c_str(),
+                      statuses[i].ToString().c_str());
+            }
+          } else {
+            fprintf(stderr, "cf %s has remaining data to scan\n",
+                    column_families_[i]->GetName().c_str());
+          }
+        }
+        shared->SetVerificationFailure();
+        break;
+      }
+      // If the program reaches here, then all column families' iterators are
+      // still valid.
+      Slice key;
+      Slice value;
+      for (size_t i = 0; i != num; ++i) {
+        if (i == 0) {
+          key = iters[i]->key();
+          value = iters[i]->value();
+        } else {
+          if (key.compare(iters[i]->key()) != 0) {
+            fprintf(stderr, "Verification failed\n");
+            fprintf(stderr, "cf%s: %s => %s\n",
+                    column_families_[0]->GetName().c_str(),
+                    key.ToString(true /* hex */).c_str(),
+                    value.ToString(/* hex */).c_str());
+            fprintf(stderr, "cf%s: %s => %s\n",
+                    column_families_[i]->GetName().c_str(),
+                    iters[i]->key().ToString(true /* hex */).c_str(),
+                    iters[i]->value().ToString(true /* hex */).c_str());
+            shared->SetVerificationFailure();
+          }
+        }
+      }
+      for (auto& iter : iters) {
+        iter->Next();
+      }
+    } while (true);
+  }
+
+  virtual std::vector<int> GenerateColumnFamilies(
+      const int /* num_column_families */, int /* rand_column_family */) const {
+    std::vector<int> ret;
+    int num = static_cast<int>(column_families_.size());
+    int k = 0;
+    std::generate_n(back_inserter(ret), num, [&k]() -> int { return k++; });
+    return ret;
+  }
+
+ private:
+  std::atomic<int64_t> batch_id_;
+};
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) +
+                  " [OPTIONS]...");
+  ParseCommandLineFlags(&argc, &argv, true);
+
+  if (FLAGS_statistics) {
+    dbstats = rocksdb::CreateDBStatistics();
+  }
+  FLAGS_compression_type_e =
+    StringToCompressionType(FLAGS_compression_type.c_str());
+  FLAGS_checksum_type_e = StringToChecksumType(FLAGS_checksum_type.c_str());
+  if (!FLAGS_hdfs.empty()) {
+    FLAGS_env  = new rocksdb::HdfsEnv(FLAGS_hdfs);
+  }
+  FLAGS_rep_factory = StringToRepFactory(FLAGS_memtablerep.c_str());
+
+  // The number of background threads should be at least as much the
+  // max number of concurrent compactions.
+  FLAGS_env->SetBackgroundThreads(FLAGS_max_background_compactions);
+  FLAGS_env->SetBackgroundThreads(FLAGS_num_bottom_pri_threads,
+                                  rocksdb::Env::Priority::BOTTOM);
+  if (FLAGS_prefixpercent > 0 && FLAGS_prefix_size <= 0) {
+    fprintf(stderr,
+            "Error: prefixpercent is non-zero while prefix_size is "
+            "not positive!\n");
+    exit(1);
+  }
+  if (FLAGS_test_batches_snapshots && FLAGS_prefix_size <= 0) {
+    fprintf(stderr,
+            "Error: please specify prefix_size for "
+            "test_batches_snapshots test!\n");
+    exit(1);
+  }
+  if (FLAGS_memtable_prefix_bloom_size_ratio > 0.0 && FLAGS_prefix_size <= 0) {
+    fprintf(stderr,
+            "Error: please specify positive prefix_size in order to use "
+            "memtable_prefix_bloom_size_ratio\n");
+    exit(1);
+  }
+  if ((FLAGS_readpercent + FLAGS_prefixpercent +
+       FLAGS_writepercent + FLAGS_delpercent + FLAGS_delrangepercent +
+       FLAGS_iterpercent) != 100) {
+      fprintf(stderr,
+              "Error: Read+Prefix+Write+Delete+DeleteRange+Iterate percents != "
+              "100!\n");
+      exit(1);
+  }
+  if (FLAGS_disable_wal == 1 && FLAGS_reopen > 0) {
+    fprintf(stderr, "Error: Db cannot reopen safely with disable_wal set!\n");
+    exit(1);
+  }
+  if ((unsigned)FLAGS_reopen >= FLAGS_ops_per_thread) {
+      fprintf(stderr,
+              "Error: #DB-reopens should be < ops_per_thread\n"
+              "Provided reopens = %d and ops_per_thread = %lu\n",
+              FLAGS_reopen,
+              (unsigned long)FLAGS_ops_per_thread);
+      exit(1);
+  }
+  if (FLAGS_test_batches_snapshots && FLAGS_delrangepercent > 0) {
+    fprintf(stderr, "Error: nonzero delrangepercent unsupported in "
+                    "test_batches_snapshots mode\n");
+    exit(1);
+  }
+  if (FLAGS_active_width > FLAGS_max_key) {
+    fprintf(stderr, "Error: active_width can be at most max_key\n");
+    exit(1);
+  } else if (FLAGS_active_width == 0) {
+    FLAGS_active_width = FLAGS_max_key;
+  }
+  if (FLAGS_value_size_mult * kRandomValueMaxFactor > kValueMaxLen) {
+    fprintf(stderr, "Error: value_size_mult can be at most %d\n",
+            kValueMaxLen / kRandomValueMaxFactor);
+    exit(1);
+  }
+  if (FLAGS_use_merge && FLAGS_nooverwritepercent == 100) {
+    fprintf(
+        stderr,
+        "Error: nooverwritepercent must not be 100 when using merge operands");
+    exit(1);
+  }
+  if (FLAGS_ingest_external_file_one_in > 0 && FLAGS_nooverwritepercent > 0) {
+    fprintf(stderr,
+            "Error: nooverwritepercent must be 0 when using file ingestion\n");
+    exit(1);
+  }
+  if (FLAGS_clear_column_family_one_in > 0 && FLAGS_backup_one_in > 0) {
+    fprintf(stderr,
+            "Error: clear_column_family_one_in must be 0 when using backup\n");
+    exit(1);
+  }
+  if (FLAGS_test_atomic_flush) {
+    FLAGS_atomic_flush = true;
+  }
+  if (FLAGS_read_only) {
+    if (FLAGS_writepercent != 0 || FLAGS_delpercent != 0 ||
+        FLAGS_delrangepercent != 0) {
+      fprintf(stderr, "Error: updates are not supported in read only mode\n");
+      exit(1);
+    } else if (FLAGS_checkpoint_one_in > 0 &&
+               FLAGS_clear_column_family_one_in > 0) {
+      fprintf(stdout,
+              "Warn: checkpoint won't be validated since column families may "
+              "be dropped.\n");
+    }
+  }
+
+  // Choose a location for the test database if none given with --db=<path>
+  if (FLAGS_db.empty()) {
+      std::string default_db_path;
+      rocksdb::Env::Default()->GetTestDirectory(&default_db_path);
+      default_db_path += "/dbstress";
+      FLAGS_db = default_db_path;
+  }
+
+  rocksdb_kill_odds = FLAGS_kill_random_test;
+  rocksdb_kill_prefix_blacklist = SplitString(FLAGS_kill_prefix_blacklist);
+
+  std::unique_ptr<rocksdb::StressTest> stress;
+  if (FLAGS_test_atomic_flush) {
+    stress.reset(new rocksdb::AtomicFlushStressTest());
+  } else if (FLAGS_test_batches_snapshots) {
+    stress.reset(new rocksdb::BatchedOpsStressTest());
+  } else {
+    stress.reset(new rocksdb::NonBatchedOpsStressTest());
+  }
+  if (stress->Run()) {
+    return 0;
+  } else {
+    return 1;
+  }
+}
+
+#endif  // GFLAGS
diff --git a/src/rocksdb/tools/dbench_monitor b/src/rocksdb/tools/dbench_monitor
new file mode 100755
index 00000000..d85f9d07
--- /dev/null
+++ b/src/rocksdb/tools/dbench_monitor
@@ -0,0 +1,102 @@
+#!/usr/bin/env bash
+#
+#(c) 2004-present, Facebook Inc. All rights reserved.
+#
+#see LICENSE file for more information on use/redistribution rights.
+#
+
+#
+#dbench_monitor: monitor db_bench process for violation of memory utilization
+#
+#default usage will monitor 'virtual memory size'. See below for standard options
+#passed to db_bench during this test.
+#
+# See also: ./pflag for the actual monitoring script that does the work
+#
+#NOTE:
+#  You may end up with some /tmp/ files if db_bench OR
+#  this script OR ./pflag was killed unceremoniously
+#
+#  If you see the script taking a long time, trying "kill"
+#  will usually cleanly exit.
+#
+#
+DIR=`dirname $0`
+LOG=/tmp/`basename $0`.$$
+DB_BENCH="$DIR/../db_bench";
+PFLAG=${DIR}/pflag
+
+usage() {
+    cat <<HELP; exit
+
+Usage: $0  [-h]
+
+-h: prints this help message
+
+This program will run the db_bench script to monitor memory usage
+using the 'pflag' program. It launches db_bench with default settings
+for certain arguments. You can change the defaults passed to
+'db_bench' program, by setting the following environment 
+variables:
+
+  bs [block_size]
+  ztype [compression_type]
+  benches [benchmarks]
+  reads [reads]
+  threads [threads]
+  cs [cache_size]
+  vsize [value_size]
+  comp [compression_ratio]
+  num [num]
+
+See the code for more info
+
+HELP
+
+}
+
+[ ! -x ${DB_BENCH} ] && echo "WARNING: ${DB_BENCH} doesn't exist, abort!" && exit -1;
+
+[ "x$1" = "x-h" ] && usage;
+
+trap 'rm -f ${LOG}; kill ${PID}; echo "Interrupted, exiting";' 1 2 3 15
+
+touch $LOG;
+
+: ${bs:=16384}
+: ${ztype:=zlib}
+: ${benches:=readwhilewriting}
+: ${reads:=$((1*1024*1024))};
+: ${threads:=8}
+: ${vsize:=2000}
+: ${comp:=0.5}
+: ${num:=10000}
+: ${cs:=$((1*1024*1024*1024))};
+
+DEBUG=1    #Set to 0 to remove chattiness 
+
+
+if [ "x$DEBUG" != "x" ]; then
+  #
+  #NOTE: under some circumstances, --use_existing_db may leave LOCK files under ${TMPDIR}/rocksdb/*
+  #cleanup the dir and re-run
+  #
+  echo DEBUG: Will run $DB_BENCH --block_size=$bs --compression_type=$ztype --benchmarks="$benches" --reads="$reads" --threads="$threads" --cache_size=$cs  --value_size=$vsize --compression_ratio=$comp --num=$num --use_existing_db 
+
+fi
+
+$DB_BENCH --block_size=$bs --compression_type=$ztype --benchmarks="$benches" --reads="$reads" --threads="$threads" --cache_size=$cs  --value_size=$vsize --compression_ratio=$comp --num=$num --use_existing_db >$LOG 2>&1 &
+
+if [ $? -ne 0 ]; then
+  warn "WARNING: ${DB_BENCH} did not launch successfully! Abort!";
+  exit;
+fi
+PID=$!
+
+#
+#Start the monitoring. Default is "vsz" monitoring for upto cache_size ($cs) value of virtual mem
+#You could also monitor RSS and CPUTIME (bsdtime). Try 'pflag -h' for how to do this
+#
+${PFLAG} -p $PID -v
+
+rm -f $LOG;
diff --git a/src/rocksdb/tools/dump/db_dump_tool.cc b/src/rocksdb/tools/dump/db_dump_tool.cc
new file mode 100644
index 00000000..8c5fa82e
--- /dev/null
+++ b/src/rocksdb/tools/dump/db_dump_tool.cc
@@ -0,0 +1,261 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#ifndef ROCKSDB_LITE
+
+#ifndef __STDC_FORMAT_MACROS
+#define __STDC_FORMAT_MACROS
+#endif
+
+#include <inttypes.h>
+#include <iostream>
+
+#include "rocksdb/db.h"
+#include "rocksdb/db_dump_tool.h"
+#include "rocksdb/env.h"
+#include "util/coding.h"
+
+namespace rocksdb {
+
+bool DbDumpTool::Run(const DumpOptions& dump_options,
+                     rocksdb::Options options) {
+  rocksdb::DB* dbptr;
+  rocksdb::Status status;
+  std::unique_ptr<rocksdb::WritableFile> dumpfile;
+  char hostname[1024];
+  int64_t timesec = 0;
+  std::string abspath;
+  char json[4096];
+
+  static const char* magicstr = "ROCKDUMP";
+  static const char versionstr[8] = {0, 0, 0, 0, 0, 0, 0, 1};
+
+  rocksdb::Env* env = rocksdb::Env::Default();
+
+  // Open the database
+  options.create_if_missing = false;
+  status = rocksdb::DB::OpenForReadOnly(options, dump_options.db_path, &dbptr);
+  if (!status.ok()) {
+    std::cerr << "Unable to open database '" << dump_options.db_path
+              << "' for reading: " << status.ToString() << std::endl;
+    return false;
+  }
+
+  const std::unique_ptr<rocksdb::DB> db(dbptr);
+
+  status = env->NewWritableFile(dump_options.dump_location, &dumpfile,
+                                rocksdb::EnvOptions());
+  if (!status.ok()) {
+    std::cerr << "Unable to open dump file '" << dump_options.dump_location
+              << "' for writing: " << status.ToString() << std::endl;
+    return false;
+  }
+
+  rocksdb::Slice magicslice(magicstr, 8);
+  status = dumpfile->Append(magicslice);
+  if (!status.ok()) {
+    std::cerr << "Append failed: " << status.ToString() << std::endl;
+    return false;
+  }
+
+  rocksdb::Slice versionslice(versionstr, 8);
+  status = dumpfile->Append(versionslice);
+  if (!status.ok()) {
+    std::cerr << "Append failed: " << status.ToString() << std::endl;
+    return false;
+  }
+
+  if (dump_options.anonymous) {
+    snprintf(json, sizeof(json), "{}");
+  } else {
+    status = env->GetHostName(hostname, sizeof(hostname));
+    status = env->GetCurrentTime(&timesec);
+    status = env->GetAbsolutePath(dump_options.db_path, &abspath);
+    snprintf(json, sizeof(json),
+             "{ \"database-path\": \"%s\", \"hostname\": \"%s\", "
+             "\"creation-time\": %" PRIi64 " }",
+             abspath.c_str(), hostname, timesec);
+  }
+
+  rocksdb::Slice infoslice(json, strlen(json));
+  char infosize[4];
+  rocksdb::EncodeFixed32(infosize, (uint32_t)infoslice.size());
+  rocksdb::Slice infosizeslice(infosize, 4);
+  status = dumpfile->Append(infosizeslice);
+  if (!status.ok()) {
+    std::cerr << "Append failed: " << status.ToString() << std::endl;
+    return false;
+  }
+  status = dumpfile->Append(infoslice);
+  if (!status.ok()) {
+    std::cerr << "Append failed: " << status.ToString() << std::endl;
+    return false;
+  }
+
+  const std::unique_ptr<rocksdb::Iterator> it(
+      db->NewIterator(rocksdb::ReadOptions()));
+  for (it->SeekToFirst(); it->Valid(); it->Next()) {
+    char keysize[4];
+    rocksdb::EncodeFixed32(keysize, (uint32_t)it->key().size());
+    rocksdb::Slice keysizeslice(keysize, 4);
+    status = dumpfile->Append(keysizeslice);
+    if (!status.ok()) {
+      std::cerr << "Append failed: " << status.ToString() << std::endl;
+      return false;
+    }
+    status = dumpfile->Append(it->key());
+    if (!status.ok()) {
+      std::cerr << "Append failed: " << status.ToString() << std::endl;
+      return false;
+    }
+
+    char valsize[4];
+    rocksdb::EncodeFixed32(valsize, (uint32_t)it->value().size());
+    rocksdb::Slice valsizeslice(valsize, 4);
+    status = dumpfile->Append(valsizeslice);
+    if (!status.ok()) {
+      std::cerr << "Append failed: " << status.ToString() << std::endl;
+      return false;
+    }
+    status = dumpfile->Append(it->value());
+    if (!status.ok()) {
+      std::cerr << "Append failed: " << status.ToString() << std::endl;
+      return false;
+    }
+  }
+  if (!it->status().ok()) {
+    std::cerr << "Database iteration failed: " << status.ToString()
+              << std::endl;
+    return false;
+  }
+  return true;
+}
+
+bool DbUndumpTool::Run(const UndumpOptions& undump_options,
+                       rocksdb::Options options) {
+  rocksdb::DB* dbptr;
+  rocksdb::Status status;
+  rocksdb::Env* env;
+  std::unique_ptr<rocksdb::SequentialFile> dumpfile;
+  rocksdb::Slice slice;
+  char scratch8[8];
+
+  static const char* magicstr = "ROCKDUMP";
+  static const char versionstr[8] = {0, 0, 0, 0, 0, 0, 0, 1};
+
+  env = rocksdb::Env::Default();
+
+  status = env->NewSequentialFile(undump_options.dump_location, &dumpfile,
+                                  rocksdb::EnvOptions());
+  if (!status.ok()) {
+    std::cerr << "Unable to open dump file '" << undump_options.dump_location
+              << "' for reading: " << status.ToString() << std::endl;
+    return false;
+  }
+
+  status = dumpfile->Read(8, &slice, scratch8);
+  if (!status.ok() || slice.size() != 8 ||
+      memcmp(slice.data(), magicstr, 8) != 0) {
+    std::cerr << "File '" << undump_options.dump_location
+              << "' is not a recognizable dump file." << std::endl;
+    return false;
+  }
+
+  status = dumpfile->Read(8, &slice, scratch8);
+  if (!status.ok() || slice.size() != 8 ||
+      memcmp(slice.data(), versionstr, 8) != 0) {
+    std::cerr << "File '" << undump_options.dump_location
+              << "' version not recognized." << std::endl;
+    return false;
+  }
+
+  status = dumpfile->Read(4, &slice, scratch8);
+  if (!status.ok() || slice.size() != 4) {
+    std::cerr << "Unable to read info blob size." << std::endl;
+    return false;
+  }
+  uint32_t infosize = rocksdb::DecodeFixed32(slice.data());
+  status = dumpfile->Skip(infosize);
+  if (!status.ok()) {
+    std::cerr << "Unable to skip info blob: " << status.ToString() << std::endl;
+    return false;
+  }
+
+  options.create_if_missing = true;
+  status = rocksdb::DB::Open(options, undump_options.db_path, &dbptr);
+  if (!status.ok()) {
+    std::cerr << "Unable to open database '" << undump_options.db_path
+              << "' for writing: " << status.ToString() << std::endl;
+    return false;
+  }
+
+  const std::unique_ptr<rocksdb::DB> db(dbptr);
+
+  uint32_t last_keysize = 64;
+  size_t last_valsize = 1 << 20;
+  std::unique_ptr<char[]> keyscratch(new char[last_keysize]);
+  std::unique_ptr<char[]> valscratch(new char[last_valsize]);
+
+  while (1) {
+    uint32_t keysize, valsize;
+    rocksdb::Slice keyslice;
+    rocksdb::Slice valslice;
+
+    status = dumpfile->Read(4, &slice, scratch8);
+    if (!status.ok() || slice.size() != 4) break;
+    keysize = rocksdb::DecodeFixed32(slice.data());
+    if (keysize > last_keysize) {
+      while (keysize > last_keysize) last_keysize *= 2;
+      keyscratch = std::unique_ptr<char[]>(new char[last_keysize]);
+    }
+
+    status = dumpfile->Read(keysize, &keyslice, keyscratch.get());
+    if (!status.ok() || keyslice.size() != keysize) {
+      std::cerr << "Key read failure: "
+                << (status.ok() ? "insufficient data" : status.ToString())
+                << std::endl;
+      return false;
+    }
+
+    status = dumpfile->Read(4, &slice, scratch8);
+    if (!status.ok() || slice.size() != 4) {
+      std::cerr << "Unable to read value size: "
+                << (status.ok() ? "insufficient data" : status.ToString())
+                << std::endl;
+      return false;
+    }
+    valsize = rocksdb::DecodeFixed32(slice.data());
+    if (valsize > last_valsize) {
+      while (valsize > last_valsize) last_valsize *= 2;
+      valscratch = std::unique_ptr<char[]>(new char[last_valsize]);
+    }
+
+    status = dumpfile->Read(valsize, &valslice, valscratch.get());
+    if (!status.ok() || valslice.size() != valsize) {
+      std::cerr << "Unable to read value: "
+                << (status.ok() ? "insufficient data" : status.ToString())
+                << std::endl;
+      return false;
+    }
+
+    status = db->Put(rocksdb::WriteOptions(), keyslice, valslice);
+    if (!status.ok()) {
+      fprintf(stderr, "Unable to write database entry\n");
+      return false;
+    }
+  }
+
+  if (undump_options.compact_db) {
+    status = db->CompactRange(rocksdb::CompactRangeOptions(), nullptr, nullptr);
+    if (!status.ok()) {
+      fprintf(stderr,
+              "Unable to compact the database after loading the dumped file\n");
+      return false;
+    }
+  }
+  return true;
+}
+}  // namespace rocksdb
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/dump/rocksdb_dump.cc b/src/rocksdb/tools/dump/rocksdb_dump.cc
new file mode 100644
index 00000000..249371a2
--- /dev/null
+++ b/src/rocksdb/tools/dump/rocksdb_dump.cc
@@ -0,0 +1,63 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#if !(defined GFLAGS) || defined(ROCKSDB_LITE)
+
+#include <cstdio>
+int main() {
+#ifndef GFLAGS
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+#endif
+#ifdef ROCKSDB_LITE
+  fprintf(stderr, "DbDumpTool is not supported in ROCKSDB_LITE\n");
+#endif
+  return 1;
+}
+
+#else
+
+#include "rocksdb/convenience.h"
+#include "rocksdb/db_dump_tool.h"
+#include "util/gflags_compat.h"
+
+DEFINE_string(db_path, "", "Path to the db that will be dumped");
+DEFINE_string(dump_location, "", "Path to where the dump file location");
+DEFINE_bool(anonymous, false,
+            "Remove information like db path, creation time from dumped file");
+DEFINE_string(db_options, "",
+              "Options string used to open the database that will be dumped");
+
+int main(int argc, char** argv) {
+  GFLAGS_NAMESPACE::ParseCommandLineFlags(&argc, &argv, true);
+
+  if (FLAGS_db_path == "" || FLAGS_dump_location == "") {
+    fprintf(stderr, "Please set --db_path and --dump_location\n");
+    return 1;
+  }
+
+  rocksdb::DumpOptions dump_options;
+  dump_options.db_path = FLAGS_db_path;
+  dump_options.dump_location = FLAGS_dump_location;
+  dump_options.anonymous = FLAGS_anonymous;
+
+  rocksdb::Options db_options;
+  if (FLAGS_db_options != "") {
+    rocksdb::Options parsed_options;
+    rocksdb::Status s = rocksdb::GetOptionsFromString(
+        db_options, FLAGS_db_options, &parsed_options);
+    if (!s.ok()) {
+      fprintf(stderr, "Cannot parse provided db_options\n");
+      return 1;
+    }
+    db_options = parsed_options;
+  }
+
+  rocksdb::DbDumpTool tool;
+  if (!tool.Run(dump_options, db_options)) {
+    return 1;
+  }
+  return 0;
+}
+#endif  // !(defined GFLAGS) || defined(ROCKSDB_LITE)
diff --git a/src/rocksdb/tools/dump/rocksdb_undump.cc b/src/rocksdb/tools/dump/rocksdb_undump.cc
new file mode 100644
index 00000000..450c7e47
--- /dev/null
+++ b/src/rocksdb/tools/dump/rocksdb_undump.cc
@@ -0,0 +1,62 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#if !(defined GFLAGS) || defined(ROCKSDB_LITE)
+
+#include <cstdio>
+int main() {
+#ifndef GFLAGS
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+#endif
+#ifdef ROCKSDB_LITE
+  fprintf(stderr, "DbUndumpTool is not supported in ROCKSDB_LITE\n");
+#endif
+  return 1;
+}
+
+#else
+
+#include "rocksdb/convenience.h"
+#include "rocksdb/db_dump_tool.h"
+#include "util/gflags_compat.h"
+
+DEFINE_string(dump_location, "", "Path to the dump file that will be loaded");
+DEFINE_string(db_path, "", "Path to the db that we will undump the file into");
+DEFINE_bool(compact, false, "Compact the db after loading the dumped file");
+DEFINE_string(db_options, "",
+              "Options string used to open the database that will be loaded");
+
+int main(int argc, char **argv) {
+  GFLAGS_NAMESPACE::ParseCommandLineFlags(&argc, &argv, true);
+
+  if (FLAGS_db_path == "" || FLAGS_dump_location == "") {
+    fprintf(stderr, "Please set --db_path and --dump_location\n");
+    return 1;
+  }
+
+  rocksdb::UndumpOptions undump_options;
+  undump_options.db_path = FLAGS_db_path;
+  undump_options.dump_location = FLAGS_dump_location;
+  undump_options.compact_db = FLAGS_compact;
+
+  rocksdb::Options db_options;
+  if (FLAGS_db_options != "") {
+    rocksdb::Options parsed_options;
+    rocksdb::Status s = rocksdb::GetOptionsFromString(
+        db_options, FLAGS_db_options, &parsed_options);
+    if (!s.ok()) {
+      fprintf(stderr, "Cannot parse provided db_options\n");
+      return 1;
+    }
+    db_options = parsed_options;
+  }
+
+  rocksdb::DbUndumpTool tool;
+  if (!tool.Run(undump_options, db_options)) {
+    return 1;
+  }
+  return 0;
+}
+#endif  // !(defined GFLAGS) || defined(ROCKSDB_LITE)
diff --git a/src/rocksdb/tools/generate_random_db.sh b/src/rocksdb/tools/generate_random_db.sh
new file mode 100755
index 00000000..e10843ba
--- /dev/null
+++ b/src/rocksdb/tools/generate_random_db.sh
@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+#
+# A shell script to load some pre generated data file to a DB using ldb tool
+# ./ldb needs to be avaible to be executed.
+#
+# Usage: <SCRIPT> <input_data_path> <DB Path>
+
+if [ "$#" -lt 2 ]; then
+  echo "usage: $BASH_SOURCE <input_data_path> <DB Path>"
+  exit 1
+fi
+
+input_data_dir=$1
+db_dir=$2
+rm -rf $db_dir
+
+echo == Loading data from $input_data_dir to $db_dir
+
+declare -a compression_opts=("no" "snappy" "zlib" "bzip2")
+
+set -e
+
+n=0
+
+for f in `ls -1 $input_data_dir`
+do
+  echo == Loading $f with compression ${compression_opts[n % 4]}
+  ./ldb load --db=$db_dir --compression_type=${compression_opts[n % 4]} --bloom_bits=10 --auto_compaction=false --create_if_missing < $input_data_dir/$f
+  let "n = n + 1"
+done
diff --git a/src/rocksdb/tools/ingest_external_sst.sh b/src/rocksdb/tools/ingest_external_sst.sh
new file mode 100755
index 00000000..54ca3db3
--- /dev/null
+++ b/src/rocksdb/tools/ingest_external_sst.sh
@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+#
+#
+
+if [ "$#" -lt 2 ]; then
+  echo "usage: $BASH_SOURCE <DB Path> <External SST Dir>"
+  exit 1
+fi
+
+db_dir=$1
+external_sst_dir=$2
+
+for f in `find $external_sst_dir -name extern_sst*`
+do
+  echo == Ingesting external SST file $f to DB at $db_dir
+  ./ldb --db=$db_dir --create_if_missing ingest_extern_sst $f
+done
diff --git a/src/rocksdb/tools/ldb.cc b/src/rocksdb/tools/ldb.cc
new file mode 100644
index 00000000..83193132
--- /dev/null
+++ b/src/rocksdb/tools/ldb.cc
@@ -0,0 +1,21 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+#ifndef ROCKSDB_LITE
+
+#include "rocksdb/ldb_tool.h"
+
+int main(int argc, char** argv) {
+  rocksdb::LDBTool tool;
+  tool.Run(argc, argv);
+  return 0;
+}
+#else
+#include <stdio.h>
+int main(int /*argc*/, char** /*argv*/) {
+  fprintf(stderr, "Not supported in lite mode.\n");
+  return 1;
+}
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/ldb_cmd.cc b/src/rocksdb/tools/ldb_cmd.cc
new file mode 100644
index 00000000..e106bfbb
--- /dev/null
+++ b/src/rocksdb/tools/ldb_cmd.cc
@@ -0,0 +1,3164 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+#ifndef ROCKSDB_LITE
+#include "rocksdb/utilities/ldb_cmd.h"
+
+#ifndef __STDC_FORMAT_MACROS
+#define __STDC_FORMAT_MACROS
+#endif
+
+#include <inttypes.h>
+
+#include "db/db_impl.h"
+#include "db/dbformat.h"
+#include "db/log_reader.h"
+#include "db/write_batch_internal.h"
+#include "port/port_dirent.h"
+#include "rocksdb/cache.h"
+#include "rocksdb/table_properties.h"
+#include "rocksdb/utilities/backupable_db.h"
+#include "rocksdb/utilities/checkpoint.h"
+#include "rocksdb/utilities/debug.h"
+#include "rocksdb/utilities/object_registry.h"
+#include "rocksdb/utilities/options_util.h"
+#include "rocksdb/write_batch.h"
+#include "rocksdb/write_buffer_manager.h"
+#include "table/scoped_arena_iterator.h"
+#include "tools/ldb_cmd_impl.h"
+#include "tools/sst_dump_tool_imp.h"
+#include "util/cast_util.h"
+#include "util/coding.h"
+#include "util/filename.h"
+#include "util/stderr_logger.h"
+#include "util/string_util.h"
+#include "utilities/ttl/db_ttl_impl.h"
+
+#include <cstdlib>
+#include <ctime>
+#include <fstream>
+#include <functional>
+#include <iostream>
+#include <limits>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+
+namespace rocksdb {
+
+const std::string LDBCommand::ARG_DB = "db";
+const std::string LDBCommand::ARG_PATH = "path";
+const std::string LDBCommand::ARG_HEX = "hex";
+const std::string LDBCommand::ARG_KEY_HEX = "key_hex";
+const std::string LDBCommand::ARG_VALUE_HEX = "value_hex";
+const std::string LDBCommand::ARG_CF_NAME = "column_family";
+const std::string LDBCommand::ARG_TTL = "ttl";
+const std::string LDBCommand::ARG_TTL_START = "start_time";
+const std::string LDBCommand::ARG_TTL_END = "end_time";
+const std::string LDBCommand::ARG_TIMESTAMP = "timestamp";
+const std::string LDBCommand::ARG_TRY_LOAD_OPTIONS = "try_load_options";
+const std::string LDBCommand::ARG_IGNORE_UNKNOWN_OPTIONS =
+    "ignore_unknown_options";
+const std::string LDBCommand::ARG_FROM = "from";
+const std::string LDBCommand::ARG_TO = "to";
+const std::string LDBCommand::ARG_MAX_KEYS = "max_keys";
+const std::string LDBCommand::ARG_BLOOM_BITS = "bloom_bits";
+const std::string LDBCommand::ARG_FIX_PREFIX_LEN = "fix_prefix_len";
+const std::string LDBCommand::ARG_COMPRESSION_TYPE = "compression_type";
+const std::string LDBCommand::ARG_COMPRESSION_MAX_DICT_BYTES =
+    "compression_max_dict_bytes";
+const std::string LDBCommand::ARG_BLOCK_SIZE = "block_size";
+const std::string LDBCommand::ARG_AUTO_COMPACTION = "auto_compaction";
+const std::string LDBCommand::ARG_DB_WRITE_BUFFER_SIZE = "db_write_buffer_size";
+const std::string LDBCommand::ARG_WRITE_BUFFER_SIZE = "write_buffer_size";
+const std::string LDBCommand::ARG_FILE_SIZE = "file_size";
+const std::string LDBCommand::ARG_CREATE_IF_MISSING = "create_if_missing";
+const std::string LDBCommand::ARG_NO_VALUE = "no_value";
+
+const char* LDBCommand::DELIM = " ==> ";
+
+namespace {
+
+void DumpWalFile(Options options, std::string wal_file, bool print_header,
+                 bool print_values, bool is_write_committed,
+                 LDBCommandExecuteResult* exec_state);
+
+void DumpSstFile(Options options, std::string filename, bool output_hex,
+                 bool show_properties);
+};
+
+LDBCommand* LDBCommand::InitFromCmdLineArgs(
+    int argc, char** argv, const Options& options,
+    const LDBOptions& ldb_options,
+    const std::vector<ColumnFamilyDescriptor>* column_families) {
+  std::vector<std::string> args;
+  for (int i = 1; i < argc; i++) {
+    args.push_back(argv[i]);
+  }
+  return InitFromCmdLineArgs(args, options, ldb_options, column_families,
+                             SelectCommand);
+}
+
+/**
+ * Parse the command-line arguments and create the appropriate LDBCommand2
+ * instance.
+ * The command line arguments must be in the following format:
+ * ./ldb --db=PATH_TO_DB [--commonOpt1=commonOpt1Val] ..
+ *        COMMAND <PARAM1> <PARAM2> ... [-cmdSpecificOpt1=cmdSpecificOpt1Val] ..
+ * This is similar to the command line format used by HBaseClientTool.
+ * Command name is not included in args.
+ * Returns nullptr if the command-line cannot be parsed.
+ */
+LDBCommand* LDBCommand::InitFromCmdLineArgs(
+    const std::vector<std::string>& args, const Options& options,
+    const LDBOptions& ldb_options,
+    const std::vector<ColumnFamilyDescriptor>* /*column_families*/,
+    const std::function<LDBCommand*(const ParsedParams&)>& selector) {
+  // --x=y command line arguments are added as x->y map entries in
+  // parsed_params.option_map.
+  //
+  // Command-line arguments of the form --hex end up in this array as hex to
+  // parsed_params.flags
+  ParsedParams parsed_params;
+
+  // Everything other than option_map and flags. Represents commands
+  // and their parameters.  For eg: put key1 value1 go into this vector.
+  std::vector<std::string> cmdTokens;
+
+  const std::string OPTION_PREFIX = "--";
+
+  for (const auto& arg : args) {
+    if (arg[0] == '-' && arg[1] == '-'){
+      std::vector<std::string> splits = StringSplit(arg, '=');
+      // --option_name=option_value
+      if (splits.size() == 2) {
+        std::string optionKey = splits[0].substr(OPTION_PREFIX.size());
+        parsed_params.option_map[optionKey] = splits[1];
+      } else if (splits.size() == 1) {
+        // --flag_name
+        std::string optionKey = splits[0].substr(OPTION_PREFIX.size());
+        parsed_params.flags.push_back(optionKey);
+      } else {
+        // --option_name=option_value, option_value contains '='
+        std::string optionKey = splits[0].substr(OPTION_PREFIX.size());
+        parsed_params.option_map[optionKey] =
+            arg.substr(splits[0].length() + 1);
+      }
+    } else {
+      cmdTokens.push_back(arg);
+    }
+  }
+
+  if (cmdTokens.size() < 1) {
+    fprintf(stderr, "Command not specified!");
+    return nullptr;
+  }
+
+  parsed_params.cmd = cmdTokens[0];
+  parsed_params.cmd_params.assign(cmdTokens.begin() + 1, cmdTokens.end());
+
+  LDBCommand* command = selector(parsed_params);
+
+  if (command) {
+    command->SetDBOptions(options);
+    command->SetLDBOptions(ldb_options);
+  }
+  return command;
+}
+
+LDBCommand* LDBCommand::SelectCommand(const ParsedParams& parsed_params) {
+  if (parsed_params.cmd == GetCommand::Name()) {
+    return new GetCommand(parsed_params.cmd_params, parsed_params.option_map,
+                          parsed_params.flags);
+  } else if (parsed_params.cmd == PutCommand::Name()) {
+    return new PutCommand(parsed_params.cmd_params, parsed_params.option_map,
+                          parsed_params.flags);
+  } else if (parsed_params.cmd == BatchPutCommand::Name()) {
+    return new BatchPutCommand(parsed_params.cmd_params,
+                               parsed_params.option_map, parsed_params.flags);
+  } else if (parsed_params.cmd == ScanCommand::Name()) {
+    return new ScanCommand(parsed_params.cmd_params, parsed_params.option_map,
+                           parsed_params.flags);
+  } else if (parsed_params.cmd == DeleteCommand::Name()) {
+    return new DeleteCommand(parsed_params.cmd_params, parsed_params.option_map,
+                             parsed_params.flags);
+  } else if (parsed_params.cmd == DeleteRangeCommand::Name()) {
+    return new DeleteRangeCommand(parsed_params.cmd_params,
+                                  parsed_params.option_map,
+                                  parsed_params.flags);
+  } else if (parsed_params.cmd == ApproxSizeCommand::Name()) {
+    return new ApproxSizeCommand(parsed_params.cmd_params,
+                                 parsed_params.option_map, parsed_params.flags);
+  } else if (parsed_params.cmd == DBQuerierCommand::Name()) {
+    return new DBQuerierCommand(parsed_params.cmd_params,
+                                parsed_params.option_map, parsed_params.flags);
+  } else if (parsed_params.cmd == CompactorCommand::Name()) {
+    return new CompactorCommand(parsed_params.cmd_params,
+                                parsed_params.option_map, parsed_params.flags);
+  } else if (parsed_params.cmd == WALDumperCommand::Name()) {
+    return new WALDumperCommand(parsed_params.cmd_params,
+                                parsed_params.option_map, parsed_params.flags);
+  } else if (parsed_params.cmd == ReduceDBLevelsCommand::Name()) {
+    return new ReduceDBLevelsCommand(parsed_params.cmd_params,
+                                     parsed_params.option_map,
+                                     parsed_params.flags);
+  } else if (parsed_params.cmd == ChangeCompactionStyleCommand::Name()) {
+    return new ChangeCompactionStyleCommand(parsed_params.cmd_params,
+                                            parsed_params.option_map,
+                                            parsed_params.flags);
+  } else if (parsed_params.cmd == DBDumperCommand::Name()) {
+    return new DBDumperCommand(parsed_params.cmd_params,
+                               parsed_params.option_map, parsed_params.flags);
+  } else if (parsed_params.cmd == DBLoaderCommand::Name()) {
+    return new DBLoaderCommand(parsed_params.cmd_params,
+                               parsed_params.option_map, parsed_params.flags);
+  } else if (parsed_params.cmd == ManifestDumpCommand::Name()) {
+    return new ManifestDumpCommand(parsed_params.cmd_params,
+                                   parsed_params.option_map,
+                                   parsed_params.flags);
+  } else if (parsed_params.cmd == ListColumnFamiliesCommand::Name()) {
+    return new ListColumnFamiliesCommand(parsed_params.cmd_params,
+                                         parsed_params.option_map,
+                                         parsed_params.flags);
+  } else if (parsed_params.cmd == CreateColumnFamilyCommand::Name()) {
+    return new CreateColumnFamilyCommand(parsed_params.cmd_params,
+                                         parsed_params.option_map,
+                                         parsed_params.flags);
+  } else if (parsed_params.cmd == DBFileDumperCommand::Name()) {
+    return new DBFileDumperCommand(parsed_params.cmd_params,
+                                   parsed_params.option_map,
+                                   parsed_params.flags);
+  } else if (parsed_params.cmd == InternalDumpCommand::Name()) {
+    return new InternalDumpCommand(parsed_params.cmd_params,
+                                   parsed_params.option_map,
+                                   parsed_params.flags);
+  } else if (parsed_params.cmd == CheckConsistencyCommand::Name()) {
+    return new CheckConsistencyCommand(parsed_params.cmd_params,
+                                       parsed_params.option_map,
+                                       parsed_params.flags);
+  } else if (parsed_params.cmd == CheckPointCommand::Name()) {
+    return new CheckPointCommand(parsed_params.cmd_params,
+                                 parsed_params.option_map,
+                                 parsed_params.flags);
+  } else if (parsed_params.cmd == RepairCommand::Name()) {
+    return new RepairCommand(parsed_params.cmd_params, parsed_params.option_map,
+                             parsed_params.flags);
+  } else if (parsed_params.cmd == BackupCommand::Name()) {
+    return new BackupCommand(parsed_params.cmd_params, parsed_params.option_map,
+                             parsed_params.flags);
+  } else if (parsed_params.cmd == RestoreCommand::Name()) {
+    return new RestoreCommand(parsed_params.cmd_params,
+                              parsed_params.option_map, parsed_params.flags);
+  } else if (parsed_params.cmd == WriteExternalSstFilesCommand::Name()) {
+    return new WriteExternalSstFilesCommand(parsed_params.cmd_params,
+                                            parsed_params.option_map,
+                                            parsed_params.flags);
+  } else if (parsed_params.cmd == IngestExternalSstFilesCommand::Name()) {
+    return new IngestExternalSstFilesCommand(parsed_params.cmd_params,
+                                             parsed_params.option_map,
+                                             parsed_params.flags);
+  }
+  return nullptr;
+}
+
+/* Run the command, and return the execute result. */
+void LDBCommand::Run() {
+  if (!exec_state_.IsNotStarted()) {
+    return;
+  }
+
+  if (db_ == nullptr && !NoDBOpen()) {
+    OpenDB();
+    if (exec_state_.IsFailed() && try_load_options_) {
+      // We don't always return if there is a failure because a WAL file or
+      // manifest file can be given to "dump" command so we should continue.
+      // --try_load_options is not valid in those cases.
+      return;
+    }
+  }
+
+  // We'll intentionally proceed even if the DB can't be opened because users
+  // can also specify a filename, not just a directory.
+  DoCommand();
+
+  if (exec_state_.IsNotStarted()) {
+    exec_state_ = LDBCommandExecuteResult::Succeed("");
+  }
+
+  if (db_ != nullptr) {
+    CloseDB();
+  }
+}
+
+LDBCommand::LDBCommand(const std::map<std::string, std::string>& options,
+                       const std::vector<std::string>& flags, bool is_read_only,
+                       const std::vector<std::string>& valid_cmd_line_options)
+    : db_(nullptr),
+      db_ttl_(nullptr),
+      is_read_only_(is_read_only),
+      is_key_hex_(false),
+      is_value_hex_(false),
+      is_db_ttl_(false),
+      timestamp_(false),
+      try_load_options_(false),
+      ignore_unknown_options_(false),
+      create_if_missing_(false),
+      option_map_(options),
+      flags_(flags),
+      valid_cmd_line_options_(valid_cmd_line_options) {
+  std::map<std::string, std::string>::const_iterator itr = options.find(ARG_DB);
+  if (itr != options.end()) {
+    db_path_ = itr->second;
+  }
+
+  itr = options.find(ARG_CF_NAME);
+  if (itr != options.end()) {
+    column_family_name_ = itr->second;
+  } else {
+    column_family_name_ = kDefaultColumnFamilyName;
+  }
+
+  is_key_hex_ = IsKeyHex(options, flags);
+  is_value_hex_ = IsValueHex(options, flags);
+  is_db_ttl_ = IsFlagPresent(flags, ARG_TTL);
+  timestamp_ = IsFlagPresent(flags, ARG_TIMESTAMP);
+  try_load_options_ = IsFlagPresent(flags, ARG_TRY_LOAD_OPTIONS);
+  ignore_unknown_options_ = IsFlagPresent(flags, ARG_IGNORE_UNKNOWN_OPTIONS);
+}
+
+void LDBCommand::OpenDB() {
+  if (!create_if_missing_ && try_load_options_) {
+    Status s = LoadLatestOptions(db_path_, Env::Default(), &options_,
+                                 &column_families_, ignore_unknown_options_);
+    if (!s.ok() && !s.IsNotFound()) {
+      // Option file exists but load option file error.
+      std::string msg = s.ToString();
+      exec_state_ = LDBCommandExecuteResult::Failed(msg);
+      db_ = nullptr;
+      return;
+    }
+    if (options_.env->FileExists(options_.wal_dir).IsNotFound()) {
+      options_.wal_dir = db_path_;
+      fprintf(
+          stderr,
+          "wal_dir loaded from the option file doesn't exist. Ignore it.\n");
+    }
+  }
+  options_ = PrepareOptionsForOpenDB();
+  if (!exec_state_.IsNotStarted()) {
+    return;
+  }
+  // Open the DB.
+  Status st;
+  std::vector<ColumnFamilyHandle*> handles_opened;
+  if (is_db_ttl_) {
+    // ldb doesn't yet support TTL DB with multiple column families
+    if (!column_family_name_.empty() || !column_families_.empty()) {
+      exec_state_ = LDBCommandExecuteResult::Failed(
+          "ldb doesn't support TTL DB with multiple column families");
+    }
+    if (is_read_only_) {
+      st = DBWithTTL::Open(options_, db_path_, &db_ttl_, 0, true);
+    } else {
+      st = DBWithTTL::Open(options_, db_path_, &db_ttl_);
+    }
+    db_ = db_ttl_;
+  } else {
+    if (column_families_.empty()) {
+      // Try to figure out column family lists
+      std::vector<std::string> cf_list;
+      st = DB::ListColumnFamilies(DBOptions(), db_path_, &cf_list);
+      // There is possible the DB doesn't exist yet, for "create if not
+      // "existing case". The failure is ignored here. We rely on DB::Open()
+      // to give us the correct error message for problem with opening
+      // existing DB.
+      if (st.ok() && cf_list.size() > 1) {
+        // Ignore single column family DB.
+        for (auto cf_name : cf_list) {
+          column_families_.emplace_back(cf_name, options_);
+        }
+      }
+    }
+    if (is_read_only_) {
+      if (column_families_.empty()) {
+        st = DB::OpenForReadOnly(options_, db_path_, &db_);
+      } else {
+        st = DB::OpenForReadOnly(options_, db_path_, column_families_,
+                                 &handles_opened, &db_);
+      }
+    } else {
+      if (column_families_.empty()) {
+        st = DB::Open(options_, db_path_, &db_);
+      } else {
+        st = DB::Open(options_, db_path_, column_families_, &handles_opened,
+                      &db_);
+      }
+    }
+  }
+  if (!st.ok()) {
+    std::string msg = st.ToString();
+    exec_state_ = LDBCommandExecuteResult::Failed(msg);
+  } else if (!handles_opened.empty()) {
+    assert(handles_opened.size() == column_families_.size());
+    bool found_cf_name = false;
+    for (size_t i = 0; i < handles_opened.size(); i++) {
+      cf_handles_[column_families_[i].name] = handles_opened[i];
+      if (column_family_name_ == column_families_[i].name) {
+        found_cf_name = true;
+      }
+    }
+    if (!found_cf_name) {
+      exec_state_ = LDBCommandExecuteResult::Failed(
+          "Non-existing column family " + column_family_name_);
+      CloseDB();
+    }
+  } else {
+    // We successfully opened DB in single column family mode.
+    assert(column_families_.empty());
+    if (column_family_name_ != kDefaultColumnFamilyName) {
+      exec_state_ = LDBCommandExecuteResult::Failed(
+          "Non-existing column family " + column_family_name_);
+      CloseDB();
+    }
+  }
+}
+
+void LDBCommand::CloseDB() {
+  if (db_ != nullptr) {
+    for (auto& pair : cf_handles_) {
+      delete pair.second;
+    }
+    delete db_;
+    db_ = nullptr;
+  }
+}
+
+ColumnFamilyHandle* LDBCommand::GetCfHandle() {
+  if (!cf_handles_.empty()) {
+    auto it = cf_handles_.find(column_family_name_);
+    if (it == cf_handles_.end()) {
+      exec_state_ = LDBCommandExecuteResult::Failed(
+          "Cannot find column family " + column_family_name_);
+    } else {
+      return it->second;
+    }
+  }
+  return db_->DefaultColumnFamily();
+}
+
+std::vector<std::string> LDBCommand::BuildCmdLineOptions(
+    std::vector<std::string> options) {
+  std::vector<std::string> ret = {ARG_DB,
+                                  ARG_BLOOM_BITS,
+                                  ARG_BLOCK_SIZE,
+                                  ARG_AUTO_COMPACTION,
+                                  ARG_COMPRESSION_TYPE,
+                                  ARG_COMPRESSION_MAX_DICT_BYTES,
+                                  ARG_WRITE_BUFFER_SIZE,
+                                  ARG_FILE_SIZE,
+                                  ARG_FIX_PREFIX_LEN,
+                                  ARG_TRY_LOAD_OPTIONS,
+                                  ARG_IGNORE_UNKNOWN_OPTIONS,
+                                  ARG_CF_NAME};
+  ret.insert(ret.end(), options.begin(), options.end());
+  return ret;
+}
+
+/**
+ * Parses the specific integer option and fills in the value.
+ * Returns true if the option is found.
+ * Returns false if the option is not found or if there is an error parsing the
+ * value.  If there is an error, the specified exec_state is also
+ * updated.
+ */
+bool LDBCommand::ParseIntOption(
+    const std::map<std::string, std::string>& /*options*/,
+    const std::string& option, int& value,
+    LDBCommandExecuteResult& exec_state) {
+  std::map<std::string, std::string>::const_iterator itr =
+      option_map_.find(option);
+  if (itr != option_map_.end()) {
+    try {
+#if defined(CYGWIN)
+      value = strtol(itr->second.c_str(), 0, 10);
+#else
+      value = std::stoi(itr->second);
+#endif
+      return true;
+    } catch (const std::invalid_argument&) {
+      exec_state =
+          LDBCommandExecuteResult::Failed(option + " has an invalid value.");
+    } catch (const std::out_of_range&) {
+      exec_state = LDBCommandExecuteResult::Failed(
+          option + " has a value out-of-range.");
+    }
+  }
+  return false;
+}
+
+/**
+ * Parses the specified option and fills in the value.
+ * Returns true if the option is found.
+ * Returns false otherwise.
+ */
+bool LDBCommand::ParseStringOption(
+    const std::map<std::string, std::string>& /*options*/,
+    const std::string& option, std::string* value) {
+  auto itr = option_map_.find(option);
+  if (itr != option_map_.end()) {
+    *value = itr->second;
+    return true;
+  }
+  return false;
+}
+
+Options LDBCommand::PrepareOptionsForOpenDB() {
+  ColumnFamilyOptions* cf_opts;
+  auto column_families_iter =
+      std::find_if(column_families_.begin(), column_families_.end(),
+                   [this](const ColumnFamilyDescriptor& cf_desc) {
+                     return cf_desc.name == column_family_name_;
+                   });
+  if (column_families_iter != column_families_.end()) {
+    cf_opts = &column_families_iter->options;
+  } else {
+    cf_opts = static_cast<ColumnFamilyOptions*>(&options_);
+  }
+  DBOptions* db_opts = static_cast<DBOptions*>(&options_);
+  db_opts->create_if_missing = false;
+
+  std::map<std::string, std::string>::const_iterator itr;
+
+  BlockBasedTableOptions table_options;
+  bool use_table_options = false;
+  int bits;
+  if (ParseIntOption(option_map_, ARG_BLOOM_BITS, bits, exec_state_)) {
+    if (bits > 0) {
+      use_table_options = true;
+      table_options.filter_policy.reset(NewBloomFilterPolicy(bits));
+    } else {
+      exec_state_ =
+          LDBCommandExecuteResult::Failed(ARG_BLOOM_BITS + " must be > 0.");
+    }
+  }
+
+  int block_size;
+  if (ParseIntOption(option_map_, ARG_BLOCK_SIZE, block_size, exec_state_)) {
+    if (block_size > 0) {
+      use_table_options = true;
+      table_options.block_size = block_size;
+    } else {
+      exec_state_ =
+          LDBCommandExecuteResult::Failed(ARG_BLOCK_SIZE + " must be > 0.");
+    }
+  }
+
+  if (use_table_options) {
+    cf_opts->table_factory.reset(NewBlockBasedTableFactory(table_options));
+  }
+
+  itr = option_map_.find(ARG_AUTO_COMPACTION);
+  if (itr != option_map_.end()) {
+    cf_opts->disable_auto_compactions = !StringToBool(itr->second);
+  }
+
+  itr = option_map_.find(ARG_COMPRESSION_TYPE);
+  if (itr != option_map_.end()) {
+    std::string comp = itr->second;
+    if (comp == "no") {
+      cf_opts->compression = kNoCompression;
+    } else if (comp == "snappy") {
+      cf_opts->compression = kSnappyCompression;
+    } else if (comp == "zlib") {
+      cf_opts->compression = kZlibCompression;
+    } else if (comp == "bzip2") {
+      cf_opts->compression = kBZip2Compression;
+    } else if (comp == "lz4") {
+      cf_opts->compression = kLZ4Compression;
+    } else if (comp == "lz4hc") {
+      cf_opts->compression = kLZ4HCCompression;
+    } else if (comp == "xpress") {
+      cf_opts->compression = kXpressCompression;
+    } else if (comp == "zstd") {
+      cf_opts->compression = kZSTD;
+    } else {
+      // Unknown compression.
+      exec_state_ =
+          LDBCommandExecuteResult::Failed("Unknown compression level: " + comp);
+    }
+  }
+
+  int compression_max_dict_bytes;
+  if (ParseIntOption(option_map_, ARG_COMPRESSION_MAX_DICT_BYTES,
+                     compression_max_dict_bytes, exec_state_)) {
+    if (compression_max_dict_bytes >= 0) {
+      cf_opts->compression_opts.max_dict_bytes = compression_max_dict_bytes;
+    } else {
+      exec_state_ = LDBCommandExecuteResult::Failed(
+          ARG_COMPRESSION_MAX_DICT_BYTES + " must be >= 0.");
+    }
+  }
+
+  int db_write_buffer_size;
+  if (ParseIntOption(option_map_, ARG_DB_WRITE_BUFFER_SIZE,
+        db_write_buffer_size, exec_state_)) {
+    if (db_write_buffer_size >= 0) {
+      db_opts->db_write_buffer_size = db_write_buffer_size;
+    } else {
+      exec_state_ = LDBCommandExecuteResult::Failed(ARG_DB_WRITE_BUFFER_SIZE +
+                                                    " must be >= 0.");
+    }
+  }
+
+  int write_buffer_size;
+  if (ParseIntOption(option_map_, ARG_WRITE_BUFFER_SIZE, write_buffer_size,
+        exec_state_)) {
+    if (write_buffer_size > 0) {
+      cf_opts->write_buffer_size = write_buffer_size;
+    } else {
+      exec_state_ = LDBCommandExecuteResult::Failed(ARG_WRITE_BUFFER_SIZE +
+                                                    " must be > 0.");
+    }
+  }
+
+  int file_size;
+  if (ParseIntOption(option_map_, ARG_FILE_SIZE, file_size, exec_state_)) {
+    if (file_size > 0) {
+      cf_opts->target_file_size_base = file_size;
+    } else {
+      exec_state_ =
+          LDBCommandExecuteResult::Failed(ARG_FILE_SIZE + " must be > 0.");
+    }
+  }
+
+  if (db_opts->db_paths.size() == 0) {
+    db_opts->db_paths.emplace_back(db_path_,
+                                   std::numeric_limits<uint64_t>::max());
+  }
+
+  int fix_prefix_len;
+  if (ParseIntOption(option_map_, ARG_FIX_PREFIX_LEN, fix_prefix_len,
+                     exec_state_)) {
+    if (fix_prefix_len > 0) {
+      cf_opts->prefix_extractor.reset(
+          NewFixedPrefixTransform(static_cast<size_t>(fix_prefix_len)));
+    } else {
+      exec_state_ =
+          LDBCommandExecuteResult::Failed(ARG_FIX_PREFIX_LEN + " must be > 0.");
+    }
+  }
+  // TODO(ajkr): this return value doesn't reflect the CF options changed, so
+  // subcommands that rely on this won't see the effect of CF-related CLI args.
+  // Such subcommands need to be changed to properly support CFs.
+  return options_;
+}
+
+bool LDBCommand::ParseKeyValue(const std::string& line, std::string* key,
+                               std::string* value, bool is_key_hex,
+                               bool is_value_hex) {
+  size_t pos = line.find(DELIM);
+  if (pos != std::string::npos) {
+    *key = line.substr(0, pos);
+    *value = line.substr(pos + strlen(DELIM));
+    if (is_key_hex) {
+      *key = HexToString(*key);
+    }
+    if (is_value_hex) {
+      *value = HexToString(*value);
+    }
+    return true;
+  } else {
+    return false;
+  }
+}
+
+/**
+ * Make sure that ONLY the command-line options and flags expected by this
+ * command are specified on the command-line.  Extraneous options are usually
+ * the result of user error.
+ * Returns true if all checks pass.  Else returns false, and prints an
+ * appropriate error msg to stderr.
+ */
+bool LDBCommand::ValidateCmdLineOptions() {
+  for (std::map<std::string, std::string>::const_iterator itr =
+           option_map_.begin();
+       itr != option_map_.end(); ++itr) {
+    if (std::find(valid_cmd_line_options_.begin(),
+                  valid_cmd_line_options_.end(),
+                  itr->first) == valid_cmd_line_options_.end()) {
+      fprintf(stderr, "Invalid command-line option %s\n", itr->first.c_str());
+      return false;
+    }
+  }
+
+  for (std::vector<std::string>::const_iterator itr = flags_.begin();
+       itr != flags_.end(); ++itr) {
+    if (std::find(valid_cmd_line_options_.begin(),
+                  valid_cmd_line_options_.end(),
+                  *itr) == valid_cmd_line_options_.end()) {
+      fprintf(stderr, "Invalid command-line flag %s\n", itr->c_str());
+      return false;
+    }
+  }
+
+  if (!NoDBOpen() && option_map_.find(ARG_DB) == option_map_.end() &&
+      option_map_.find(ARG_PATH) == option_map_.end()) {
+    fprintf(stderr, "Either %s or %s must be specified.\n", ARG_DB.c_str(),
+            ARG_PATH.c_str());
+    return false;
+  }
+
+  return true;
+}
+
+std::string LDBCommand::HexToString(const std::string& str) {
+  std::string result;
+  std::string::size_type len = str.length();
+  if (len < 2 || str[0] != '0' || str[1] != 'x') {
+    fprintf(stderr, "Invalid hex input %s.  Must start with 0x\n", str.c_str());
+    throw "Invalid hex input";
+  }
+  if (!Slice(str.data() + 2, len - 2).DecodeHex(&result)) {
+    throw "Invalid hex input";
+  }
+  return result;
+}
+
+std::string LDBCommand::StringToHex(const std::string& str) {
+  std::string result("0x");
+  result.append(Slice(str).ToString(true));
+  return result;
+}
+
+std::string LDBCommand::PrintKeyValue(const std::string& key,
+                                      const std::string& value, bool is_key_hex,
+                                      bool is_value_hex) {
+  std::string result;
+  result.append(is_key_hex ? StringToHex(key) : key);
+  result.append(DELIM);
+  result.append(is_value_hex ? StringToHex(value) : value);
+  return result;
+}
+
+std::string LDBCommand::PrintKeyValue(const std::string& key,
+                                      const std::string& value, bool is_hex) {
+  return PrintKeyValue(key, value, is_hex, is_hex);
+}
+
+std::string LDBCommand::HelpRangeCmdArgs() {
+  std::ostringstream str_stream;
+  str_stream << " ";
+  str_stream << "[--" << ARG_FROM << "] ";
+  str_stream << "[--" << ARG_TO << "] ";
+  return str_stream.str();
+}
+
+bool LDBCommand::IsKeyHex(const std::map<std::string, std::string>& options,
+                          const std::vector<std::string>& flags) {
+  return (IsFlagPresent(flags, ARG_HEX) || IsFlagPresent(flags, ARG_KEY_HEX) ||
+          ParseBooleanOption(options, ARG_HEX, false) ||
+          ParseBooleanOption(options, ARG_KEY_HEX, false));
+}
+
+bool LDBCommand::IsValueHex(const std::map<std::string, std::string>& options,
+                            const std::vector<std::string>& flags) {
+  return (IsFlagPresent(flags, ARG_HEX) ||
+          IsFlagPresent(flags, ARG_VALUE_HEX) ||
+          ParseBooleanOption(options, ARG_HEX, false) ||
+          ParseBooleanOption(options, ARG_VALUE_HEX, false));
+}
+
+bool LDBCommand::ParseBooleanOption(
+    const std::map<std::string, std::string>& options,
+    const std::string& option, bool default_val) {
+  std::map<std::string, std::string>::const_iterator itr = options.find(option);
+  if (itr != options.end()) {
+    std::string option_val = itr->second;
+    return StringToBool(itr->second);
+  }
+  return default_val;
+}
+
+bool LDBCommand::StringToBool(std::string val) {
+  std::transform(val.begin(), val.end(), val.begin(),
+                 [](char ch) -> char { return (char)::tolower(ch); });
+
+  if (val == "true") {
+    return true;
+  } else if (val == "false") {
+    return false;
+  } else {
+    throw "Invalid value for boolean argument";
+  }
+}
+
+CompactorCommand::CompactorCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false,
+                 BuildCmdLineOptions({ARG_FROM, ARG_TO, ARG_HEX, ARG_KEY_HEX,
+                                      ARG_VALUE_HEX, ARG_TTL})),
+      null_from_(true),
+      null_to_(true) {
+  std::map<std::string, std::string>::const_iterator itr =
+      options.find(ARG_FROM);
+  if (itr != options.end()) {
+    null_from_ = false;
+    from_ = itr->second;
+  }
+
+  itr = options.find(ARG_TO);
+  if (itr != options.end()) {
+    null_to_ = false;
+    to_ = itr->second;
+  }
+
+  if (is_key_hex_) {
+    if (!null_from_) {
+      from_ = HexToString(from_);
+    }
+    if (!null_to_) {
+      to_ = HexToString(to_);
+    }
+  }
+}
+
+void CompactorCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(CompactorCommand::Name());
+  ret.append(HelpRangeCmdArgs());
+  ret.append("\n");
+}
+
+void CompactorCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+
+  Slice* begin = nullptr;
+  Slice* end = nullptr;
+  if (!null_from_) {
+    begin = new Slice(from_);
+  }
+  if (!null_to_) {
+    end = new Slice(to_);
+  }
+
+  CompactRangeOptions cro;
+  cro.bottommost_level_compaction = BottommostLevelCompaction::kForce;
+
+  db_->CompactRange(cro, GetCfHandle(), begin, end);
+  exec_state_ = LDBCommandExecuteResult::Succeed("");
+
+  delete begin;
+  delete end;
+}
+
+// ----------------------------------------------------------------------------
+
+const std::string DBLoaderCommand::ARG_DISABLE_WAL = "disable_wal";
+const std::string DBLoaderCommand::ARG_BULK_LOAD = "bulk_load";
+const std::string DBLoaderCommand::ARG_COMPACT = "compact";
+
+DBLoaderCommand::DBLoaderCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(
+          options, flags, false,
+          BuildCmdLineOptions({ARG_HEX, ARG_KEY_HEX, ARG_VALUE_HEX, ARG_FROM,
+                               ARG_TO, ARG_CREATE_IF_MISSING, ARG_DISABLE_WAL,
+                               ARG_BULK_LOAD, ARG_COMPACT})),
+      disable_wal_(false),
+      bulk_load_(false),
+      compact_(false) {
+  create_if_missing_ = IsFlagPresent(flags, ARG_CREATE_IF_MISSING);
+  disable_wal_ = IsFlagPresent(flags, ARG_DISABLE_WAL);
+  bulk_load_ = IsFlagPresent(flags, ARG_BULK_LOAD);
+  compact_ = IsFlagPresent(flags, ARG_COMPACT);
+}
+
+void DBLoaderCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(DBLoaderCommand::Name());
+  ret.append(" [--" + ARG_CREATE_IF_MISSING + "]");
+  ret.append(" [--" + ARG_DISABLE_WAL + "]");
+  ret.append(" [--" + ARG_BULK_LOAD + "]");
+  ret.append(" [--" + ARG_COMPACT + "]");
+  ret.append("\n");
+}
+
+Options DBLoaderCommand::PrepareOptionsForOpenDB() {
+  Options opt = LDBCommand::PrepareOptionsForOpenDB();
+  opt.create_if_missing = create_if_missing_;
+  if (bulk_load_) {
+    opt.PrepareForBulkLoad();
+  }
+  return opt;
+}
+
+void DBLoaderCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+
+  WriteOptions write_options;
+  if (disable_wal_) {
+    write_options.disableWAL = true;
+  }
+
+  int bad_lines = 0;
+  std::string line;
+  // prefer ifstream getline performance vs that from std::cin istream
+  std::ifstream ifs_stdin("/dev/stdin");
+  std::istream* istream_p = ifs_stdin.is_open() ? &ifs_stdin : &std::cin;
+  while (getline(*istream_p, line, '\n')) {
+    std::string key;
+    std::string value;
+    if (ParseKeyValue(line, &key, &value, is_key_hex_, is_value_hex_)) {
+      db_->Put(write_options, GetCfHandle(), Slice(key), Slice(value));
+    } else if (0 == line.find("Keys in range:")) {
+      // ignore this line
+    } else if (0 == line.find("Created bg thread 0x")) {
+      // ignore this line
+    } else {
+      bad_lines ++;
+    }
+  }
+
+  if (bad_lines > 0) {
+    std::cout << "Warning: " << bad_lines << " bad lines ignored." << std::endl;
+  }
+  if (compact_) {
+    db_->CompactRange(CompactRangeOptions(), GetCfHandle(), nullptr, nullptr);
+  }
+}
+
+// ----------------------------------------------------------------------------
+
+namespace {
+
+void DumpManifestFile(Options options, std::string file, bool verbose, bool hex,
+                      bool json) {
+  EnvOptions sopt;
+  std::string dbname("dummy");
+  std::shared_ptr<Cache> tc(NewLRUCache(options.max_open_files - 10,
+                                        options.table_cache_numshardbits));
+  // Notice we are using the default options not through SanitizeOptions(),
+  // if VersionSet::DumpManifest() depends on any option done by
+  // SanitizeOptions(), we need to initialize it manually.
+  options.db_paths.emplace_back("dummy", 0);
+  options.num_levels = 64;
+  WriteController wc(options.delayed_write_rate);
+  WriteBufferManager wb(options.db_write_buffer_size);
+  ImmutableDBOptions immutable_db_options(options);
+  VersionSet versions(dbname, &immutable_db_options, sopt, tc.get(), &wb, &wc);
+  Status s = versions.DumpManifest(options, file, verbose, hex, json);
+  if (!s.ok()) {
+    printf("Error in processing file %s %s\n", file.c_str(),
+           s.ToString().c_str());
+  }
+}
+
+}  // namespace
+
+const std::string ManifestDumpCommand::ARG_VERBOSE = "verbose";
+const std::string ManifestDumpCommand::ARG_JSON = "json";
+const std::string ManifestDumpCommand::ARG_PATH = "path";
+
+void ManifestDumpCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(ManifestDumpCommand::Name());
+  ret.append(" [--" + ARG_VERBOSE + "]");
+  ret.append(" [--" + ARG_JSON + "]");
+  ret.append(" [--" + ARG_PATH + "=<path_to_manifest_file>]");
+  ret.append("\n");
+}
+
+ManifestDumpCommand::ManifestDumpCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(
+          options, flags, false,
+          BuildCmdLineOptions({ARG_VERBOSE, ARG_PATH, ARG_HEX, ARG_JSON})),
+      verbose_(false),
+      json_(false),
+      path_("") {
+  verbose_ = IsFlagPresent(flags, ARG_VERBOSE);
+  json_ = IsFlagPresent(flags, ARG_JSON);
+
+  std::map<std::string, std::string>::const_iterator itr =
+      options.find(ARG_PATH);
+  if (itr != options.end()) {
+    path_ = itr->second;
+    if (path_.empty()) {
+      exec_state_ = LDBCommandExecuteResult::Failed("--path: missing pathname");
+    }
+  }
+}
+
+void ManifestDumpCommand::DoCommand() {
+
+  std::string manifestfile;
+
+  if (!path_.empty()) {
+    manifestfile = path_;
+  } else {
+    bool found = false;
+    // We need to find the manifest file by searching the directory
+    // containing the db for files of the form MANIFEST_[0-9]+
+
+    auto CloseDir = [](DIR* p) { closedir(p); };
+    std::unique_ptr<DIR, decltype(CloseDir)> d(opendir(db_path_.c_str()),
+                                               CloseDir);
+
+    if (d == nullptr) {
+      exec_state_ =
+          LDBCommandExecuteResult::Failed(db_path_ + " is not a directory");
+      return;
+    }
+    struct dirent* entry;
+    while ((entry = readdir(d.get())) != nullptr) {
+      unsigned int match;
+      uint64_t num;
+      if (sscanf(entry->d_name, "MANIFEST-%" PRIu64 "%n", &num, &match) &&
+          match == strlen(entry->d_name)) {
+        if (!found) {
+          manifestfile = db_path_ + "/" + std::string(entry->d_name);
+          found = true;
+        } else {
+          exec_state_ = LDBCommandExecuteResult::Failed(
+              "Multiple MANIFEST files found; use --path to select one");
+          return;
+        }
+      }
+    }
+  }
+
+  if (verbose_) {
+    printf("Processing Manifest file %s\n", manifestfile.c_str());
+  }
+
+  DumpManifestFile(options_, manifestfile, verbose_, is_key_hex_, json_);
+
+  if (verbose_) {
+    printf("Processing Manifest file %s done\n", manifestfile.c_str());
+  }
+}
+
+// ----------------------------------------------------------------------------
+
+void ListColumnFamiliesCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(ListColumnFamiliesCommand::Name());
+  ret.append(" full_path_to_db_directory ");
+  ret.append("\n");
+}
+
+ListColumnFamiliesCommand::ListColumnFamiliesCommand(
+    const std::vector<std::string>& params,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false, {}) {
+  if (params.size() != 1) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "dbname must be specified for the list_column_families command");
+  } else {
+    dbname_ = params[0];
+  }
+}
+
+void ListColumnFamiliesCommand::DoCommand() {
+  std::vector<std::string> column_families;
+  Status s = DB::ListColumnFamilies(DBOptions(), dbname_, &column_families);
+  if (!s.ok()) {
+    printf("Error in processing db %s %s\n", dbname_.c_str(),
+           s.ToString().c_str());
+  } else {
+    printf("Column families in %s: \n{", dbname_.c_str());
+    bool first = true;
+    for (auto cf : column_families) {
+      if (!first) {
+        printf(", ");
+      }
+      first = false;
+      printf("%s", cf.c_str());
+    }
+    printf("}\n");
+  }
+}
+
+void CreateColumnFamilyCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(CreateColumnFamilyCommand::Name());
+  ret.append(" --db=<db_path> <new_column_family_name>");
+  ret.append("\n");
+}
+
+CreateColumnFamilyCommand::CreateColumnFamilyCommand(
+    const std::vector<std::string>& params,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, true, {ARG_DB}) {
+  if (params.size() != 1) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "new column family name must be specified");
+  } else {
+    new_cf_name_ = params[0];
+  }
+}
+
+void CreateColumnFamilyCommand::DoCommand() {
+  ColumnFamilyHandle* new_cf_handle = nullptr;
+  Status st = db_->CreateColumnFamily(options_, new_cf_name_, &new_cf_handle);
+  if (st.ok()) {
+    fprintf(stdout, "OK\n");
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "Fail to create new column family: " + st.ToString());
+  }
+  delete new_cf_handle;
+  CloseDB();
+}
+
+// ----------------------------------------------------------------------------
+
+namespace {
+
+std::string ReadableTime(int unixtime) {
+  char time_buffer [80];
+  time_t rawtime = unixtime;
+  struct tm tInfo;
+  struct tm* timeinfo = localtime_r(&rawtime, &tInfo);
+  assert(timeinfo == &tInfo);
+  strftime(time_buffer, 80, "%c", timeinfo);
+  return std::string(time_buffer);
+}
+
+// This function only called when it's the sane case of >1 buckets in time-range
+// Also called only when timekv falls between ttl_start and ttl_end provided
+void IncBucketCounts(std::vector<uint64_t>& bucket_counts, int ttl_start,
+                     int time_range, int bucket_size, int timekv,
+                     int num_buckets) {
+#ifdef NDEBUG
+  (void)time_range;
+  (void)num_buckets;
+#endif
+  assert(time_range > 0 && timekv >= ttl_start && bucket_size > 0 &&
+    timekv < (ttl_start + time_range) && num_buckets > 1);
+  int bucket = (timekv - ttl_start) / bucket_size;
+  bucket_counts[bucket]++;
+}
+
+void PrintBucketCounts(const std::vector<uint64_t>& bucket_counts,
+                       int ttl_start, int ttl_end, int bucket_size,
+                       int num_buckets) {
+  int time_point = ttl_start;
+  for(int i = 0; i < num_buckets - 1; i++, time_point += bucket_size) {
+    fprintf(stdout, "Keys in range %s to %s : %lu\n",
+            ReadableTime(time_point).c_str(),
+            ReadableTime(time_point + bucket_size).c_str(),
+            (unsigned long)bucket_counts[i]);
+  }
+  fprintf(stdout, "Keys in range %s to %s : %lu\n",
+          ReadableTime(time_point).c_str(),
+          ReadableTime(ttl_end).c_str(),
+          (unsigned long)bucket_counts[num_buckets - 1]);
+}
+
+}  // namespace
+
+const std::string InternalDumpCommand::ARG_COUNT_ONLY = "count_only";
+const std::string InternalDumpCommand::ARG_COUNT_DELIM = "count_delim";
+const std::string InternalDumpCommand::ARG_STATS = "stats";
+const std::string InternalDumpCommand::ARG_INPUT_KEY_HEX = "input_key_hex";
+
+InternalDumpCommand::InternalDumpCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(
+          options, flags, true,
+          BuildCmdLineOptions({ARG_HEX, ARG_KEY_HEX, ARG_VALUE_HEX, ARG_FROM,
+                               ARG_TO, ARG_MAX_KEYS, ARG_COUNT_ONLY,
+                               ARG_COUNT_DELIM, ARG_STATS, ARG_INPUT_KEY_HEX})),
+      has_from_(false),
+      has_to_(false),
+      max_keys_(-1),
+      delim_("."),
+      count_only_(false),
+      count_delim_(false),
+      print_stats_(false),
+      is_input_key_hex_(false) {
+  has_from_ = ParseStringOption(options, ARG_FROM, &from_);
+  has_to_ = ParseStringOption(options, ARG_TO, &to_);
+
+  ParseIntOption(options, ARG_MAX_KEYS, max_keys_, exec_state_);
+  std::map<std::string, std::string>::const_iterator itr =
+      options.find(ARG_COUNT_DELIM);
+  if (itr != options.end()) {
+    delim_ = itr->second;
+    count_delim_ = true;
+   // fprintf(stdout,"delim = %c\n",delim_[0]);
+  } else {
+    count_delim_ = IsFlagPresent(flags, ARG_COUNT_DELIM);
+    delim_=".";
+  }
+
+  print_stats_ = IsFlagPresent(flags, ARG_STATS);
+  count_only_ = IsFlagPresent(flags, ARG_COUNT_ONLY);
+  is_input_key_hex_ = IsFlagPresent(flags, ARG_INPUT_KEY_HEX);
+
+  if (is_input_key_hex_) {
+    if (has_from_) {
+      from_ = HexToString(from_);
+    }
+    if (has_to_) {
+      to_ = HexToString(to_);
+    }
+  }
+}
+
+void InternalDumpCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(InternalDumpCommand::Name());
+  ret.append(HelpRangeCmdArgs());
+  ret.append(" [--" + ARG_INPUT_KEY_HEX + "]");
+  ret.append(" [--" + ARG_MAX_KEYS + "=<N>]");
+  ret.append(" [--" + ARG_COUNT_ONLY + "]");
+  ret.append(" [--" + ARG_COUNT_DELIM + "=<char>]");
+  ret.append(" [--" + ARG_STATS + "]");
+  ret.append("\n");
+}
+
+void InternalDumpCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+
+  if (print_stats_) {
+    std::string stats;
+    if (db_->GetProperty(GetCfHandle(), "rocksdb.stats", &stats)) {
+      fprintf(stdout, "%s\n", stats.c_str());
+    }
+  }
+
+  // Cast as DBImpl to get internal iterator
+  std::vector<KeyVersion> key_versions;
+  Status st = GetAllKeyVersions(db_, from_, to_, max_keys_, &key_versions);
+  if (!st.ok()) {
+    exec_state_ = LDBCommandExecuteResult::Failed(st.ToString());
+    return;
+  }
+  std::string rtype1, rtype2, row, val;
+  rtype2 = "";
+  uint64_t c=0;
+  uint64_t s1=0,s2=0;
+
+  long long count = 0;
+  for (auto& key_version : key_versions) {
+    InternalKey ikey(key_version.user_key, key_version.sequence,
+                     static_cast<ValueType>(key_version.type));
+    if (has_to_ && ikey.user_key() == to_) {
+      // GetAllKeyVersions() includes keys with user key `to_`, but idump has
+      // traditionally excluded such keys.
+      break;
+    }
+    ++count;
+    int k;
+    if (count_delim_) {
+      rtype1 = "";
+      s1=0;
+      row = ikey.Encode().ToString();
+      val = key_version.value;
+      for(k=0;row[k]!='\x01' && row[k]!='\0';k++)
+        s1++;
+      for(k=0;val[k]!='\x01' && val[k]!='\0';k++)
+        s1++;
+      for(int j=0;row[j]!=delim_[0] && row[j]!='\0' && row[j]!='\x01';j++)
+        rtype1+=row[j];
+      if(rtype2.compare("") && rtype2.compare(rtype1)!=0) {
+        fprintf(stdout, "%s => count:%" PRIu64 "\tsize:%" PRIu64 "\n",
+                rtype2.c_str(), c, s2);
+        c=1;
+        s2=s1;
+        rtype2 = rtype1;
+      } else {
+        c++;
+        s2+=s1;
+        rtype2=rtype1;
+      }
+    }
+
+    if (!count_only_ && !count_delim_) {
+      std::string key = ikey.DebugString(is_key_hex_);
+      std::string value = Slice(key_version.value).ToString(is_value_hex_);
+      std::cout << key << " => " << value << "\n";
+    }
+
+    // Terminate if maximum number of keys have been dumped
+    if (max_keys_ > 0 && count >= max_keys_) break;
+  }
+  if(count_delim_) {
+    fprintf(stdout, "%s => count:%" PRIu64 "\tsize:%" PRIu64 "\n",
+            rtype2.c_str(), c, s2);
+  } else {
+    fprintf(stdout, "Internal keys in range: %lld\n", count);
+  }
+}
+
+const std::string DBDumperCommand::ARG_COUNT_ONLY = "count_only";
+const std::string DBDumperCommand::ARG_COUNT_DELIM = "count_delim";
+const std::string DBDumperCommand::ARG_STATS = "stats";
+const std::string DBDumperCommand::ARG_TTL_BUCKET = "bucket";
+
+DBDumperCommand::DBDumperCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, true,
+                 BuildCmdLineOptions(
+                     {ARG_TTL, ARG_HEX, ARG_KEY_HEX, ARG_VALUE_HEX, ARG_FROM,
+                      ARG_TO, ARG_MAX_KEYS, ARG_COUNT_ONLY, ARG_COUNT_DELIM,
+                      ARG_STATS, ARG_TTL_START, ARG_TTL_END, ARG_TTL_BUCKET,
+                      ARG_TIMESTAMP, ARG_PATH})),
+      null_from_(true),
+      null_to_(true),
+      max_keys_(-1),
+      count_only_(false),
+      count_delim_(false),
+      print_stats_(false) {
+  std::map<std::string, std::string>::const_iterator itr =
+      options.find(ARG_FROM);
+  if (itr != options.end()) {
+    null_from_ = false;
+    from_ = itr->second;
+  }
+
+  itr = options.find(ARG_TO);
+  if (itr != options.end()) {
+    null_to_ = false;
+    to_ = itr->second;
+  }
+
+  itr = options.find(ARG_MAX_KEYS);
+  if (itr != options.end()) {
+    try {
+#if defined(CYGWIN)
+      max_keys_ = strtol(itr->second.c_str(), 0, 10);
+#else
+      max_keys_ = std::stoi(itr->second);
+#endif
+    } catch (const std::invalid_argument&) {
+      exec_state_ = LDBCommandExecuteResult::Failed(ARG_MAX_KEYS +
+                                                    " has an invalid value");
+    } catch (const std::out_of_range&) {
+      exec_state_ = LDBCommandExecuteResult::Failed(
+          ARG_MAX_KEYS + " has a value out-of-range");
+    }
+  }
+  itr = options.find(ARG_COUNT_DELIM);
+  if (itr != options.end()) {
+    delim_ = itr->second;
+    count_delim_ = true;
+  } else {
+    count_delim_ = IsFlagPresent(flags, ARG_COUNT_DELIM);
+    delim_=".";
+  }
+
+  print_stats_ = IsFlagPresent(flags, ARG_STATS);
+  count_only_ = IsFlagPresent(flags, ARG_COUNT_ONLY);
+
+  if (is_key_hex_) {
+    if (!null_from_) {
+      from_ = HexToString(from_);
+    }
+    if (!null_to_) {
+      to_ = HexToString(to_);
+    }
+  }
+
+  itr = options.find(ARG_PATH);
+  if (itr != options.end()) {
+    path_ = itr->second;
+    if (db_path_.empty()) {
+      db_path_ = path_;
+    }
+  }
+}
+
+void DBDumperCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(DBDumperCommand::Name());
+  ret.append(HelpRangeCmdArgs());
+  ret.append(" [--" + ARG_TTL + "]");
+  ret.append(" [--" + ARG_MAX_KEYS + "=<N>]");
+  ret.append(" [--" + ARG_TIMESTAMP + "]");
+  ret.append(" [--" + ARG_COUNT_ONLY + "]");
+  ret.append(" [--" + ARG_COUNT_DELIM + "=<char>]");
+  ret.append(" [--" + ARG_STATS + "]");
+  ret.append(" [--" + ARG_TTL_BUCKET + "=<N>]");
+  ret.append(" [--" + ARG_TTL_START + "=<N>:- is inclusive]");
+  ret.append(" [--" + ARG_TTL_END + "=<N>:- is exclusive]");
+  ret.append(" [--" + ARG_PATH + "=<path_to_a_file>]");
+  ret.append("\n");
+}
+
+/**
+ * Handles two separate cases:
+ *
+ * 1) --db is specified - just dump the database.
+ *
+ * 2) --path is specified - determine based on file extension what dumping
+ *    function to call. Please note that we intentionally use the extension
+ *    and avoid probing the file contents under the assumption that renaming
+ *    the files is not a supported scenario.
+ *
+ */
+void DBDumperCommand::DoCommand() {
+  if (!db_) {
+    assert(!path_.empty());
+    std::string fileName = GetFileNameFromPath(path_);
+    uint64_t number;
+    FileType type;
+
+    exec_state_ = LDBCommandExecuteResult::Succeed("");
+
+    if (!ParseFileName(fileName, &number, &type)) {
+      exec_state_ =
+          LDBCommandExecuteResult::Failed("Can't parse file type: " + path_);
+      return;
+    }
+
+    switch (type) {
+      case kLogFile:
+        // TODO(myabandeh): allow configuring is_write_commited
+        DumpWalFile(options_, path_, /* print_header_ */ true,
+                    /* print_values_ */ true, true /* is_write_commited */,
+                    &exec_state_);
+        break;
+      case kTableFile:
+        DumpSstFile(options_, path_, is_key_hex_, /* show_properties */ true);
+        break;
+      case kDescriptorFile:
+        DumpManifestFile(options_, path_, /* verbose_ */ false, is_key_hex_,
+                         /*  json_ */ false);
+        break;
+      default:
+        exec_state_ = LDBCommandExecuteResult::Failed(
+            "File type not supported: " + path_);
+        break;
+    }
+
+  } else {
+    DoDumpCommand();
+  }
+}
+
+void DBDumperCommand::DoDumpCommand() {
+  assert(nullptr != db_);
+  assert(path_.empty());
+
+  // Parse command line args
+  uint64_t count = 0;
+  if (print_stats_) {
+    std::string stats;
+    if (db_->GetProperty("rocksdb.stats", &stats)) {
+      fprintf(stdout, "%s\n", stats.c_str());
+    }
+  }
+
+  // Setup key iterator
+  ReadOptions scan_read_opts;
+  scan_read_opts.total_order_seek = true;
+  Iterator* iter = db_->NewIterator(scan_read_opts, GetCfHandle());
+  Status st = iter->status();
+  if (!st.ok()) {
+    exec_state_ =
+        LDBCommandExecuteResult::Failed("Iterator error." + st.ToString());
+  }
+
+  if (!null_from_) {
+    iter->Seek(from_);
+  } else {
+    iter->SeekToFirst();
+  }
+
+  int max_keys = max_keys_;
+  int ttl_start;
+  if (!ParseIntOption(option_map_, ARG_TTL_START, ttl_start, exec_state_)) {
+    ttl_start = DBWithTTLImpl::kMinTimestamp;  // TTL introduction time
+  }
+  int ttl_end;
+  if (!ParseIntOption(option_map_, ARG_TTL_END, ttl_end, exec_state_)) {
+    ttl_end = DBWithTTLImpl::kMaxTimestamp;  // Max time allowed by TTL feature
+  }
+  if (ttl_end < ttl_start) {
+    fprintf(stderr, "Error: End time can't be less than start time\n");
+    delete iter;
+    return;
+  }
+  int time_range = ttl_end - ttl_start;
+  int bucket_size;
+  if (!ParseIntOption(option_map_, ARG_TTL_BUCKET, bucket_size, exec_state_) ||
+      bucket_size <= 0) {
+    bucket_size = time_range; // Will have just 1 bucket by default
+  }
+  //cretaing variables for row count of each type
+  std::string rtype1, rtype2, row, val;
+  rtype2 = "";
+  uint64_t c=0;
+  uint64_t s1=0,s2=0;
+
+  // At this point, bucket_size=0 => time_range=0
+  int num_buckets = (bucket_size >= time_range)
+                        ? 1
+                        : ((time_range + bucket_size - 1) / bucket_size);
+  std::vector<uint64_t> bucket_counts(num_buckets, 0);
+  if (is_db_ttl_ && !count_only_ && timestamp_ && !count_delim_) {
+    fprintf(stdout, "Dumping key-values from %s to %s\n",
+            ReadableTime(ttl_start).c_str(), ReadableTime(ttl_end).c_str());
+  }
+
+  HistogramImpl vsize_hist;
+
+  for (; iter->Valid(); iter->Next()) {
+    int rawtime = 0;
+    // If end marker was specified, we stop before it
+    if (!null_to_ && (iter->key().ToString() >= to_))
+      break;
+    // Terminate if maximum number of keys have been dumped
+    if (max_keys == 0)
+      break;
+    if (is_db_ttl_) {
+      TtlIterator* it_ttl = static_cast_with_check<TtlIterator, Iterator>(iter);
+      rawtime = it_ttl->timestamp();
+      if (rawtime < ttl_start || rawtime >= ttl_end) {
+        continue;
+      }
+    }
+    if (max_keys > 0) {
+      --max_keys;
+    }
+    if (is_db_ttl_ && num_buckets > 1) {
+      IncBucketCounts(bucket_counts, ttl_start, time_range, bucket_size,
+                      rawtime, num_buckets);
+    }
+    ++count;
+    if (count_delim_) {
+      rtype1 = "";
+      row = iter->key().ToString();
+      val = iter->value().ToString();
+      s1 = row.size()+val.size();
+      for(int j=0;row[j]!=delim_[0] && row[j]!='\0';j++)
+        rtype1+=row[j];
+      if(rtype2.compare("") && rtype2.compare(rtype1)!=0) {
+        fprintf(stdout, "%s => count:%" PRIu64 "\tsize:%" PRIu64 "\n",
+                rtype2.c_str(), c, s2);
+        c=1;
+        s2=s1;
+        rtype2 = rtype1;
+      } else {
+          c++;
+          s2+=s1;
+          rtype2=rtype1;
+      }
+
+    }
+
+    if (count_only_) {
+      vsize_hist.Add(iter->value().size());
+    }
+
+    if (!count_only_ && !count_delim_) {
+      if (is_db_ttl_ && timestamp_) {
+        fprintf(stdout, "%s ", ReadableTime(rawtime).c_str());
+      }
+      std::string str =
+          PrintKeyValue(iter->key().ToString(), iter->value().ToString(),
+                        is_key_hex_, is_value_hex_);
+      fprintf(stdout, "%s\n", str.c_str());
+    }
+  }
+
+  if (num_buckets > 1 && is_db_ttl_) {
+    PrintBucketCounts(bucket_counts, ttl_start, ttl_end, bucket_size,
+                      num_buckets);
+  } else if(count_delim_) {
+    fprintf(stdout, "%s => count:%" PRIu64 "\tsize:%" PRIu64 "\n",
+            rtype2.c_str(), c, s2);
+  } else {
+    fprintf(stdout, "Keys in range: %" PRIu64 "\n", count);
+  }
+
+  if (count_only_) {
+    fprintf(stdout, "Value size distribution: \n");
+    fprintf(stdout, "%s\n", vsize_hist.ToString().c_str());
+  }
+  // Clean up
+  delete iter;
+}
+
+const std::string ReduceDBLevelsCommand::ARG_NEW_LEVELS = "new_levels";
+const std::string ReduceDBLevelsCommand::ARG_PRINT_OLD_LEVELS =
+    "print_old_levels";
+
+ReduceDBLevelsCommand::ReduceDBLevelsCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false,
+                 BuildCmdLineOptions({ARG_NEW_LEVELS, ARG_PRINT_OLD_LEVELS})),
+      old_levels_(1 << 7),
+      new_levels_(-1),
+      print_old_levels_(false) {
+  ParseIntOption(option_map_, ARG_NEW_LEVELS, new_levels_, exec_state_);
+  print_old_levels_ = IsFlagPresent(flags, ARG_PRINT_OLD_LEVELS);
+
+  if(new_levels_ <= 0) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        " Use --" + ARG_NEW_LEVELS + " to specify a new level number\n");
+  }
+}
+
+std::vector<std::string> ReduceDBLevelsCommand::PrepareArgs(
+    const std::string& db_path, int new_levels, bool print_old_level) {
+  std::vector<std::string> ret;
+  ret.push_back("reduce_levels");
+  ret.push_back("--" + ARG_DB + "=" + db_path);
+  ret.push_back("--" + ARG_NEW_LEVELS + "=" + rocksdb::ToString(new_levels));
+  if(print_old_level) {
+    ret.push_back("--" + ARG_PRINT_OLD_LEVELS);
+  }
+  return ret;
+}
+
+void ReduceDBLevelsCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(ReduceDBLevelsCommand::Name());
+  ret.append(" --" + ARG_NEW_LEVELS + "=<New number of levels>");
+  ret.append(" [--" + ARG_PRINT_OLD_LEVELS + "]");
+  ret.append("\n");
+}
+
+Options ReduceDBLevelsCommand::PrepareOptionsForOpenDB() {
+  Options opt = LDBCommand::PrepareOptionsForOpenDB();
+  opt.num_levels = old_levels_;
+  opt.max_bytes_for_level_multiplier_additional.resize(opt.num_levels, 1);
+  // Disable size compaction
+  opt.max_bytes_for_level_base = 1ULL << 50;
+  opt.max_bytes_for_level_multiplier = 1;
+  return opt;
+}
+
+Status ReduceDBLevelsCommand::GetOldNumOfLevels(Options& opt,
+    int* levels) {
+  ImmutableDBOptions db_options(opt);
+  EnvOptions soptions;
+  std::shared_ptr<Cache> tc(
+      NewLRUCache(opt.max_open_files - 10, opt.table_cache_numshardbits));
+  const InternalKeyComparator cmp(opt.comparator);
+  WriteController wc(opt.delayed_write_rate);
+  WriteBufferManager wb(opt.db_write_buffer_size);
+  VersionSet versions(db_path_, &db_options, soptions, tc.get(), &wb, &wc);
+  std::vector<ColumnFamilyDescriptor> dummy;
+  ColumnFamilyDescriptor dummy_descriptor(kDefaultColumnFamilyName,
+                                          ColumnFamilyOptions(opt));
+  dummy.push_back(dummy_descriptor);
+  // We rely the VersionSet::Recover to tell us the internal data structures
+  // in the db. And the Recover() should never do any change
+  // (like LogAndApply) to the manifest file.
+  Status st = versions.Recover(dummy);
+  if (!st.ok()) {
+    return st;
+  }
+  int max = -1;
+  auto default_cfd = versions.GetColumnFamilySet()->GetDefault();
+  for (int i = 0; i < default_cfd->NumberLevels(); i++) {
+    if (default_cfd->current()->storage_info()->NumLevelFiles(i)) {
+      max = i;
+    }
+  }
+
+  *levels = max + 1;
+  return st;
+}
+
+void ReduceDBLevelsCommand::DoCommand() {
+  if (new_levels_ <= 1) {
+    exec_state_ =
+        LDBCommandExecuteResult::Failed("Invalid number of levels.\n");
+    return;
+  }
+
+  Status st;
+  Options opt = PrepareOptionsForOpenDB();
+  int old_level_num = -1;
+  st = GetOldNumOfLevels(opt, &old_level_num);
+  if (!st.ok()) {
+    exec_state_ = LDBCommandExecuteResult::Failed(st.ToString());
+    return;
+  }
+
+  if (print_old_levels_) {
+    fprintf(stdout, "The old number of levels in use is %d\n", old_level_num);
+  }
+
+  if (old_level_num <= new_levels_) {
+    return;
+  }
+
+  old_levels_ = old_level_num;
+
+  OpenDB();
+  if (exec_state_.IsFailed()) {
+    return;
+  }
+  assert(db_ != nullptr);
+  // Compact the whole DB to put all files to the highest level.
+  fprintf(stdout, "Compacting the db...\n");
+  db_->CompactRange(CompactRangeOptions(), GetCfHandle(), nullptr, nullptr);
+  CloseDB();
+
+  EnvOptions soptions;
+  st = VersionSet::ReduceNumberOfLevels(db_path_, &opt, soptions, new_levels_);
+  if (!st.ok()) {
+    exec_state_ = LDBCommandExecuteResult::Failed(st.ToString());
+    return;
+  }
+}
+
+const std::string ChangeCompactionStyleCommand::ARG_OLD_COMPACTION_STYLE =
+    "old_compaction_style";
+const std::string ChangeCompactionStyleCommand::ARG_NEW_COMPACTION_STYLE =
+    "new_compaction_style";
+
+ChangeCompactionStyleCommand::ChangeCompactionStyleCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false,
+                 BuildCmdLineOptions(
+                     {ARG_OLD_COMPACTION_STYLE, ARG_NEW_COMPACTION_STYLE})),
+      old_compaction_style_(-1),
+      new_compaction_style_(-1) {
+  ParseIntOption(option_map_, ARG_OLD_COMPACTION_STYLE, old_compaction_style_,
+    exec_state_);
+  if (old_compaction_style_ != kCompactionStyleLevel &&
+     old_compaction_style_ != kCompactionStyleUniversal) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "Use --" + ARG_OLD_COMPACTION_STYLE + " to specify old compaction " +
+        "style. Check ldb help for proper compaction style value.\n");
+    return;
+  }
+
+  ParseIntOption(option_map_, ARG_NEW_COMPACTION_STYLE, new_compaction_style_,
+    exec_state_);
+  if (new_compaction_style_ != kCompactionStyleLevel &&
+     new_compaction_style_ != kCompactionStyleUniversal) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "Use --" + ARG_NEW_COMPACTION_STYLE + " to specify new compaction " +
+        "style. Check ldb help for proper compaction style value.\n");
+    return;
+  }
+
+  if (new_compaction_style_ == old_compaction_style_) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "Old compaction style is the same as new compaction style. "
+        "Nothing to do.\n");
+    return;
+  }
+
+  if (old_compaction_style_ == kCompactionStyleUniversal &&
+      new_compaction_style_ == kCompactionStyleLevel) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "Convert from universal compaction to level compaction. "
+        "Nothing to do.\n");
+    return;
+  }
+}
+
+void ChangeCompactionStyleCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(ChangeCompactionStyleCommand::Name());
+  ret.append(" --" + ARG_OLD_COMPACTION_STYLE + "=<Old compaction style: 0 " +
+             "for level compaction, 1 for universal compaction>");
+  ret.append(" --" + ARG_NEW_COMPACTION_STYLE + "=<New compaction style: 0 " +
+             "for level compaction, 1 for universal compaction>");
+  ret.append("\n");
+}
+
+Options ChangeCompactionStyleCommand::PrepareOptionsForOpenDB() {
+  Options opt = LDBCommand::PrepareOptionsForOpenDB();
+
+  if (old_compaction_style_ == kCompactionStyleLevel &&
+      new_compaction_style_ == kCompactionStyleUniversal) {
+    // In order to convert from level compaction to universal compaction, we
+    // need to compact all data into a single file and move it to level 0.
+    opt.disable_auto_compactions = true;
+    opt.target_file_size_base = INT_MAX;
+    opt.target_file_size_multiplier = 1;
+    opt.max_bytes_for_level_base = INT_MAX;
+    opt.max_bytes_for_level_multiplier = 1;
+  }
+
+  return opt;
+}
+
+void ChangeCompactionStyleCommand::DoCommand() {
+  // print db stats before we have made any change
+  std::string property;
+  std::string files_per_level;
+  for (int i = 0; i < db_->NumberLevels(GetCfHandle()); i++) {
+    db_->GetProperty(GetCfHandle(),
+                     "rocksdb.num-files-at-level" + NumberToString(i),
+                     &property);
+
+    // format print string
+    char buf[100];
+    snprintf(buf, sizeof(buf), "%s%s", (i ? "," : ""), property.c_str());
+    files_per_level += buf;
+  }
+  fprintf(stdout, "files per level before compaction: %s\n",
+          files_per_level.c_str());
+
+  // manual compact into a single file and move the file to level 0
+  CompactRangeOptions compact_options;
+  compact_options.change_level = true;
+  compact_options.target_level = 0;
+  db_->CompactRange(compact_options, GetCfHandle(), nullptr, nullptr);
+
+  // verify compaction result
+  files_per_level = "";
+  int num_files = 0;
+  for (int i = 0; i < db_->NumberLevels(GetCfHandle()); i++) {
+    db_->GetProperty(GetCfHandle(),
+                     "rocksdb.num-files-at-level" + NumberToString(i),
+                     &property);
+
+    // format print string
+    char buf[100];
+    snprintf(buf, sizeof(buf), "%s%s", (i ? "," : ""), property.c_str());
+    files_per_level += buf;
+
+    num_files = atoi(property.c_str());
+
+    // level 0 should have only 1 file
+    if (i == 0 && num_files != 1) {
+      exec_state_ = LDBCommandExecuteResult::Failed(
+          "Number of db files at "
+          "level 0 after compaction is " +
+          ToString(num_files) + ", not 1.\n");
+      return;
+    }
+    // other levels should have no file
+    if (i > 0 && num_files != 0) {
+      exec_state_ = LDBCommandExecuteResult::Failed(
+          "Number of db files at "
+          "level " +
+          ToString(i) + " after compaction is " + ToString(num_files) +
+          ", not 0.\n");
+      return;
+    }
+  }
+
+  fprintf(stdout, "files per level after compaction: %s\n",
+          files_per_level.c_str());
+}
+
+// ----------------------------------------------------------------------------
+
+namespace {
+
+struct StdErrReporter : public log::Reader::Reporter {
+  void Corruption(size_t /*bytes*/, const Status& s) override {
+    std::cerr << "Corruption detected in log file " << s.ToString() << "\n";
+  }
+};
+
+class InMemoryHandler : public WriteBatch::Handler {
+ public:
+  InMemoryHandler(std::stringstream& row, bool print_values,
+                  bool write_after_commit = false)
+      : Handler(),
+        row_(row),
+        print_values_(print_values),
+        write_after_commit_(write_after_commit) {}
+
+  void commonPutMerge(const Slice& key, const Slice& value) {
+    std::string k = LDBCommand::StringToHex(key.ToString());
+    if (print_values_) {
+      std::string v = LDBCommand::StringToHex(value.ToString());
+      row_ << k << " : ";
+      row_ << v << " ";
+    } else {
+      row_ << k << " ";
+    }
+  }
+
+  Status PutCF(uint32_t cf, const Slice& key, const Slice& value) override {
+    row_ << "PUT(" << cf << ") : ";
+    commonPutMerge(key, value);
+    return Status::OK();
+  }
+
+  Status MergeCF(uint32_t cf, const Slice& key, const Slice& value) override {
+    row_ << "MERGE(" << cf << ") : ";
+    commonPutMerge(key, value);
+    return Status::OK();
+  }
+
+  Status MarkNoop(bool) override {
+    row_ << "NOOP ";
+    return Status::OK();
+  }
+
+  Status DeleteCF(uint32_t cf, const Slice& key) override {
+    row_ << "DELETE(" << cf << ") : ";
+    row_ << LDBCommand::StringToHex(key.ToString()) << " ";
+    return Status::OK();
+  }
+
+  Status SingleDeleteCF(uint32_t cf, const Slice& key) override {
+    row_ << "SINGLE_DELETE(" << cf << ") : ";
+    row_ << LDBCommand::StringToHex(key.ToString()) << " ";
+    return Status::OK();
+  }
+
+  Status DeleteRangeCF(uint32_t cf, const Slice& begin_key,
+                       const Slice& end_key) override {
+    row_ << "DELETE_RANGE(" << cf << ") : ";
+    row_ << LDBCommand::StringToHex(begin_key.ToString()) << " ";
+    row_ << LDBCommand::StringToHex(end_key.ToString()) << " ";
+    return Status::OK();
+  }
+
+  Status MarkBeginPrepare(bool unprepare) override {
+    row_ << "BEGIN_PREPARE(";
+    row_ << (unprepare ? "true" : "false") << ") ";
+    return Status::OK();
+  }
+
+  Status MarkEndPrepare(const Slice& xid) override {
+    row_ << "END_PREPARE(";
+    row_ << LDBCommand::StringToHex(xid.ToString()) << ") ";
+    return Status::OK();
+  }
+
+  Status MarkRollback(const Slice& xid) override {
+    row_ << "ROLLBACK(";
+    row_ << LDBCommand::StringToHex(xid.ToString()) << ") ";
+    return Status::OK();
+  }
+
+  Status MarkCommit(const Slice& xid) override {
+    row_ << "COMMIT(";
+    row_ << LDBCommand::StringToHex(xid.ToString()) << ") ";
+    return Status::OK();
+  }
+
+  ~InMemoryHandler() override {}
+
+ protected:
+  bool WriteAfterCommit() const override { return write_after_commit_; }
+
+ private:
+  std::stringstream& row_;
+  bool print_values_;
+  bool write_after_commit_;
+};
+
+void DumpWalFile(Options options, std::string wal_file, bool print_header,
+                 bool print_values, bool is_write_committed,
+                 LDBCommandExecuteResult* exec_state) {
+  Env* env = options.env;
+  EnvOptions soptions(options);
+  std::unique_ptr<SequentialFileReader> wal_file_reader;
+
+  Status status;
+  {
+    std::unique_ptr<SequentialFile> file;
+    status = env->NewSequentialFile(wal_file, &file, soptions);
+    if (status.ok()) {
+      wal_file_reader.reset(
+          new SequentialFileReader(std::move(file), wal_file));
+    }
+  }
+  if (!status.ok()) {
+    if (exec_state) {
+      *exec_state = LDBCommandExecuteResult::Failed("Failed to open WAL file " +
+                                                    status.ToString());
+    } else {
+      std::cerr << "Error: Failed to open WAL file " << status.ToString()
+                << std::endl;
+    }
+  } else {
+    StdErrReporter reporter;
+    uint64_t log_number;
+    FileType type;
+
+    // we need the log number, but ParseFilename expects dbname/NNN.log.
+    std::string sanitized = wal_file;
+    size_t lastslash = sanitized.rfind('/');
+    if (lastslash != std::string::npos)
+      sanitized = sanitized.substr(lastslash + 1);
+    if (!ParseFileName(sanitized, &log_number, &type)) {
+      // bogus input, carry on as best we can
+      log_number = 0;
+    }
+    log::Reader reader(options.info_log, std::move(wal_file_reader), &reporter,
+                       true /* checksum */, log_number);
+    std::string scratch;
+    WriteBatch batch;
+    Slice record;
+    std::stringstream row;
+    if (print_header) {
+      std::cout << "Sequence,Count,ByteSize,Physical Offset,Key(s)";
+      if (print_values) {
+        std::cout << " : value ";
+      }
+      std::cout << "\n";
+    }
+    while (reader.ReadRecord(&record, &scratch)) {
+      row.str("");
+      if (record.size() < WriteBatchInternal::kHeader) {
+        reporter.Corruption(record.size(),
+                            Status::Corruption("log record too small"));
+      } else {
+        WriteBatchInternal::SetContents(&batch, record);
+        row << WriteBatchInternal::Sequence(&batch) << ",";
+        row << WriteBatchInternal::Count(&batch) << ",";
+        row << WriteBatchInternal::ByteSize(&batch) << ",";
+        row << reader.LastRecordOffset() << ",";
+        InMemoryHandler handler(row, print_values, is_write_committed);
+        batch.Iterate(&handler);
+        row << "\n";
+      }
+      std::cout << row.str();
+    }
+  }
+}
+
+}  // namespace
+
+const std::string WALDumperCommand::ARG_WAL_FILE = "walfile";
+const std::string WALDumperCommand::ARG_WRITE_COMMITTED = "write_committed";
+const std::string WALDumperCommand::ARG_PRINT_VALUE = "print_value";
+const std::string WALDumperCommand::ARG_PRINT_HEADER = "header";
+
+WALDumperCommand::WALDumperCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, true,
+                 BuildCmdLineOptions({ARG_WAL_FILE, ARG_WRITE_COMMITTED,
+                                      ARG_PRINT_HEADER, ARG_PRINT_VALUE})),
+      print_header_(false),
+      print_values_(false),
+      is_write_committed_(false) {
+  wal_file_.clear();
+
+  std::map<std::string, std::string>::const_iterator itr =
+      options.find(ARG_WAL_FILE);
+  if (itr != options.end()) {
+    wal_file_ = itr->second;
+  }
+
+
+  print_header_ = IsFlagPresent(flags, ARG_PRINT_HEADER);
+  print_values_ = IsFlagPresent(flags, ARG_PRINT_VALUE);
+  is_write_committed_ = ParseBooleanOption(options, ARG_WRITE_COMMITTED, true);
+
+  if (wal_file_.empty()) {
+    exec_state_ = LDBCommandExecuteResult::Failed("Argument " + ARG_WAL_FILE +
+                                                  " must be specified.");
+  }
+}
+
+void WALDumperCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(WALDumperCommand::Name());
+  ret.append(" --" + ARG_WAL_FILE + "=<write_ahead_log_file_path>");
+  ret.append(" [--" + ARG_PRINT_HEADER + "] ");
+  ret.append(" [--" + ARG_PRINT_VALUE + "] ");
+  ret.append(" [--" + ARG_WRITE_COMMITTED + "=true|false] ");
+  ret.append("\n");
+}
+
+void WALDumperCommand::DoCommand() {
+  DumpWalFile(options_, wal_file_, print_header_, print_values_,
+              is_write_committed_, &exec_state_);
+}
+
+// ----------------------------------------------------------------------------
+
+GetCommand::GetCommand(const std::vector<std::string>& params,
+                       const std::map<std::string, std::string>& options,
+                       const std::vector<std::string>& flags)
+    : LDBCommand(
+          options, flags, true,
+          BuildCmdLineOptions({ARG_TTL, ARG_HEX, ARG_KEY_HEX, ARG_VALUE_HEX})) {
+  if (params.size() != 1) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "<key> must be specified for the get command");
+  } else {
+    key_ = params.at(0);
+  }
+
+  if (is_key_hex_) {
+    key_ = HexToString(key_);
+  }
+}
+
+void GetCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(GetCommand::Name());
+  ret.append(" <key>");
+  ret.append(" [--" + ARG_TTL + "]");
+  ret.append("\n");
+}
+
+void GetCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+  std::string value;
+  Status st = db_->Get(ReadOptions(), GetCfHandle(), key_, &value);
+  if (st.ok()) {
+    fprintf(stdout, "%s\n",
+              (is_value_hex_ ? StringToHex(value) : value).c_str());
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(st.ToString());
+  }
+}
+
+// ----------------------------------------------------------------------------
+
+ApproxSizeCommand::ApproxSizeCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, true,
+                 BuildCmdLineOptions(
+                     {ARG_HEX, ARG_KEY_HEX, ARG_VALUE_HEX, ARG_FROM, ARG_TO})) {
+  if (options.find(ARG_FROM) != options.end()) {
+    start_key_ = options.find(ARG_FROM)->second;
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        ARG_FROM + " must be specified for approxsize command");
+    return;
+  }
+
+  if (options.find(ARG_TO) != options.end()) {
+    end_key_ = options.find(ARG_TO)->second;
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        ARG_TO + " must be specified for approxsize command");
+    return;
+  }
+
+  if (is_key_hex_) {
+    start_key_ = HexToString(start_key_);
+    end_key_ = HexToString(end_key_);
+  }
+}
+
+void ApproxSizeCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(ApproxSizeCommand::Name());
+  ret.append(HelpRangeCmdArgs());
+  ret.append("\n");
+}
+
+void ApproxSizeCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+  Range ranges[1];
+  ranges[0] = Range(start_key_, end_key_);
+  uint64_t sizes[1];
+  db_->GetApproximateSizes(GetCfHandle(), ranges, 1, sizes);
+  fprintf(stdout, "%lu\n", (unsigned long)sizes[0]);
+  /* Weird that GetApproximateSizes() returns void, although documentation
+   * says that it returns a Status object.
+  if (!st.ok()) {
+    exec_state_ = LDBCommandExecuteResult::Failed(st.ToString());
+  }
+  */
+}
+
+// ----------------------------------------------------------------------------
+
+BatchPutCommand::BatchPutCommand(
+    const std::vector<std::string>& params,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false,
+                 BuildCmdLineOptions({ARG_TTL, ARG_HEX, ARG_KEY_HEX,
+                                      ARG_VALUE_HEX, ARG_CREATE_IF_MISSING})) {
+  if (params.size() < 2) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "At least one <key> <value> pair must be specified batchput.");
+  } else if (params.size() % 2 != 0) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "Equal number of <key>s and <value>s must be specified for batchput.");
+  } else {
+    for (size_t i = 0; i < params.size(); i += 2) {
+      std::string key = params.at(i);
+      std::string value = params.at(i + 1);
+      key_values_.push_back(std::pair<std::string, std::string>(
+          is_key_hex_ ? HexToString(key) : key,
+          is_value_hex_ ? HexToString(value) : value));
+    }
+  }
+  create_if_missing_ = IsFlagPresent(flags_, ARG_CREATE_IF_MISSING);
+}
+
+void BatchPutCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(BatchPutCommand::Name());
+  ret.append(" <key> <value> [<key> <value>] [..]");
+  ret.append(" [--" + ARG_TTL + "]");
+  ret.append("\n");
+}
+
+void BatchPutCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+  WriteBatch batch;
+
+  for (std::vector<std::pair<std::string, std::string>>::const_iterator itr =
+           key_values_.begin();
+       itr != key_values_.end(); ++itr) {
+    batch.Put(GetCfHandle(), itr->first, itr->second);
+  }
+  Status st = db_->Write(WriteOptions(), &batch);
+  if (st.ok()) {
+    fprintf(stdout, "OK\n");
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(st.ToString());
+  }
+}
+
+Options BatchPutCommand::PrepareOptionsForOpenDB() {
+  Options opt = LDBCommand::PrepareOptionsForOpenDB();
+  opt.create_if_missing = create_if_missing_;
+  return opt;
+}
+
+// ----------------------------------------------------------------------------
+
+ScanCommand::ScanCommand(const std::vector<std::string>& /*params*/,
+                         const std::map<std::string, std::string>& options,
+                         const std::vector<std::string>& flags)
+    : LDBCommand(
+          options, flags, true,
+          BuildCmdLineOptions({ARG_TTL, ARG_NO_VALUE, ARG_HEX, ARG_KEY_HEX,
+                               ARG_TO, ARG_VALUE_HEX, ARG_FROM, ARG_TIMESTAMP,
+                               ARG_MAX_KEYS, ARG_TTL_START, ARG_TTL_END})),
+      start_key_specified_(false),
+      end_key_specified_(false),
+      max_keys_scanned_(-1),
+      no_value_(false) {
+  std::map<std::string, std::string>::const_iterator itr =
+      options.find(ARG_FROM);
+  if (itr != options.end()) {
+    start_key_ = itr->second;
+    if (is_key_hex_) {
+      start_key_ = HexToString(start_key_);
+    }
+    start_key_specified_ = true;
+  }
+  itr = options.find(ARG_TO);
+  if (itr != options.end()) {
+    end_key_ = itr->second;
+    if (is_key_hex_) {
+      end_key_ = HexToString(end_key_);
+    }
+    end_key_specified_ = true;
+  }
+
+  std::vector<std::string>::const_iterator vitr =
+      std::find(flags.begin(), flags.end(), ARG_NO_VALUE);
+  if (vitr != flags.end()) {
+    no_value_ = true;
+  }
+
+  itr = options.find(ARG_MAX_KEYS);
+  if (itr != options.end()) {
+    try {
+#if defined(CYGWIN)
+      max_keys_scanned_ = strtol(itr->second.c_str(), 0, 10);
+#else
+      max_keys_scanned_ = std::stoi(itr->second);
+#endif
+    } catch (const std::invalid_argument&) {
+      exec_state_ = LDBCommandExecuteResult::Failed(ARG_MAX_KEYS +
+                                                    " has an invalid value");
+    } catch (const std::out_of_range&) {
+      exec_state_ = LDBCommandExecuteResult::Failed(
+          ARG_MAX_KEYS + " has a value out-of-range");
+    }
+  }
+}
+
+void ScanCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(ScanCommand::Name());
+  ret.append(HelpRangeCmdArgs());
+  ret.append(" [--" + ARG_TTL + "]");
+  ret.append(" [--" + ARG_TIMESTAMP + "]");
+  ret.append(" [--" + ARG_MAX_KEYS + "=<N>q] ");
+  ret.append(" [--" + ARG_TTL_START + "=<N>:- is inclusive]");
+  ret.append(" [--" + ARG_TTL_END + "=<N>:- is exclusive]");
+  ret.append(" [--" + ARG_NO_VALUE + "]");
+  ret.append("\n");
+}
+
+void ScanCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+
+  int num_keys_scanned = 0;
+  ReadOptions scan_read_opts;
+  scan_read_opts.total_order_seek = true;
+  Iterator* it = db_->NewIterator(scan_read_opts, GetCfHandle());
+  if (start_key_specified_) {
+    it->Seek(start_key_);
+  } else {
+    it->SeekToFirst();
+  }
+  int ttl_start;
+  if (!ParseIntOption(option_map_, ARG_TTL_START, ttl_start, exec_state_)) {
+    ttl_start = DBWithTTLImpl::kMinTimestamp;  // TTL introduction time
+  }
+  int ttl_end;
+  if (!ParseIntOption(option_map_, ARG_TTL_END, ttl_end, exec_state_)) {
+    ttl_end = DBWithTTLImpl::kMaxTimestamp;  // Max time allowed by TTL feature
+  }
+  if (ttl_end < ttl_start) {
+    fprintf(stderr, "Error: End time can't be less than start time\n");
+    delete it;
+    return;
+  }
+  if (is_db_ttl_ && timestamp_) {
+    fprintf(stdout, "Scanning key-values from %s to %s\n",
+            ReadableTime(ttl_start).c_str(), ReadableTime(ttl_end).c_str());
+  }
+  for ( ;
+        it->Valid() && (!end_key_specified_ || it->key().ToString() < end_key_);
+        it->Next()) {
+    if (is_db_ttl_) {
+      TtlIterator* it_ttl = static_cast_with_check<TtlIterator, Iterator>(it);
+      int rawtime = it_ttl->timestamp();
+      if (rawtime < ttl_start || rawtime >= ttl_end) {
+        continue;
+      }
+      if (timestamp_) {
+        fprintf(stdout, "%s ", ReadableTime(rawtime).c_str());
+      }
+    }
+
+    Slice key_slice = it->key();
+
+    std::string formatted_key;
+    if (is_key_hex_) {
+      formatted_key = "0x" + key_slice.ToString(true /* hex */);
+      key_slice = formatted_key;
+    } else if (ldb_options_.key_formatter) {
+      formatted_key = ldb_options_.key_formatter->Format(key_slice);
+      key_slice = formatted_key;
+    }
+
+    if (no_value_) {
+      fprintf(stdout, "%.*s\n", static_cast<int>(key_slice.size()),
+              key_slice.data());
+    } else {
+      Slice val_slice = it->value();
+      std::string formatted_value;
+      if (is_value_hex_) {
+        formatted_value = "0x" + val_slice.ToString(true /* hex */);
+        val_slice = formatted_value;
+      }
+      fprintf(stdout, "%.*s : %.*s\n", static_cast<int>(key_slice.size()),
+              key_slice.data(), static_cast<int>(val_slice.size()),
+              val_slice.data());
+    }
+
+    num_keys_scanned++;
+    if (max_keys_scanned_ >= 0 && num_keys_scanned >= max_keys_scanned_) {
+      break;
+    }
+  }
+  if (!it->status().ok()) {  // Check for any errors found during the scan
+    exec_state_ = LDBCommandExecuteResult::Failed(it->status().ToString());
+  }
+  delete it;
+}
+
+// ----------------------------------------------------------------------------
+
+DeleteCommand::DeleteCommand(const std::vector<std::string>& params,
+                             const std::map<std::string, std::string>& options,
+                             const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false,
+                 BuildCmdLineOptions({ARG_HEX, ARG_KEY_HEX, ARG_VALUE_HEX})) {
+  if (params.size() != 1) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "KEY must be specified for the delete command");
+  } else {
+    key_ = params.at(0);
+    if (is_key_hex_) {
+      key_ = HexToString(key_);
+    }
+  }
+}
+
+void DeleteCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(DeleteCommand::Name() + " <key>");
+  ret.append("\n");
+}
+
+void DeleteCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+  Status st = db_->Delete(WriteOptions(), GetCfHandle(), key_);
+  if (st.ok()) {
+    fprintf(stdout, "OK\n");
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(st.ToString());
+  }
+}
+
+DeleteRangeCommand::DeleteRangeCommand(
+    const std::vector<std::string>& params,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false,
+                 BuildCmdLineOptions({ARG_HEX, ARG_KEY_HEX, ARG_VALUE_HEX})) {
+  if (params.size() != 2) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "begin and end keys must be specified for the delete command");
+  } else {
+    begin_key_ = params.at(0);
+    end_key_ = params.at(1);
+    if (is_key_hex_) {
+      begin_key_ = HexToString(begin_key_);
+      end_key_ = HexToString(end_key_);
+    }
+  }
+}
+
+void DeleteRangeCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(DeleteRangeCommand::Name() + " <begin key> <end key>");
+  ret.append("\n");
+}
+
+void DeleteRangeCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+  Status st =
+      db_->DeleteRange(WriteOptions(), GetCfHandle(), begin_key_, end_key_);
+  if (st.ok()) {
+    fprintf(stdout, "OK\n");
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(st.ToString());
+  }
+}
+
+PutCommand::PutCommand(const std::vector<std::string>& params,
+                       const std::map<std::string, std::string>& options,
+                       const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false,
+                 BuildCmdLineOptions({ARG_TTL, ARG_HEX, ARG_KEY_HEX,
+                                      ARG_VALUE_HEX, ARG_CREATE_IF_MISSING})) {
+  if (params.size() != 2) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "<key> and <value> must be specified for the put command");
+  } else {
+    key_ = params.at(0);
+    value_ = params.at(1);
+  }
+
+  if (is_key_hex_) {
+    key_ = HexToString(key_);
+  }
+
+  if (is_value_hex_) {
+    value_ = HexToString(value_);
+  }
+  create_if_missing_ = IsFlagPresent(flags_, ARG_CREATE_IF_MISSING);
+}
+
+void PutCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(PutCommand::Name());
+  ret.append(" <key> <value> ");
+  ret.append(" [--" + ARG_TTL + "]");
+  ret.append("\n");
+}
+
+void PutCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+  Status st = db_->Put(WriteOptions(), GetCfHandle(), key_, value_);
+  if (st.ok()) {
+    fprintf(stdout, "OK\n");
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(st.ToString());
+  }
+}
+
+Options PutCommand::PrepareOptionsForOpenDB() {
+  Options opt = LDBCommand::PrepareOptionsForOpenDB();
+  opt.create_if_missing = create_if_missing_;
+  return opt;
+}
+
+// ----------------------------------------------------------------------------
+
+const char* DBQuerierCommand::HELP_CMD = "help";
+const char* DBQuerierCommand::GET_CMD = "get";
+const char* DBQuerierCommand::PUT_CMD = "put";
+const char* DBQuerierCommand::DELETE_CMD = "delete";
+
+DBQuerierCommand::DBQuerierCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(
+          options, flags, false,
+          BuildCmdLineOptions({ARG_TTL, ARG_HEX, ARG_KEY_HEX, ARG_VALUE_HEX})) {
+
+}
+
+void DBQuerierCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(DBQuerierCommand::Name());
+  ret.append(" [--" + ARG_TTL + "]");
+  ret.append("\n");
+  ret.append("    Starts a REPL shell.  Type help for list of available "
+             "commands.");
+  ret.append("\n");
+}
+
+void DBQuerierCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+
+  ReadOptions read_options;
+  WriteOptions write_options;
+
+  std::string line;
+  std::string key;
+  std::string value;
+  while (getline(std::cin, line, '\n')) {
+    // Parse line into std::vector<std::string>
+    std::vector<std::string> tokens;
+    size_t pos = 0;
+    while (true) {
+      size_t pos2 = line.find(' ', pos);
+      if (pos2 == std::string::npos) {
+        break;
+      }
+      tokens.push_back(line.substr(pos, pos2-pos));
+      pos = pos2 + 1;
+    }
+    tokens.push_back(line.substr(pos));
+
+    const std::string& cmd = tokens[0];
+
+    if (cmd == HELP_CMD) {
+      fprintf(stdout,
+              "get <key>\n"
+              "put <key> <value>\n"
+              "delete <key>\n");
+    } else if (cmd == DELETE_CMD && tokens.size() == 2) {
+      key = (is_key_hex_ ? HexToString(tokens[1]) : tokens[1]);
+      db_->Delete(write_options, GetCfHandle(), Slice(key));
+      fprintf(stdout, "Successfully deleted %s\n", tokens[1].c_str());
+    } else if (cmd == PUT_CMD && tokens.size() == 3) {
+      key = (is_key_hex_ ? HexToString(tokens[1]) : tokens[1]);
+      value = (is_value_hex_ ? HexToString(tokens[2]) : tokens[2]);
+      db_->Put(write_options, GetCfHandle(), Slice(key), Slice(value));
+      fprintf(stdout, "Successfully put %s %s\n",
+              tokens[1].c_str(), tokens[2].c_str());
+    } else if (cmd == GET_CMD && tokens.size() == 2) {
+      key = (is_key_hex_ ? HexToString(tokens[1]) : tokens[1]);
+      if (db_->Get(read_options, GetCfHandle(), Slice(key), &value).ok()) {
+        fprintf(stdout, "%s\n", PrintKeyValue(key, value,
+              is_key_hex_, is_value_hex_).c_str());
+      } else {
+        fprintf(stdout, "Not found %s\n", tokens[1].c_str());
+      }
+    } else {
+      fprintf(stdout, "Unknown command %s\n", line.c_str());
+    }
+  }
+}
+
+// ----------------------------------------------------------------------------
+
+CheckConsistencyCommand::CheckConsistencyCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false, BuildCmdLineOptions({})) {}
+
+void CheckConsistencyCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(CheckConsistencyCommand::Name());
+  ret.append("\n");
+}
+
+void CheckConsistencyCommand::DoCommand() {
+  Options opt = PrepareOptionsForOpenDB();
+  opt.paranoid_checks = true;
+  if (!exec_state_.IsNotStarted()) {
+    return;
+  }
+  DB* db;
+  Status st = DB::OpenForReadOnly(opt, db_path_, &db, false);
+  delete db;
+  if (st.ok()) {
+    fprintf(stdout, "OK\n");
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(st.ToString());
+  }
+}
+
+// ----------------------------------------------------------------------------
+
+const std::string CheckPointCommand::ARG_CHECKPOINT_DIR = "checkpoint_dir";
+
+CheckPointCommand::CheckPointCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false /* is_read_only */,
+                 BuildCmdLineOptions({ARG_CHECKPOINT_DIR})) {
+  auto itr = options.find(ARG_CHECKPOINT_DIR);
+  if (itr != options.end()) {
+    checkpoint_dir_ = itr->second;
+  }
+}
+
+void CheckPointCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(CheckPointCommand::Name());
+  ret.append(" [--" + ARG_CHECKPOINT_DIR + "] ");
+  ret.append("\n");
+}
+
+void CheckPointCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+  Checkpoint* checkpoint;
+  Status status = Checkpoint::Create(db_, &checkpoint);
+  status = checkpoint->CreateCheckpoint(checkpoint_dir_);
+  if (status.ok()) {
+    printf("OK\n");
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(status.ToString());
+  }
+}
+
+// ----------------------------------------------------------------------------
+
+RepairCommand::RepairCommand(const std::vector<std::string>& /*params*/,
+                             const std::map<std::string, std::string>& options,
+                             const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false, BuildCmdLineOptions({})) {}
+
+void RepairCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(RepairCommand::Name());
+  ret.append("\n");
+}
+
+void RepairCommand::DoCommand() {
+  Options options = PrepareOptionsForOpenDB();
+  options.info_log.reset(new StderrLogger(InfoLogLevel::WARN_LEVEL));
+  Status status = RepairDB(db_path_, options);
+  if (status.ok()) {
+    printf("OK\n");
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(status.ToString());
+  }
+}
+
+// ----------------------------------------------------------------------------
+
+const std::string BackupableCommand::ARG_NUM_THREADS = "num_threads";
+const std::string BackupableCommand::ARG_BACKUP_ENV_URI = "backup_env_uri";
+const std::string BackupableCommand::ARG_BACKUP_DIR = "backup_dir";
+const std::string BackupableCommand::ARG_STDERR_LOG_LEVEL = "stderr_log_level";
+
+BackupableCommand::BackupableCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, false /* is_read_only */,
+                 BuildCmdLineOptions({ARG_BACKUP_ENV_URI, ARG_BACKUP_DIR,
+                                      ARG_NUM_THREADS, ARG_STDERR_LOG_LEVEL})),
+      num_threads_(1) {
+  auto itr = options.find(ARG_NUM_THREADS);
+  if (itr != options.end()) {
+    num_threads_ = std::stoi(itr->second);
+  }
+  itr = options.find(ARG_BACKUP_ENV_URI);
+  if (itr != options.end()) {
+    backup_env_uri_ = itr->second;
+  }
+  itr = options.find(ARG_BACKUP_DIR);
+  if (itr == options.end()) {
+    exec_state_ = LDBCommandExecuteResult::Failed("--" + ARG_BACKUP_DIR +
+                                                  ": missing backup directory");
+  } else {
+    backup_dir_ = itr->second;
+  }
+
+  itr = options.find(ARG_STDERR_LOG_LEVEL);
+  if (itr != options.end()) {
+    int stderr_log_level = std::stoi(itr->second);
+    if (stderr_log_level < 0 ||
+        stderr_log_level >= InfoLogLevel::NUM_INFO_LOG_LEVELS) {
+      exec_state_ = LDBCommandExecuteResult::Failed(
+          ARG_STDERR_LOG_LEVEL + " must be >= 0 and < " +
+          std::to_string(InfoLogLevel::NUM_INFO_LOG_LEVELS) + ".");
+    } else {
+      logger_.reset(
+          new StderrLogger(static_cast<InfoLogLevel>(stderr_log_level)));
+    }
+  }
+}
+
+void BackupableCommand::Help(const std::string& name, std::string& ret) {
+  ret.append("  ");
+  ret.append(name);
+  ret.append(" [--" + ARG_BACKUP_ENV_URI + "] ");
+  ret.append(" [--" + ARG_BACKUP_DIR + "] ");
+  ret.append(" [--" + ARG_NUM_THREADS + "] ");
+  ret.append(" [--" + ARG_STDERR_LOG_LEVEL + "=<int (InfoLogLevel)>] ");
+  ret.append("\n");
+}
+
+// ----------------------------------------------------------------------------
+
+BackupCommand::BackupCommand(const std::vector<std::string>& params,
+                             const std::map<std::string, std::string>& options,
+                             const std::vector<std::string>& flags)
+    : BackupableCommand(params, options, flags) {}
+
+void BackupCommand::Help(std::string& ret) {
+  BackupableCommand::Help(Name(), ret);
+}
+
+void BackupCommand::DoCommand() {
+  BackupEngine* backup_engine;
+  Status status;
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+  printf("open db OK\n");
+  std::unique_ptr<Env> custom_env_guard;
+  Env* custom_env = NewCustomObject<Env>(backup_env_uri_, &custom_env_guard);
+  BackupableDBOptions backup_options =
+      BackupableDBOptions(backup_dir_, custom_env);
+  backup_options.info_log = logger_.get();
+  backup_options.max_background_operations = num_threads_;
+  status = BackupEngine::Open(Env::Default(), backup_options, &backup_engine);
+  if (status.ok()) {
+    printf("open backup engine OK\n");
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(status.ToString());
+    return;
+  }
+  status = backup_engine->CreateNewBackup(db_);
+  if (status.ok()) {
+    printf("create new backup OK\n");
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(status.ToString());
+    return;
+  }
+}
+
+// ----------------------------------------------------------------------------
+
+RestoreCommand::RestoreCommand(
+    const std::vector<std::string>& params,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : BackupableCommand(params, options, flags) {}
+
+void RestoreCommand::Help(std::string& ret) {
+  BackupableCommand::Help(Name(), ret);
+}
+
+void RestoreCommand::DoCommand() {
+  std::unique_ptr<Env> custom_env_guard;
+  Env* custom_env = NewCustomObject<Env>(backup_env_uri_, &custom_env_guard);
+  std::unique_ptr<BackupEngineReadOnly> restore_engine;
+  Status status;
+  {
+    BackupableDBOptions opts(backup_dir_, custom_env);
+    opts.info_log = logger_.get();
+    opts.max_background_operations = num_threads_;
+    BackupEngineReadOnly* raw_restore_engine_ptr;
+    status = BackupEngineReadOnly::Open(Env::Default(), opts,
+                                        &raw_restore_engine_ptr);
+    if (status.ok()) {
+      restore_engine.reset(raw_restore_engine_ptr);
+    }
+  }
+  if (status.ok()) {
+    printf("open restore engine OK\n");
+    status = restore_engine->RestoreDBFromLatestBackup(db_path_, db_path_);
+  }
+  if (status.ok()) {
+    printf("restore from backup OK\n");
+  } else {
+    exec_state_ = LDBCommandExecuteResult::Failed(status.ToString());
+  }
+}
+
+// ----------------------------------------------------------------------------
+
+namespace {
+
+void DumpSstFile(Options options, std::string filename, bool output_hex,
+                 bool show_properties) {
+  std::string from_key;
+  std::string to_key;
+  if (filename.length() <= 4 ||
+      filename.rfind(".sst") != filename.length() - 4) {
+    std::cout << "Invalid sst file name." << std::endl;
+    return;
+  }
+  // no verification
+  rocksdb::SstFileDumper dumper(options, filename, false, output_hex);
+  Status st = dumper.ReadSequential(true, std::numeric_limits<uint64_t>::max(),
+                                    false,            // has_from
+                                    from_key, false,  // has_to
+                                    to_key);
+  if (!st.ok()) {
+    std::cerr << "Error in reading SST file " << filename << st.ToString()
+              << std::endl;
+    return;
+  }
+
+  if (show_properties) {
+    const rocksdb::TableProperties* table_properties;
+
+    std::shared_ptr<const rocksdb::TableProperties>
+        table_properties_from_reader;
+    st = dumper.ReadTableProperties(&table_properties_from_reader);
+    if (!st.ok()) {
+      std::cerr << filename << ": " << st.ToString()
+                << ". Try to use initial table properties" << std::endl;
+      table_properties = dumper.GetInitTableProperties();
+    } else {
+      table_properties = table_properties_from_reader.get();
+    }
+    if (table_properties != nullptr) {
+      std::cout << std::endl << "Table Properties:" << std::endl;
+      std::cout << table_properties->ToString("\n") << std::endl;
+    }
+  }
+}
+
+}  // namespace
+
+DBFileDumperCommand::DBFileDumperCommand(
+    const std::vector<std::string>& /*params*/,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(options, flags, true, BuildCmdLineOptions({})) {}
+
+void DBFileDumperCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(DBFileDumperCommand::Name());
+  ret.append("\n");
+}
+
+void DBFileDumperCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+  Status s;
+
+  std::cout << "Manifest File" << std::endl;
+  std::cout << "==============================" << std::endl;
+  std::string manifest_filename;
+  s = ReadFileToString(db_->GetEnv(), CurrentFileName(db_->GetName()),
+                       &manifest_filename);
+  if (!s.ok() || manifest_filename.empty() ||
+      manifest_filename.back() != '\n') {
+    std::cerr << "Error when reading CURRENT file "
+              << CurrentFileName(db_->GetName()) << std::endl;
+  }
+  // remove the trailing '\n'
+  manifest_filename.resize(manifest_filename.size() - 1);
+  std::string manifest_filepath = db_->GetName() + "/" + manifest_filename;
+  std::cout << manifest_filepath << std::endl;
+  DumpManifestFile(options_, manifest_filepath, false, false, false);
+  std::cout << std::endl;
+
+  std::cout << "SST Files" << std::endl;
+  std::cout << "==============================" << std::endl;
+  std::vector<LiveFileMetaData> metadata;
+  db_->GetLiveFilesMetaData(&metadata);
+  for (auto& fileMetadata : metadata) {
+    std::string filename = fileMetadata.db_path + fileMetadata.name;
+    std::cout << filename << " level:" << fileMetadata.level << std::endl;
+    std::cout << "------------------------------" << std::endl;
+    DumpSstFile(options_, filename, false, true);
+    std::cout << std::endl;
+  }
+  std::cout << std::endl;
+
+  std::cout << "Write Ahead Log Files" << std::endl;
+  std::cout << "==============================" << std::endl;
+  rocksdb::VectorLogPtr wal_files;
+  s = db_->GetSortedWalFiles(wal_files);
+  if (!s.ok()) {
+    std::cerr << "Error when getting WAL files" << std::endl;
+  } else {
+    for (auto& wal : wal_files) {
+      // TODO(qyang): option.wal_dir should be passed into ldb command
+      std::string filename = db_->GetOptions().wal_dir + wal->PathName();
+      std::cout << filename << std::endl;
+      // TODO(myabandeh): allow configuring is_write_commited
+      DumpWalFile(options_, filename, true, true, true /* is_write_commited */,
+                  &exec_state_);
+    }
+  }
+}
+
+void WriteExternalSstFilesCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(WriteExternalSstFilesCommand::Name());
+  ret.append(" <output_sst_path>");
+  ret.append("\n");
+}
+
+WriteExternalSstFilesCommand::WriteExternalSstFilesCommand(
+    const std::vector<std::string>& params,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(
+          options, flags, false /* is_read_only */,
+          BuildCmdLineOptions({ARG_HEX, ARG_KEY_HEX, ARG_VALUE_HEX, ARG_FROM,
+                               ARG_TO, ARG_CREATE_IF_MISSING})) {
+  create_if_missing_ =
+      IsFlagPresent(flags, ARG_CREATE_IF_MISSING) ||
+      ParseBooleanOption(options, ARG_CREATE_IF_MISSING, false);
+  if (params.size() != 1) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "output SST file path must be specified");
+  } else {
+    output_sst_path_ = params.at(0);
+  }
+}
+
+void WriteExternalSstFilesCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+  ColumnFamilyHandle* cfh = GetCfHandle();
+  SstFileWriter sst_file_writer(EnvOptions(), db_->GetOptions(), cfh);
+  Status status = sst_file_writer.Open(output_sst_path_);
+  if (!status.ok()) {
+    exec_state_ = LDBCommandExecuteResult::Failed("failed to open SST file: " +
+                                                  status.ToString());
+    return;
+  }
+
+  int bad_lines = 0;
+  std::string line;
+  std::ifstream ifs_stdin("/dev/stdin");
+  std::istream* istream_p = ifs_stdin.is_open() ? &ifs_stdin : &std::cin;
+  while (getline(*istream_p, line, '\n')) {
+    std::string key;
+    std::string value;
+    if (ParseKeyValue(line, &key, &value, is_key_hex_, is_value_hex_)) {
+      status = sst_file_writer.Put(key, value);
+      if (!status.ok()) {
+        exec_state_ = LDBCommandExecuteResult::Failed(
+            "failed to write record to file: " + status.ToString());
+        return;
+      }
+    } else if (0 == line.find("Keys in range:")) {
+      // ignore this line
+    } else if (0 == line.find("Created bg thread 0x")) {
+      // ignore this line
+    } else {
+      bad_lines++;
+    }
+  }
+
+  status = sst_file_writer.Finish();
+  if (!status.ok()) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "Failed to finish writing to file: " + status.ToString());
+    return;
+  }
+
+  if (bad_lines > 0) {
+    fprintf(stderr, "Warning: %d bad lines ignored.\n", bad_lines);
+  }
+  exec_state_ = LDBCommandExecuteResult::Succeed(
+      "external SST file written to " + output_sst_path_);
+}
+
+Options WriteExternalSstFilesCommand::PrepareOptionsForOpenDB() {
+  Options opt = LDBCommand::PrepareOptionsForOpenDB();
+  opt.create_if_missing = create_if_missing_;
+  return opt;
+}
+
+const std::string IngestExternalSstFilesCommand::ARG_MOVE_FILES = "move_files";
+const std::string IngestExternalSstFilesCommand::ARG_SNAPSHOT_CONSISTENCY =
+    "snapshot_consistency";
+const std::string IngestExternalSstFilesCommand::ARG_ALLOW_GLOBAL_SEQNO =
+    "allow_global_seqno";
+const std::string IngestExternalSstFilesCommand::ARG_ALLOW_BLOCKING_FLUSH =
+    "allow_blocking_flush";
+const std::string IngestExternalSstFilesCommand::ARG_INGEST_BEHIND =
+    "ingest_behind";
+const std::string IngestExternalSstFilesCommand::ARG_WRITE_GLOBAL_SEQNO =
+    "write_global_seqno";
+
+void IngestExternalSstFilesCommand::Help(std::string& ret) {
+  ret.append("  ");
+  ret.append(IngestExternalSstFilesCommand::Name());
+  ret.append(" <input_sst_path>");
+  ret.append(" [--" + ARG_MOVE_FILES + "] ");
+  ret.append(" [--" + ARG_SNAPSHOT_CONSISTENCY + "] ");
+  ret.append(" [--" + ARG_ALLOW_GLOBAL_SEQNO + "] ");
+  ret.append(" [--" + ARG_ALLOW_BLOCKING_FLUSH + "] ");
+  ret.append(" [--" + ARG_INGEST_BEHIND + "] ");
+  ret.append(" [--" + ARG_WRITE_GLOBAL_SEQNO + "] ");
+  ret.append("\n");
+}
+
+IngestExternalSstFilesCommand::IngestExternalSstFilesCommand(
+    const std::vector<std::string>& params,
+    const std::map<std::string, std::string>& options,
+    const std::vector<std::string>& flags)
+    : LDBCommand(
+          options, flags, false /* is_read_only */,
+          BuildCmdLineOptions({ARG_MOVE_FILES, ARG_SNAPSHOT_CONSISTENCY,
+                               ARG_ALLOW_GLOBAL_SEQNO, ARG_CREATE_IF_MISSING,
+                               ARG_ALLOW_BLOCKING_FLUSH, ARG_INGEST_BEHIND,
+                               ARG_WRITE_GLOBAL_SEQNO})),
+      move_files_(false),
+      snapshot_consistency_(true),
+      allow_global_seqno_(true),
+      allow_blocking_flush_(true),
+      ingest_behind_(false),
+      write_global_seqno_(true) {
+  create_if_missing_ =
+      IsFlagPresent(flags, ARG_CREATE_IF_MISSING) ||
+      ParseBooleanOption(options, ARG_CREATE_IF_MISSING, false);
+  move_files_ = IsFlagPresent(flags, ARG_MOVE_FILES) ||
+                ParseBooleanOption(options, ARG_MOVE_FILES, false);
+  snapshot_consistency_ =
+      IsFlagPresent(flags, ARG_SNAPSHOT_CONSISTENCY) ||
+      ParseBooleanOption(options, ARG_SNAPSHOT_CONSISTENCY, true);
+  allow_global_seqno_ =
+      IsFlagPresent(flags, ARG_ALLOW_GLOBAL_SEQNO) ||
+      ParseBooleanOption(options, ARG_ALLOW_GLOBAL_SEQNO, true);
+  allow_blocking_flush_ =
+      IsFlagPresent(flags, ARG_ALLOW_BLOCKING_FLUSH) ||
+      ParseBooleanOption(options, ARG_ALLOW_BLOCKING_FLUSH, true);
+  ingest_behind_ = IsFlagPresent(flags, ARG_INGEST_BEHIND) ||
+                   ParseBooleanOption(options, ARG_INGEST_BEHIND, false);
+  write_global_seqno_ =
+      IsFlagPresent(flags, ARG_WRITE_GLOBAL_SEQNO) ||
+      ParseBooleanOption(options, ARG_WRITE_GLOBAL_SEQNO, true);
+
+  if (allow_global_seqno_) {
+    if (!write_global_seqno_) {
+      fprintf(stderr,
+              "Warning: not writing global_seqno to the ingested SST can\n"
+              "prevent older versions of RocksDB from being able to open it\n");
+    }
+  } else {
+    if (write_global_seqno_) {
+      exec_state_ = LDBCommandExecuteResult::Failed(
+          "ldb cannot write global_seqno to the ingested SST when global_seqno "
+          "is not allowed");
+    }
+  }
+
+  if (params.size() != 1) {
+    exec_state_ =
+        LDBCommandExecuteResult::Failed("input SST path must be specified");
+  } else {
+    input_sst_path_ = params.at(0);
+  }
+}
+
+void IngestExternalSstFilesCommand::DoCommand() {
+  if (!db_) {
+    assert(GetExecuteState().IsFailed());
+    return;
+  }
+  if (GetExecuteState().IsFailed()) {
+    return;
+  }
+  ColumnFamilyHandle* cfh = GetCfHandle();
+  IngestExternalFileOptions ifo;
+  ifo.move_files = move_files_;
+  ifo.snapshot_consistency = snapshot_consistency_;
+  ifo.allow_global_seqno = allow_global_seqno_;
+  ifo.allow_blocking_flush = allow_blocking_flush_;
+  ifo.ingest_behind = ingest_behind_;
+  ifo.write_global_seqno = write_global_seqno_;
+  Status status = db_->IngestExternalFile(cfh, {input_sst_path_}, ifo);
+  if (!status.ok()) {
+    exec_state_ = LDBCommandExecuteResult::Failed(
+        "failed to ingest external SST: " + status.ToString());
+  } else {
+    exec_state_ =
+        LDBCommandExecuteResult::Succeed("external SST files ingested");
+  }
+}
+
+Options IngestExternalSstFilesCommand::PrepareOptionsForOpenDB() {
+  Options opt = LDBCommand::PrepareOptionsForOpenDB();
+  opt.create_if_missing = create_if_missing_;
+  return opt;
+}
+
+}   // namespace rocksdb
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/ldb_cmd_impl.h b/src/rocksdb/tools/ldb_cmd_impl.h
new file mode 100644
index 00000000..868c81f4
--- /dev/null
+++ b/src/rocksdb/tools/ldb_cmd_impl.h
@@ -0,0 +1,578 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#pragma once
+
+#include "rocksdb/utilities/ldb_cmd.h"
+
+#include <map>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace rocksdb {
+
+class CompactorCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "compact"; }
+
+  CompactorCommand(const std::vector<std::string>& params,
+                   const std::map<std::string, std::string>& options,
+                   const std::vector<std::string>& flags);
+
+  static void Help(std::string& ret);
+
+  virtual void DoCommand() override;
+
+ private:
+  bool null_from_;
+  std::string from_;
+  bool null_to_;
+  std::string to_;
+};
+
+class DBFileDumperCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "dump_live_files"; }
+
+  DBFileDumperCommand(const std::vector<std::string>& params,
+                      const std::map<std::string, std::string>& options,
+                      const std::vector<std::string>& flags);
+
+  static void Help(std::string& ret);
+
+  virtual void DoCommand() override;
+};
+
+class DBDumperCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "dump"; }
+
+  DBDumperCommand(const std::vector<std::string>& params,
+                  const std::map<std::string, std::string>& options,
+                  const std::vector<std::string>& flags);
+
+  static void Help(std::string& ret);
+
+  virtual void DoCommand() override;
+
+ private:
+  /**
+   * Extract file name from the full path. We handle both the forward slash (/)
+   * and backslash (\) to make sure that different OS-s are supported.
+  */
+  static std::string GetFileNameFromPath(const std::string& s) {
+    std::size_t n = s.find_last_of("/\\");
+
+    if (std::string::npos == n) {
+      return s;
+    } else {
+      return s.substr(n + 1);
+    }
+  }
+
+  void DoDumpCommand();
+
+  bool null_from_;
+  std::string from_;
+  bool null_to_;
+  std::string to_;
+  int max_keys_;
+  std::string delim_;
+  bool count_only_;
+  bool count_delim_;
+  bool print_stats_;
+  std::string path_;
+
+  static const std::string ARG_COUNT_ONLY;
+  static const std::string ARG_COUNT_DELIM;
+  static const std::string ARG_STATS;
+  static const std::string ARG_TTL_BUCKET;
+};
+
+class InternalDumpCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "idump"; }
+
+  InternalDumpCommand(const std::vector<std::string>& params,
+                      const std::map<std::string, std::string>& options,
+                      const std::vector<std::string>& flags);
+
+  static void Help(std::string& ret);
+
+  virtual void DoCommand() override;
+
+ private:
+  bool has_from_;
+  std::string from_;
+  bool has_to_;
+  std::string to_;
+  int max_keys_;
+  std::string delim_;
+  bool count_only_;
+  bool count_delim_;
+  bool print_stats_;
+  bool is_input_key_hex_;
+
+  static const std::string ARG_DELIM;
+  static const std::string ARG_COUNT_ONLY;
+  static const std::string ARG_COUNT_DELIM;
+  static const std::string ARG_STATS;
+  static const std::string ARG_INPUT_KEY_HEX;
+};
+
+class DBLoaderCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "load"; }
+
+  DBLoaderCommand(std::string& db_name, std::vector<std::string>& args);
+
+  DBLoaderCommand(const std::vector<std::string>& params,
+                  const std::map<std::string, std::string>& options,
+                  const std::vector<std::string>& flags);
+
+  static void Help(std::string& ret);
+  virtual void DoCommand() override;
+
+  virtual Options PrepareOptionsForOpenDB() override;
+
+ private:
+  bool disable_wal_;
+  bool bulk_load_;
+  bool compact_;
+
+  static const std::string ARG_DISABLE_WAL;
+  static const std::string ARG_BULK_LOAD;
+  static const std::string ARG_COMPACT;
+};
+
+class ManifestDumpCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "manifest_dump"; }
+
+  ManifestDumpCommand(const std::vector<std::string>& params,
+                      const std::map<std::string, std::string>& options,
+                      const std::vector<std::string>& flags);
+
+  static void Help(std::string& ret);
+  virtual void DoCommand() override;
+
+  virtual bool NoDBOpen() override { return true; }
+
+ private:
+  bool verbose_;
+  bool json_;
+  std::string path_;
+
+  static const std::string ARG_VERBOSE;
+  static const std::string ARG_JSON;
+  static const std::string ARG_PATH;
+};
+
+class ListColumnFamiliesCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "list_column_families"; }
+
+  ListColumnFamiliesCommand(const std::vector<std::string>& params,
+                            const std::map<std::string, std::string>& options,
+                            const std::vector<std::string>& flags);
+
+  static void Help(std::string& ret);
+  virtual void DoCommand() override;
+
+  virtual bool NoDBOpen() override { return true; }
+
+ private:
+  std::string dbname_;
+};
+
+class CreateColumnFamilyCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "create_column_family"; }
+
+  CreateColumnFamilyCommand(const std::vector<std::string>& params,
+                            const std::map<std::string, std::string>& options,
+                            const std::vector<std::string>& flags);
+
+  static void Help(std::string& ret);
+  virtual void DoCommand() override;
+
+  virtual bool NoDBOpen() override { return false; }
+
+ private:
+  std::string new_cf_name_;
+};
+
+class ReduceDBLevelsCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "reduce_levels"; }
+
+  ReduceDBLevelsCommand(const std::vector<std::string>& params,
+                        const std::map<std::string, std::string>& options,
+                        const std::vector<std::string>& flags);
+
+  virtual Options PrepareOptionsForOpenDB() override;
+
+  virtual void DoCommand() override;
+
+  virtual bool NoDBOpen() override { return true; }
+
+  static void Help(std::string& msg);
+
+  static std::vector<std::string> PrepareArgs(const std::string& db_path,
+                                              int new_levels,
+                                              bool print_old_level = false);
+
+ private:
+  int old_levels_;
+  int new_levels_;
+  bool print_old_levels_;
+
+  static const std::string ARG_NEW_LEVELS;
+  static const std::string ARG_PRINT_OLD_LEVELS;
+
+  Status GetOldNumOfLevels(Options& opt, int* levels);
+};
+
+class ChangeCompactionStyleCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "change_compaction_style"; }
+
+  ChangeCompactionStyleCommand(
+      const std::vector<std::string>& params,
+      const std::map<std::string, std::string>& options,
+      const std::vector<std::string>& flags);
+
+  virtual Options PrepareOptionsForOpenDB() override;
+
+  virtual void DoCommand() override;
+
+  static void Help(std::string& msg);
+
+ private:
+  int old_compaction_style_;
+  int new_compaction_style_;
+
+  static const std::string ARG_OLD_COMPACTION_STYLE;
+  static const std::string ARG_NEW_COMPACTION_STYLE;
+};
+
+class WALDumperCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "dump_wal"; }
+
+  WALDumperCommand(const std::vector<std::string>& params,
+                   const std::map<std::string, std::string>& options,
+                   const std::vector<std::string>& flags);
+
+  virtual bool NoDBOpen() override { return true; }
+
+  static void Help(std::string& ret);
+  virtual void DoCommand() override;
+
+ private:
+  bool print_header_;
+  std::string wal_file_;
+  bool print_values_;
+  bool is_write_committed_;  // default will be set to true
+
+  static const std::string ARG_WAL_FILE;
+  static const std::string ARG_WRITE_COMMITTED;
+  static const std::string ARG_PRINT_HEADER;
+  static const std::string ARG_PRINT_VALUE;
+};
+
+class GetCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "get"; }
+
+  GetCommand(const std::vector<std::string>& params,
+             const std::map<std::string, std::string>& options,
+             const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  static void Help(std::string& ret);
+
+ private:
+  std::string key_;
+};
+
+class ApproxSizeCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "approxsize"; }
+
+  ApproxSizeCommand(const std::vector<std::string>& params,
+                    const std::map<std::string, std::string>& options,
+                    const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  static void Help(std::string& ret);
+
+ private:
+  std::string start_key_;
+  std::string end_key_;
+};
+
+class BatchPutCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "batchput"; }
+
+  BatchPutCommand(const std::vector<std::string>& params,
+                  const std::map<std::string, std::string>& options,
+                  const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  static void Help(std::string& ret);
+
+  virtual Options PrepareOptionsForOpenDB() override;
+
+ private:
+  /**
+   * The key-values to be inserted.
+   */
+  std::vector<std::pair<std::string, std::string>> key_values_;
+};
+
+class ScanCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "scan"; }
+
+  ScanCommand(const std::vector<std::string>& params,
+              const std::map<std::string, std::string>& options,
+              const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  static void Help(std::string& ret);
+
+ private:
+  std::string start_key_;
+  std::string end_key_;
+  bool start_key_specified_;
+  bool end_key_specified_;
+  int max_keys_scanned_;
+  bool no_value_;
+};
+
+class DeleteCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "delete"; }
+
+  DeleteCommand(const std::vector<std::string>& params,
+                const std::map<std::string, std::string>& options,
+                const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  static void Help(std::string& ret);
+
+ private:
+  std::string key_;
+};
+
+class DeleteRangeCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "deleterange"; }
+
+  DeleteRangeCommand(const std::vector<std::string>& params,
+                     const std::map<std::string, std::string>& options,
+                     const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  static void Help(std::string& ret);
+
+ private:
+  std::string begin_key_;
+  std::string end_key_;
+};
+
+class PutCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "put"; }
+
+  PutCommand(const std::vector<std::string>& params,
+             const std::map<std::string, std::string>& options,
+             const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  static void Help(std::string& ret);
+
+  virtual Options PrepareOptionsForOpenDB() override;
+
+ private:
+  std::string key_;
+  std::string value_;
+};
+
+/**
+ * Command that starts up a REPL shell that allows
+ * get/put/delete.
+ */
+class DBQuerierCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "query"; }
+
+  DBQuerierCommand(const std::vector<std::string>& params,
+                   const std::map<std::string, std::string>& options,
+                   const std::vector<std::string>& flags);
+
+  static void Help(std::string& ret);
+
+  virtual void DoCommand() override;
+
+ private:
+  static const char* HELP_CMD;
+  static const char* GET_CMD;
+  static const char* PUT_CMD;
+  static const char* DELETE_CMD;
+};
+
+class CheckConsistencyCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "checkconsistency"; }
+
+  CheckConsistencyCommand(const std::vector<std::string>& params,
+                          const std::map<std::string, std::string>& options,
+                          const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  virtual bool NoDBOpen() override { return true; }
+
+  static void Help(std::string& ret);
+};
+
+class CheckPointCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "checkpoint"; }
+
+  CheckPointCommand(const std::vector<std::string>& params,
+                const std::map<std::string, std::string>& options,
+                const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  static void Help(std::string& ret);
+
+  std::string checkpoint_dir_;
+ private:
+  static const std::string ARG_CHECKPOINT_DIR;
+};
+
+class RepairCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "repair"; }
+
+  RepairCommand(const std::vector<std::string>& params,
+                const std::map<std::string, std::string>& options,
+                const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  virtual bool NoDBOpen() override { return true; }
+
+  static void Help(std::string& ret);
+};
+
+class BackupableCommand : public LDBCommand {
+ public:
+  BackupableCommand(const std::vector<std::string>& params,
+                    const std::map<std::string, std::string>& options,
+                    const std::vector<std::string>& flags);
+
+ protected:
+  static void Help(const std::string& name, std::string& ret);
+  std::string backup_env_uri_;
+  std::string backup_dir_;
+  int num_threads_;
+  std::unique_ptr<Logger> logger_;
+
+ private:
+  static const std::string ARG_BACKUP_DIR;
+  static const std::string ARG_BACKUP_ENV_URI;
+  static const std::string ARG_NUM_THREADS;
+  static const std::string ARG_STDERR_LOG_LEVEL;
+};
+
+class BackupCommand : public BackupableCommand {
+ public:
+  static std::string Name() { return "backup"; }
+  BackupCommand(const std::vector<std::string>& params,
+                const std::map<std::string, std::string>& options,
+                const std::vector<std::string>& flags);
+  virtual void DoCommand() override;
+  static void Help(std::string& ret);
+};
+
+class RestoreCommand : public BackupableCommand {
+ public:
+  static std::string Name() { return "restore"; }
+  RestoreCommand(const std::vector<std::string>& params,
+                 const std::map<std::string, std::string>& options,
+                 const std::vector<std::string>& flags);
+  virtual void DoCommand() override;
+  virtual bool NoDBOpen() override { return true; }
+  static void Help(std::string& ret);
+};
+
+class WriteExternalSstFilesCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "write_extern_sst"; }
+  WriteExternalSstFilesCommand(
+      const std::vector<std::string>& params,
+      const std::map<std::string, std::string>& options,
+      const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  virtual bool NoDBOpen() override { return false; }
+
+  virtual Options PrepareOptionsForOpenDB() override;
+
+  static void Help(std::string& ret);
+
+ private:
+  std::string output_sst_path_;
+};
+
+class IngestExternalSstFilesCommand : public LDBCommand {
+ public:
+  static std::string Name() { return "ingest_extern_sst"; }
+  IngestExternalSstFilesCommand(
+      const std::vector<std::string>& params,
+      const std::map<std::string, std::string>& options,
+      const std::vector<std::string>& flags);
+
+  virtual void DoCommand() override;
+
+  virtual bool NoDBOpen() override { return false; }
+
+  virtual Options PrepareOptionsForOpenDB() override;
+
+  static void Help(std::string& ret);
+
+ private:
+  std::string input_sst_path_;
+  bool move_files_;
+  bool snapshot_consistency_;
+  bool allow_global_seqno_;
+  bool allow_blocking_flush_;
+  bool ingest_behind_;
+  bool write_global_seqno_;
+
+  static const std::string ARG_MOVE_FILES;
+  static const std::string ARG_SNAPSHOT_CONSISTENCY;
+  static const std::string ARG_ALLOW_GLOBAL_SEQNO;
+  static const std::string ARG_ALLOW_BLOCKING_FLUSH;
+  static const std::string ARG_INGEST_BEHIND;
+  static const std::string ARG_WRITE_GLOBAL_SEQNO;
+};
+
+}  // namespace rocksdb
diff --git a/src/rocksdb/tools/ldb_cmd_test.cc b/src/rocksdb/tools/ldb_cmd_test.cc
new file mode 100644
index 00000000..3b709953
--- /dev/null
+++ b/src/rocksdb/tools/ldb_cmd_test.cc
@@ -0,0 +1,135 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+#ifndef ROCKSDB_LITE
+
+#include "rocksdb/utilities/ldb_cmd.h"
+#include "util/testharness.h"
+
+using std::string;
+using std::vector;
+using std::map;
+
+namespace rocksdb {
+
+class LdbCmdTest : public testing::Test {};
+
+TEST_F(LdbCmdTest, HexToString) {
+  // map input to expected outputs.
+  // odd number of "hex" half bytes doesn't make sense
+  map<string, vector<int>> inputMap = {
+      {"0x07", {7}},        {"0x5050", {80, 80}},          {"0xFF", {-1}},
+      {"0x1234", {18, 52}}, {"0xaaAbAC", {-86, -85, -84}}, {"0x1203", {18, 3}},
+  };
+
+  for (const auto& inPair : inputMap) {
+    auto actual = rocksdb::LDBCommand::HexToString(inPair.first);
+    auto expected = inPair.second;
+    for (unsigned int i = 0; i < actual.length(); i++) {
+      EXPECT_EQ(expected[i], static_cast<int>((signed char) actual[i]));
+    }
+    auto reverse = rocksdb::LDBCommand::StringToHex(actual);
+    EXPECT_STRCASEEQ(inPair.first.c_str(), reverse.c_str());
+  }
+}
+
+TEST_F(LdbCmdTest, HexToStringBadInputs) {
+  const vector<string> badInputs = {
+      "0xZZ", "123", "0xx5", "0x111G", "0x123", "Ox12", "0xT", "0x1Q1",
+  };
+  for (const auto badInput : badInputs) {
+    try {
+      rocksdb::LDBCommand::HexToString(badInput);
+      std::cerr << "Should fail on bad hex value: " << badInput << "\n";
+      FAIL();
+    } catch (...) {
+    }
+  }
+}
+
+TEST_F(LdbCmdTest, MemEnv) {
+  std::unique_ptr<Env> env(NewMemEnv(Env::Default()));
+  Options opts;
+  opts.env = env.get();
+  opts.create_if_missing = true;
+
+  DB* db = nullptr;
+  std::string dbname = test::TmpDir();
+  ASSERT_OK(DB::Open(opts, dbname, &db));
+
+  WriteOptions wopts;
+  for (int i = 0; i < 100; i++) {
+    char buf[16];
+    snprintf(buf, sizeof(buf), "%08d", i);
+    ASSERT_OK(db->Put(wopts, buf, buf));
+  }
+  FlushOptions fopts;
+  fopts.wait = true;
+  ASSERT_OK(db->Flush(fopts));
+
+  delete db;
+
+  char arg1[] = "./ldb";
+  char arg2[1024];
+  snprintf(arg2, sizeof(arg2), "--db=%s", dbname.c_str());
+  char arg3[] = "dump_live_files";
+  char* argv[] = {arg1, arg2, arg3};
+
+  rocksdb::LDBTool tool;
+  tool.Run(3, argv, opts);
+}
+
+TEST_F(LdbCmdTest, OptionParsing) {
+  // test parsing flags
+  {
+    std::vector<std::string> args;
+    args.push_back("scan");
+    args.push_back("--ttl");
+    args.push_back("--timestamp");
+    LDBCommand* command = rocksdb::LDBCommand::InitFromCmdLineArgs(
+        args, Options(), LDBOptions(), nullptr);
+    const std::vector<std::string> flags = command->TEST_GetFlags();
+    EXPECT_EQ(flags.size(), 2);
+    EXPECT_EQ(flags[0], "ttl");
+    EXPECT_EQ(flags[1], "timestamp");
+    delete command;
+  }
+  // test parsing options which contains equal sign in the option value
+  {
+    std::vector<std::string> args;
+    args.push_back("scan");
+    args.push_back("--db=/dev/shm/ldbtest/");
+    args.push_back(
+        "--from='abcd/efg/hijk/lmn/"
+        "opq:__rst.uvw.xyz?a=3+4+bcd+efghi&jk=lm_no&pq=rst-0&uv=wx-8&yz=a&bcd_"
+        "ef=gh.ijk'");
+    LDBCommand* command = rocksdb::LDBCommand::InitFromCmdLineArgs(
+        args, Options(), LDBOptions(), nullptr);
+    const std::map<std::string, std::string> option_map =
+        command->TEST_GetOptionMap();
+    EXPECT_EQ(option_map.at("db"), "/dev/shm/ldbtest/");
+    EXPECT_EQ(option_map.at("from"),
+              "'abcd/efg/hijk/lmn/"
+              "opq:__rst.uvw.xyz?a=3+4+bcd+efghi&jk=lm_no&pq=rst-0&uv=wx-8&yz="
+              "a&bcd_ef=gh.ijk'");
+    delete command;
+  }
+}
+
+} // namespace rocksdb
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
+#else
+#include <stdio.h>
+
+int main(int /*argc*/, char** /*argv*/) {
+  fprintf(stderr, "SKIPPED as LDBCommand is not supported in ROCKSDB_LITE\n");
+  return 0;
+}
+
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/ldb_test.py b/src/rocksdb/tools/ldb_test.py
new file mode 100644
index 00000000..2200fb46
--- /dev/null
+++ b/src/rocksdb/tools/ldb_test.py
@@ -0,0 +1,592 @@
+import os
+import glob
+import os.path
+import shutil
+import subprocess
+import time
+import unittest
+import tempfile
+import re
+
+def my_check_output(*popenargs, **kwargs):
+    """
+    If we had python 2.7, we should simply use subprocess.check_output.
+    This is a stop-gap solution for python 2.6
+    """
+    if 'stdout' in kwargs:
+        raise ValueError('stdout argument not allowed, it will be overridden.')
+    process = subprocess.Popen(stderr=subprocess.PIPE, stdout=subprocess.PIPE,
+                               *popenargs, **kwargs)
+    output, unused_err = process.communicate()
+    retcode = process.poll()
+    if retcode:
+        cmd = kwargs.get("args")
+        if cmd is None:
+            cmd = popenargs[0]
+        raise Exception("Exit code is not 0.  It is %d.  Command: %s" %
+                (retcode, cmd))
+    return output
+
+def run_err_null(cmd):
+    return os.system(cmd + " 2>/dev/null ")
+
+class LDBTestCase(unittest.TestCase):
+    def setUp(self):
+        self.TMP_DIR  = tempfile.mkdtemp(prefix="ldb_test_")
+        self.DB_NAME = "testdb"
+
+    def tearDown(self):
+        assert(self.TMP_DIR.strip() != "/"
+                and self.TMP_DIR.strip() != "/tmp"
+                and self.TMP_DIR.strip() != "/tmp/") #Just some paranoia
+
+        shutil.rmtree(self.TMP_DIR)
+
+    def dbParam(self, dbName):
+        return "--db=%s" % os.path.join(self.TMP_DIR, dbName)
+
+    def assertRunOKFull(self, params, expectedOutput, unexpected=False,
+                        isPattern=False):
+        """
+        All command-line params must be specified.
+        Allows full flexibility in testing; for example: missing db param.
+
+        """
+        output = my_check_output("./ldb %s |grep -v \"Created bg thread\"" %
+                            params, shell=True)
+        if not unexpected:
+            if isPattern:
+                self.assertNotEqual(expectedOutput.search(output.strip()),
+                                    None)
+            else:
+                self.assertEqual(output.strip(), expectedOutput.strip())
+        else:
+            if isPattern:
+                self.assertEqual(expectedOutput.search(output.strip()), None)
+            else:
+                self.assertNotEqual(output.strip(), expectedOutput.strip())
+
+    def assertRunFAILFull(self, params):
+        """
+        All command-line params must be specified.
+        Allows full flexibility in testing; for example: missing db param.
+
+        """
+        try:
+
+            my_check_output("./ldb %s >/dev/null 2>&1 |grep -v \"Created bg \
+                thread\"" % params, shell=True)
+        except Exception:
+            return
+        self.fail(
+            "Exception should have been raised for command with params: %s" %
+            params)
+
+    def assertRunOK(self, params, expectedOutput, unexpected=False):
+        """
+        Uses the default test db.
+
+        """
+        self.assertRunOKFull("%s %s" % (self.dbParam(self.DB_NAME), params),
+                             expectedOutput, unexpected)
+
+    def assertRunFAIL(self, params):
+        """
+        Uses the default test db.
+        """
+        self.assertRunFAILFull("%s %s" % (self.dbParam(self.DB_NAME), params))
+
+    def testSimpleStringPutGet(self):
+        print "Running testSimpleStringPutGet..."
+        self.assertRunFAIL("put x1 y1")
+        self.assertRunOK("put --create_if_missing x1 y1", "OK")
+        self.assertRunOK("get x1", "y1")
+        self.assertRunFAIL("get x2")
+
+        self.assertRunOK("put x2 y2", "OK")
+        self.assertRunOK("get x1", "y1")
+        self.assertRunOK("get x2", "y2")
+        self.assertRunFAIL("get x3")
+
+        self.assertRunOK("scan --from=x1 --to=z", "x1 : y1\nx2 : y2")
+        self.assertRunOK("put x3 y3", "OK")
+
+        self.assertRunOK("scan --from=x1 --to=z", "x1 : y1\nx2 : y2\nx3 : y3")
+        self.assertRunOK("scan", "x1 : y1\nx2 : y2\nx3 : y3")
+        self.assertRunOK("scan --from=x", "x1 : y1\nx2 : y2\nx3 : y3")
+
+        self.assertRunOK("scan --to=x2", "x1 : y1")
+        self.assertRunOK("scan --from=x1 --to=z --max_keys=1", "x1 : y1")
+        self.assertRunOK("scan --from=x1 --to=z --max_keys=2",
+                "x1 : y1\nx2 : y2")
+
+        self.assertRunOK("scan --from=x1 --to=z --max_keys=3",
+                "x1 : y1\nx2 : y2\nx3 : y3")
+        self.assertRunOK("scan --from=x1 --to=z --max_keys=4",
+                "x1 : y1\nx2 : y2\nx3 : y3")
+        self.assertRunOK("scan --from=x1 --to=x2", "x1 : y1")
+        self.assertRunOK("scan --from=x2 --to=x4", "x2 : y2\nx3 : y3")
+        self.assertRunFAIL("scan --from=x4 --to=z") # No results => FAIL
+        self.assertRunFAIL("scan --from=x1 --to=z --max_keys=foo")
+
+        self.assertRunOK("scan", "x1 : y1\nx2 : y2\nx3 : y3")
+
+        self.assertRunOK("delete x1", "OK")
+        self.assertRunOK("scan", "x2 : y2\nx3 : y3")
+
+        self.assertRunOK("delete NonExistentKey", "OK")
+        # It is weird that GET and SCAN raise exception for
+        # non-existent key, while delete does not
+
+        self.assertRunOK("checkconsistency", "OK")
+
+    def dumpDb(self, params, dumpFile):
+        return 0 == run_err_null("./ldb dump %s > %s" % (params, dumpFile))
+
+    def loadDb(self, params, dumpFile):
+        return 0 == run_err_null("cat %s | ./ldb load %s" % (dumpFile, params))
+
+    def writeExternSst(self, params, inputDumpFile, outputSst):
+        return 0 == run_err_null("cat %s | ./ldb write_extern_sst %s %s"
+                % (inputDumpFile, outputSst, params))
+
+    def ingestExternSst(self, params, inputSst):
+        return 0 == run_err_null("./ldb ingest_extern_sst %s %s"
+                                     % (inputSst, params))
+
+    def testStringBatchPut(self):
+        print "Running testStringBatchPut..."
+        self.assertRunOK("batchput x1 y1 --create_if_missing", "OK")
+        self.assertRunOK("scan", "x1 : y1")
+        self.assertRunOK("batchput x2 y2 x3 y3 \"x4 abc\" \"y4 xyz\"", "OK")
+        self.assertRunOK("scan", "x1 : y1\nx2 : y2\nx3 : y3\nx4 abc : y4 xyz")
+        self.assertRunFAIL("batchput")
+        self.assertRunFAIL("batchput k1")
+        self.assertRunFAIL("batchput k1 v1 k2")
+
+    def testCountDelimDump(self):
+        print "Running testCountDelimDump..."
+        self.assertRunOK("batchput x.1 x1 --create_if_missing", "OK")
+        self.assertRunOK("batchput y.abc abc y.2 2 z.13c pqr", "OK")
+        self.assertRunOK("dump --count_delim", "x => count:1\tsize:5\ny => count:2\tsize:12\nz => count:1\tsize:8")
+        self.assertRunOK("dump --count_delim=\".\"", "x => count:1\tsize:5\ny => count:2\tsize:12\nz => count:1\tsize:8")
+        self.assertRunOK("batchput x,2 x2 x,abc xabc", "OK")
+        self.assertRunOK("dump --count_delim=\",\"", "x => count:2\tsize:14\nx.1 => count:1\tsize:5\ny.2 => count:1\tsize:4\ny.abc => count:1\tsize:8\nz.13c => count:1\tsize:8")
+
+    def testCountDelimIDump(self):
+        print "Running testCountDelimIDump..."
+        self.assertRunOK("batchput x.1 x1 --create_if_missing", "OK")
+        self.assertRunOK("batchput y.abc abc y.2 2 z.13c pqr", "OK")
+        self.assertRunOK("idump --count_delim", "x => count:1\tsize:5\ny => count:2\tsize:12\nz => count:1\tsize:8")
+        self.assertRunOK("idump --count_delim=\".\"", "x => count:1\tsize:5\ny => count:2\tsize:12\nz => count:1\tsize:8")
+        self.assertRunOK("batchput x,2 x2 x,abc xabc", "OK")
+        self.assertRunOK("idump --count_delim=\",\"", "x => count:2\tsize:14\nx.1 => count:1\tsize:5\ny.2 => count:1\tsize:4\ny.abc => count:1\tsize:8\nz.13c => count:1\tsize:8")
+
+    def testInvalidCmdLines(self):
+        print "Running testInvalidCmdLines..."
+        # db not specified
+        self.assertRunFAILFull("put 0x6133 0x6233 --hex --create_if_missing")
+        # No param called he
+        self.assertRunFAIL("put 0x6133 0x6233 --he --create_if_missing")
+        # max_keys is not applicable for put
+        self.assertRunFAIL("put 0x6133 0x6233 --max_keys=1 --create_if_missing")
+        # hex has invalid boolean value
+
+    def testHexPutGet(self):
+        print "Running testHexPutGet..."
+        self.assertRunOK("put a1 b1 --create_if_missing", "OK")
+        self.assertRunOK("scan", "a1 : b1")
+        self.assertRunOK("scan --hex", "0x6131 : 0x6231")
+        self.assertRunFAIL("put --hex 6132 6232")
+        self.assertRunOK("put --hex 0x6132 0x6232", "OK")
+        self.assertRunOK("scan --hex", "0x6131 : 0x6231\n0x6132 : 0x6232")
+        self.assertRunOK("scan", "a1 : b1\na2 : b2")
+        self.assertRunOK("get a1", "b1")
+        self.assertRunOK("get --hex 0x6131", "0x6231")
+        self.assertRunOK("get a2", "b2")
+        self.assertRunOK("get --hex 0x6132", "0x6232")
+        self.assertRunOK("get --key_hex 0x6132", "b2")
+        self.assertRunOK("get --key_hex --value_hex 0x6132", "0x6232")
+        self.assertRunOK("get --value_hex a2", "0x6232")
+        self.assertRunOK("scan --key_hex --value_hex",
+                "0x6131 : 0x6231\n0x6132 : 0x6232")
+        self.assertRunOK("scan --hex --from=0x6131 --to=0x6133",
+                "0x6131 : 0x6231\n0x6132 : 0x6232")
+        self.assertRunOK("scan --hex --from=0x6131 --to=0x6132",
+                "0x6131 : 0x6231")
+        self.assertRunOK("scan --key_hex", "0x6131 : b1\n0x6132 : b2")
+        self.assertRunOK("scan --value_hex", "a1 : 0x6231\na2 : 0x6232")
+        self.assertRunOK("batchput --hex 0x6133 0x6233 0x6134 0x6234", "OK")
+        self.assertRunOK("scan", "a1 : b1\na2 : b2\na3 : b3\na4 : b4")
+        self.assertRunOK("delete --hex 0x6133", "OK")
+        self.assertRunOK("scan", "a1 : b1\na2 : b2\na4 : b4")
+        self.assertRunOK("checkconsistency", "OK")
+
+    def testTtlPutGet(self):
+        print "Running testTtlPutGet..."
+        self.assertRunOK("put a1 b1 --ttl --create_if_missing", "OK")
+        self.assertRunOK("scan --hex", "0x6131 : 0x6231", True)
+        self.assertRunOK("dump --ttl ", "a1 ==> b1", True)
+        self.assertRunOK("dump --hex --ttl ",
+                         "0x6131 ==> 0x6231\nKeys in range: 1")
+        self.assertRunOK("scan --hex --ttl", "0x6131 : 0x6231")
+        self.assertRunOK("get --value_hex a1", "0x6231", True)
+        self.assertRunOK("get --ttl a1", "b1")
+        self.assertRunOK("put a3 b3 --create_if_missing", "OK")
+        # fails because timstamp's length is greater than value's
+        self.assertRunFAIL("get --ttl a3")
+        self.assertRunOK("checkconsistency", "OK")
+
+    def testInvalidCmdLines(self):  # noqa: F811 T25377293 Grandfathered in
+        print "Running testInvalidCmdLines..."
+        # db not specified
+        self.assertRunFAILFull("put 0x6133 0x6233 --hex --create_if_missing")
+        # No param called he
+        self.assertRunFAIL("put 0x6133 0x6233 --he --create_if_missing")
+        # max_keys is not applicable for put
+        self.assertRunFAIL("put 0x6133 0x6233 --max_keys=1 --create_if_missing")
+        # hex has invalid boolean value
+        self.assertRunFAIL("put 0x6133 0x6233 --hex=Boo --create_if_missing")
+
+    def testDumpLoad(self):
+        print "Running testDumpLoad..."
+        self.assertRunOK("batchput --create_if_missing x1 y1 x2 y2 x3 y3 x4 y4",
+                "OK")
+        self.assertRunOK("scan", "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+        origDbPath = os.path.join(self.TMP_DIR, self.DB_NAME)
+
+        # Dump and load without any additional params specified
+        dumpFilePath = os.path.join(self.TMP_DIR, "dump1")
+        loadedDbPath = os.path.join(self.TMP_DIR, "loaded_from_dump1")
+        self.assertTrue(self.dumpDb("--db=%s" % origDbPath, dumpFilePath))
+        self.assertTrue(self.loadDb(
+            "--db=%s --create_if_missing" % loadedDbPath, dumpFilePath))
+        self.assertRunOKFull("scan --db=%s" % loadedDbPath,
+                "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+
+        # Dump and load in hex
+        dumpFilePath = os.path.join(self.TMP_DIR, "dump2")
+        loadedDbPath = os.path.join(self.TMP_DIR, "loaded_from_dump2")
+        self.assertTrue(self.dumpDb("--db=%s --hex" % origDbPath, dumpFilePath))
+        self.assertTrue(self.loadDb(
+            "--db=%s --hex --create_if_missing" % loadedDbPath, dumpFilePath))
+        self.assertRunOKFull("scan --db=%s" % loadedDbPath,
+                "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+
+        # Dump only a portion of the key range
+        dumpFilePath = os.path.join(self.TMP_DIR, "dump3")
+        loadedDbPath = os.path.join(self.TMP_DIR, "loaded_from_dump3")
+        self.assertTrue(self.dumpDb(
+            "--db=%s --from=x1 --to=x3" % origDbPath, dumpFilePath))
+        self.assertTrue(self.loadDb(
+            "--db=%s --create_if_missing" % loadedDbPath, dumpFilePath))
+        self.assertRunOKFull("scan --db=%s" % loadedDbPath, "x1 : y1\nx2 : y2")
+
+        # Dump upto max_keys rows
+        dumpFilePath = os.path.join(self.TMP_DIR, "dump4")
+        loadedDbPath = os.path.join(self.TMP_DIR, "loaded_from_dump4")
+        self.assertTrue(self.dumpDb(
+            "--db=%s --max_keys=3" % origDbPath, dumpFilePath))
+        self.assertTrue(self.loadDb(
+            "--db=%s --create_if_missing" % loadedDbPath, dumpFilePath))
+        self.assertRunOKFull("scan --db=%s" % loadedDbPath,
+                "x1 : y1\nx2 : y2\nx3 : y3")
+
+        # Load into an existing db, create_if_missing is not specified
+        self.assertTrue(self.dumpDb("--db=%s" % origDbPath, dumpFilePath))
+        self.assertTrue(self.loadDb("--db=%s" % loadedDbPath, dumpFilePath))
+        self.assertRunOKFull("scan --db=%s" % loadedDbPath,
+                "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+
+        # Dump and load with WAL disabled
+        dumpFilePath = os.path.join(self.TMP_DIR, "dump5")
+        loadedDbPath = os.path.join(self.TMP_DIR, "loaded_from_dump5")
+        self.assertTrue(self.dumpDb("--db=%s" % origDbPath, dumpFilePath))
+        self.assertTrue(self.loadDb(
+            "--db=%s --disable_wal --create_if_missing" % loadedDbPath,
+            dumpFilePath))
+        self.assertRunOKFull("scan --db=%s" % loadedDbPath,
+                "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+
+        # Dump and load with lots of extra params specified
+        extraParams = " ".join(["--bloom_bits=14", "--block_size=1024",
+                                "--auto_compaction=true",
+                                "--write_buffer_size=4194304",
+                                "--file_size=2097152"])
+        dumpFilePath = os.path.join(self.TMP_DIR, "dump6")
+        loadedDbPath = os.path.join(self.TMP_DIR, "loaded_from_dump6")
+        self.assertTrue(self.dumpDb(
+            "--db=%s %s" % (origDbPath, extraParams), dumpFilePath))
+        self.assertTrue(self.loadDb(
+            "--db=%s %s --create_if_missing" % (loadedDbPath, extraParams),
+            dumpFilePath))
+        self.assertRunOKFull("scan --db=%s" % loadedDbPath,
+                "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+
+        # Dump with count_only
+        dumpFilePath = os.path.join(self.TMP_DIR, "dump7")
+        loadedDbPath = os.path.join(self.TMP_DIR, "loaded_from_dump7")
+        self.assertTrue(self.dumpDb(
+            "--db=%s --count_only" % origDbPath, dumpFilePath))
+        self.assertTrue(self.loadDb(
+            "--db=%s --create_if_missing" % loadedDbPath, dumpFilePath))
+        # DB should have atleast one value for scan to work
+        self.assertRunOKFull("put --db=%s k1 v1" % loadedDbPath, "OK")
+        self.assertRunOKFull("scan --db=%s" % loadedDbPath, "k1 : v1")
+
+        # Dump command fails because of typo in params
+        dumpFilePath = os.path.join(self.TMP_DIR, "dump8")
+        self.assertFalse(self.dumpDb(
+            "--db=%s --create_if_missing" % origDbPath, dumpFilePath))
+
+    def testIDumpBasics(self):
+        print "Running testIDumpBasics..."
+        self.assertRunOK("put a val --create_if_missing", "OK")
+        self.assertRunOK("put b val", "OK")
+        self.assertRunOK(
+                "idump", "'a' seq:1, type:1 => val\n"
+                "'b' seq:2, type:1 => val\nInternal keys in range: 2")
+        self.assertRunOK(
+                "idump --input_key_hex --from=%s --to=%s" % (hex(ord('a')),
+                                                             hex(ord('b'))),
+                "'a' seq:1, type:1 => val\nInternal keys in range: 1")
+
+    def testMiscAdminTask(self):
+        print "Running testMiscAdminTask..."
+        # These tests need to be improved; for example with asserts about
+        # whether compaction or level reduction actually took place.
+        self.assertRunOK("batchput --create_if_missing x1 y1 x2 y2 x3 y3 x4 y4",
+                "OK")
+        self.assertRunOK("scan", "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+        origDbPath = os.path.join(self.TMP_DIR, self.DB_NAME)
+
+        self.assertTrue(0 == run_err_null(
+            "./ldb compact --db=%s" % origDbPath))
+        self.assertRunOK("scan", "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+
+        self.assertTrue(0 == run_err_null(
+            "./ldb reduce_levels --db=%s --new_levels=2" % origDbPath))
+        self.assertRunOK("scan", "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+
+        self.assertTrue(0 == run_err_null(
+            "./ldb reduce_levels --db=%s --new_levels=3" % origDbPath))
+        self.assertRunOK("scan", "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+
+        self.assertTrue(0 == run_err_null(
+            "./ldb compact --db=%s --from=x1 --to=x3" % origDbPath))
+        self.assertRunOK("scan", "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+
+        self.assertTrue(0 == run_err_null(
+            "./ldb compact --db=%s --hex --from=0x6131 --to=0x6134"
+            % origDbPath))
+        self.assertRunOK("scan", "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+
+        #TODO(dilip): Not sure what should be passed to WAL.Currently corrupted.
+        self.assertTrue(0 == run_err_null(
+            "./ldb dump_wal --db=%s --walfile=%s --header" % (
+                origDbPath, os.path.join(origDbPath, "LOG"))))
+        self.assertRunOK("scan", "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+
+    def testCheckConsistency(self):
+        print "Running testCheckConsistency..."
+
+        dbPath = os.path.join(self.TMP_DIR, self.DB_NAME)
+        self.assertRunOK("put x1 y1 --create_if_missing", "OK")
+        self.assertRunOK("put x2 y2", "OK")
+        self.assertRunOK("get x1", "y1")
+        self.assertRunOK("checkconsistency", "OK")
+
+        sstFilePath = my_check_output("ls %s" % os.path.join(dbPath, "*.sst"),
+                                      shell=True)
+
+        # Modify the file
+        my_check_output("echo 'evil' > %s" % sstFilePath, shell=True)
+        self.assertRunFAIL("checkconsistency")
+
+        # Delete the file
+        my_check_output("rm -f %s" % sstFilePath, shell=True)
+        self.assertRunFAIL("checkconsistency")
+
+    def dumpLiveFiles(self, params, dumpFile):
+        return 0 == run_err_null("./ldb dump_live_files %s > %s" % (
+            params, dumpFile))
+
+    def testDumpLiveFiles(self):
+        print "Running testDumpLiveFiles..."
+
+        dbPath = os.path.join(self.TMP_DIR, self.DB_NAME)
+        self.assertRunOK("put x1 y1 --create_if_missing", "OK")
+        self.assertRunOK("put x2 y2", "OK")
+        dumpFilePath = os.path.join(self.TMP_DIR, "dump1")
+        self.assertTrue(self.dumpLiveFiles("--db=%s" % dbPath, dumpFilePath))
+        self.assertRunOK("delete x1", "OK")
+        self.assertRunOK("put x3 y3", "OK")
+        dumpFilePath = os.path.join(self.TMP_DIR, "dump2")
+        self.assertTrue(self.dumpLiveFiles("--db=%s" % dbPath, dumpFilePath))
+
+    def getManifests(self, directory):
+        return glob.glob(directory + "/MANIFEST-*")
+
+    def getSSTFiles(self, directory):
+        return glob.glob(directory + "/*.sst")
+
+    def getWALFiles(self, directory):
+        return glob.glob(directory + "/*.log")
+
+    def copyManifests(self, src, dest):
+        return 0 == run_err_null("cp " + src + " " + dest)
+
+    def testManifestDump(self):
+        print "Running testManifestDump..."
+        dbPath = os.path.join(self.TMP_DIR, self.DB_NAME)
+        self.assertRunOK("put 1 1 --create_if_missing", "OK")
+        self.assertRunOK("put 2 2", "OK")
+        self.assertRunOK("put 3 3", "OK")
+        # Pattern to expect from manifest_dump.
+        num = "[0-9]+"
+        st = ".*"
+        subpat = st + " seq:" + num + ", type:" + num
+        regex = num + ":" + num + "\[" + subpat + ".." + subpat + "\]"
+        expected_pattern = re.compile(regex)
+        cmd = "manifest_dump --db=%s"
+        manifest_files = self.getManifests(dbPath)
+        self.assertTrue(len(manifest_files) == 1)
+        # Test with the default manifest file in dbPath.
+        self.assertRunOKFull(cmd % dbPath, expected_pattern,
+                             unexpected=False, isPattern=True)
+        self.copyManifests(manifest_files[0], manifest_files[0] + "1")
+        manifest_files = self.getManifests(dbPath)
+        self.assertTrue(len(manifest_files) == 2)
+        # Test with multiple manifest files in dbPath.
+        self.assertRunFAILFull(cmd % dbPath)
+        # Running it with the copy we just created should pass.
+        self.assertRunOKFull((cmd + " --path=%s")
+                             % (dbPath, manifest_files[1]),
+                             expected_pattern, unexpected=False,
+                             isPattern=True)
+        # Make sure that using the dump with --path will result in identical
+        # output as just using manifest_dump.
+        cmd = "dump --path=%s"
+        self.assertRunOKFull((cmd)
+                             % (manifest_files[1]),
+                             expected_pattern, unexpected=False,
+                             isPattern=True)
+
+    def testSSTDump(self):
+        print "Running testSSTDump..."
+
+        dbPath = os.path.join(self.TMP_DIR, self.DB_NAME)
+        self.assertRunOK("put sst1 sst1_val --create_if_missing", "OK")
+        self.assertRunOK("put sst2 sst2_val", "OK")
+        self.assertRunOK("get sst1", "sst1_val")
+
+        # Pattern to expect from SST dump.
+        regex = ".*Sst file format:.*"
+        expected_pattern = re.compile(regex)
+
+        sst_files = self.getSSTFiles(dbPath)
+        self.assertTrue(len(sst_files) >= 1)
+        cmd = "dump --path=%s"
+        self.assertRunOKFull((cmd)
+                             % (sst_files[0]),
+                             expected_pattern, unexpected=False,
+                             isPattern=True)
+
+    def testWALDump(self):
+        print "Running testWALDump..."
+
+        dbPath = os.path.join(self.TMP_DIR, self.DB_NAME)
+        self.assertRunOK("put wal1 wal1_val --create_if_missing", "OK")
+        self.assertRunOK("put wal2 wal2_val", "OK")
+        self.assertRunOK("get wal1", "wal1_val")
+
+        # Pattern to expect from WAL dump.
+        regex = "^Sequence,Count,ByteSize,Physical Offset,Key\(s\).*"
+        expected_pattern = re.compile(regex)
+
+        wal_files = self.getWALFiles(dbPath)
+        self.assertTrue(len(wal_files) >= 1)
+        cmd = "dump --path=%s"
+        self.assertRunOKFull((cmd)
+                             % (wal_files[0]),
+                             expected_pattern, unexpected=False,
+                             isPattern=True)
+
+    def testListColumnFamilies(self):
+        print "Running testListColumnFamilies..."
+        dbPath = os.path.join(self.TMP_DIR, self.DB_NAME)
+        self.assertRunOK("put x1 y1 --create_if_missing", "OK")
+        cmd = "list_column_families %s | grep -v \"Column families\""
+        # Test on valid dbPath.
+        self.assertRunOKFull(cmd % dbPath, "{default}")
+        # Test on empty path.
+        self.assertRunFAILFull(cmd % "")
+
+    def testColumnFamilies(self):
+        print "Running testColumnFamilies..."
+        dbPath = os.path.join(self.TMP_DIR, self.DB_NAME)  # noqa: F841 T25377293 Grandfathered in
+        self.assertRunOK("put cf1_1 1 --create_if_missing", "OK")
+        self.assertRunOK("put cf1_2 2 --create_if_missing", "OK")
+        self.assertRunOK("put cf1_3 3 --try_load_options", "OK")
+        # Given non-default column family to single CF DB.
+        self.assertRunFAIL("get cf1_1 --column_family=two")
+        self.assertRunOK("create_column_family two", "OK")
+        self.assertRunOK("put cf2_1 1 --create_if_missing --column_family=two",
+                         "OK")
+        self.assertRunOK("put cf2_2 2 --create_if_missing --column_family=two",
+                         "OK")
+        self.assertRunOK("delete cf1_2", "OK")
+        self.assertRunOK("create_column_family three", "OK")
+        self.assertRunOK("delete cf2_2 --column_family=two", "OK")
+        self.assertRunOK(
+            "put cf3_1 3 --create_if_missing --column_family=three",
+            "OK")
+        self.assertRunOK("get cf1_1 --column_family=default", "1")
+        self.assertRunOK("dump --column_family=two",
+                         "cf2_1 ==> 1\nKeys in range: 1")
+        self.assertRunOK("dump --column_family=two --try_load_options",
+                         "cf2_1 ==> 1\nKeys in range: 1")
+        self.assertRunOK("dump",
+                         "cf1_1 ==> 1\ncf1_3 ==> 3\nKeys in range: 2")
+        self.assertRunOK("get cf2_1 --column_family=two",
+                         "1")
+        self.assertRunOK("get cf3_1 --column_family=three",
+                         "3")
+        # non-existing column family.
+        self.assertRunFAIL("get cf3_1 --column_family=four")
+
+    def testIngestExternalSst(self):
+        print "Running testIngestExternalSst..."
+
+        # Dump, load, write external sst and ingest it in another db
+        dbPath = os.path.join(self.TMP_DIR, "db1")
+        self.assertRunOK(
+            "batchput --db=%s --create_if_missing x1 y1 x2 y2 x3 y3 x4 y4"
+            % dbPath,
+            "OK")
+        self.assertRunOK("scan --db=%s" % dbPath,
+                         "x1 : y1\nx2 : y2\nx3 : y3\nx4 : y4")
+        dumpFilePath = os.path.join(self.TMP_DIR, "dump1")
+        with open(dumpFilePath, 'w') as f:
+            f.write("x1 ==> y10\nx2 ==> y20\nx3 ==> y30\nx4 ==> y40")
+        externSstPath = os.path.join(self.TMP_DIR, "extern_data1.sst")
+        self.assertTrue(self.writeExternSst("--create_if_missing --db=%s"
+                            % dbPath,
+                        dumpFilePath,
+                        externSstPath))
+        # cannot ingest if allow_global_seqno is false
+        self.assertFalse(
+            self.ingestExternSst(
+                "--create_if_missing --allow_global_seqno=false --db=%s"
+                % dbPath,
+                externSstPath))
+        self.assertTrue(
+            self.ingestExternSst(
+                "--create_if_missing --allow_global_seqno --db=%s"
+                % dbPath,
+                externSstPath))
+        self.assertRunOKFull("scan --db=%s" % dbPath,
+                             "x1 : y10\nx2 : y20\nx3 : y30\nx4 : y40")
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/src/rocksdb/tools/ldb_tool.cc b/src/rocksdb/tools/ldb_tool.cc
new file mode 100644
index 00000000..fe307eab
--- /dev/null
+++ b/src/rocksdb/tools/ldb_tool.cc
@@ -0,0 +1,133 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+#ifndef ROCKSDB_LITE
+#include "rocksdb/ldb_tool.h"
+#include "rocksdb/utilities/ldb_cmd.h"
+#include "tools/ldb_cmd_impl.h"
+
+namespace rocksdb {
+
+LDBOptions::LDBOptions() {}
+
+void LDBCommandRunner::PrintHelp(const LDBOptions& ldb_options,
+                                 const char* /*exec_name*/) {
+  std::string ret;
+
+  ret.append(ldb_options.print_help_header);
+  ret.append("\n\n");
+  ret.append("commands MUST specify --" + LDBCommand::ARG_DB +
+             "=<full_path_to_db_directory> when necessary\n");
+  ret.append("\n");
+  ret.append(
+      "The following optional parameters control if keys/values are "
+      "input/output as hex or as plain strings:\n");
+  ret.append("  --" + LDBCommand::ARG_KEY_HEX +
+             " : Keys are input/output as hex\n");
+  ret.append("  --" + LDBCommand::ARG_VALUE_HEX +
+             " : Values are input/output as hex\n");
+  ret.append("  --" + LDBCommand::ARG_HEX +
+             " : Both keys and values are input/output as hex\n");
+  ret.append("\n");
+
+  ret.append(
+      "The following optional parameters control the database "
+      "internals:\n");
+  ret.append(
+      "  --" + LDBCommand::ARG_CF_NAME +
+      "=<string> : name of the column family to operate on. default: default "
+      "column family\n");
+  ret.append("  --" + LDBCommand::ARG_TTL +
+             " with 'put','get','scan','dump','query','batchput'"
+             " : DB supports ttl and value is internally timestamp-suffixed\n");
+  ret.append("  --" + LDBCommand::ARG_TRY_LOAD_OPTIONS +
+             " : Try to load option file from DB.\n");
+  ret.append("  --" + LDBCommand::ARG_IGNORE_UNKNOWN_OPTIONS +
+             " : Ignore unknown options when loading option file.\n");
+  ret.append("  --" + LDBCommand::ARG_BLOOM_BITS + "=<int,e.g.:14>\n");
+  ret.append("  --" + LDBCommand::ARG_FIX_PREFIX_LEN + "=<int,e.g.:14>\n");
+  ret.append("  --" + LDBCommand::ARG_COMPRESSION_TYPE +
+             "=<no|snappy|zlib|bzip2|lz4|lz4hc|xpress|zstd>\n");
+  ret.append("  --" + LDBCommand::ARG_COMPRESSION_MAX_DICT_BYTES +
+             "=<int,e.g.:16384>\n");
+  ret.append("  --" + LDBCommand::ARG_BLOCK_SIZE + "=<block_size_in_bytes>\n");
+  ret.append("  --" + LDBCommand::ARG_AUTO_COMPACTION + "=<true|false>\n");
+  ret.append("  --" + LDBCommand::ARG_DB_WRITE_BUFFER_SIZE +
+             "=<int,e.g.:16777216>\n");
+  ret.append("  --" + LDBCommand::ARG_WRITE_BUFFER_SIZE +
+             "=<int,e.g.:4194304>\n");
+  ret.append("  --" + LDBCommand::ARG_FILE_SIZE + "=<int,e.g.:2097152>\n");
+
+  ret.append("\n\n");
+  ret.append("Data Access Commands:\n");
+  PutCommand::Help(ret);
+  GetCommand::Help(ret);
+  BatchPutCommand::Help(ret);
+  ScanCommand::Help(ret);
+  DeleteCommand::Help(ret);
+  DeleteRangeCommand::Help(ret);
+  DBQuerierCommand::Help(ret);
+  ApproxSizeCommand::Help(ret);
+  CheckConsistencyCommand::Help(ret);
+
+  ret.append("\n\n");
+  ret.append("Admin Commands:\n");
+  WALDumperCommand::Help(ret);
+  CompactorCommand::Help(ret);
+  ReduceDBLevelsCommand::Help(ret);
+  ChangeCompactionStyleCommand::Help(ret);
+  DBDumperCommand::Help(ret);
+  DBLoaderCommand::Help(ret);
+  ManifestDumpCommand::Help(ret);
+  ListColumnFamiliesCommand::Help(ret);
+  DBFileDumperCommand::Help(ret);
+  InternalDumpCommand::Help(ret);
+  RepairCommand::Help(ret);
+  BackupCommand::Help(ret);
+  RestoreCommand::Help(ret);
+  CheckPointCommand::Help(ret);
+  WriteExternalSstFilesCommand::Help(ret);
+  IngestExternalSstFilesCommand::Help(ret);
+
+  fprintf(stderr, "%s\n", ret.c_str());
+}
+
+void LDBCommandRunner::RunCommand(
+    int argc, char** argv, Options options, const LDBOptions& ldb_options,
+    const std::vector<ColumnFamilyDescriptor>* column_families) {
+  if (argc <= 2) {
+    PrintHelp(ldb_options, argv[0]);
+    exit(1);
+  }
+
+  LDBCommand* cmdObj = LDBCommand::InitFromCmdLineArgs(
+      argc, argv, options, ldb_options, column_families);
+  if (cmdObj == nullptr) {
+    fprintf(stderr, "Unknown command\n");
+    PrintHelp(ldb_options, argv[0]);
+    exit(1);
+  }
+
+  if (!cmdObj->ValidateCmdLineOptions()) {
+    exit(1);
+  }
+
+  cmdObj->Run();
+  LDBCommandExecuteResult ret = cmdObj->GetExecuteState();
+  fprintf(stderr, "%s\n", ret.ToString().c_str());
+  delete cmdObj;
+
+  exit(ret.IsFailed());
+}
+
+void LDBTool::Run(int argc, char** argv, Options options,
+                  const LDBOptions& ldb_options,
+                  const std::vector<ColumnFamilyDescriptor>* column_families) {
+  LDBCommandRunner::RunCommand(argc, argv, options, ldb_options,
+                               column_families);
+}
+} // namespace rocksdb
+
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/pflag b/src/rocksdb/tools/pflag
new file mode 100755
index 00000000..f3394a66
--- /dev/null
+++ b/src/rocksdb/tools/pflag
@@ -0,0 +1,217 @@
+#!/usr/bin/env bash
+#
+#(c) 2004-present, Facebook, all rights reserved. 
+# See the LICENSE file for usage and distribution rights.
+#
+
+trap 'echo "Caught exception, dying"; exit' 1 2 3 15
+
+ME=`basename $0`
+SERVER=`hostname`
+
+#parameters used
+#
+Dump_Config=0
+DEBUG=
+OS=`/bin/uname -s`
+VMEM=
+RSS=
+CPU=
+VERBOSE=
+VAR=
+LIMIT=
+ACTION=
+N=
+WAIT=
+
+#
+#supported OS: Linux only for now. Easy to add
+#
+oscheck() {
+  case ${OS} in
+    Linux)
+     VMEM=vsz
+     RSS=rss
+     CPU=bsdtime
+     ;;
+    *)
+      die "Unsupported OS ${OS}. Send a bug report with OS you need supported. Thanks."
+      ;;
+  esac
+}
+
+
+verbose() {
+  if [ "x$DEBUG" != "x" ]; then
+    echo "$@" >&2
+  fi
+}
+
+warn() {
+  echo "$@" >&2
+}
+
+die() {
+    echo "ERROR: " "$@" >&2;
+    exit;
+}
+
+dump_config() {
+  cat <<EOCONFIG;
+$ME running on ${HOSTNAME} at `date`
+
+Configuration for this run:
+  PID to monitor     : ${PID}
+  Resource monitored : ${VAR}
+  Resource limit     : ${LIMIT}
+  Check every        : ${WAIT} seconds
+  No. of times run   : ${N}
+  What to do         : ${ACTION}
+EOCONFIG
+
+}
+
+usage() {
+  cat <<USAGE; exit
+$@
+
+Usage ${ME} -p pid [-x {VMEM|RSS|CPU}] -l limit [-a {warn|die|kill}] [-n cycles] [-w wait]
+
+Monitor a process for set of violations. Options:
+
+  -p: PID of process to monitor
+
+  -x: metric to sense. Currently only VMEM/RSS/CPU are supported. Defaults to VMEM
+
+  -l: what is the threshold/limit for the metric that is being sensed.
+    Examples: "-l 100m", "-l 1.5g" (for VMEM/RSS), "-l 5:04" 5:04 in BSDTIME for CPU
+    NOTE: defaults to 1GB
+
+  -a: action. Currently {warn|die|kill} are supported. 
+    The default action is to 'warn'. Here is the behavior:
+
+    warn: complain if usage exceeds threshold, but continue monitoring
+    kill: complain, kill the db_bench process and exit
+    die:  if usage exceeds threshold, die immediately
+
+  -n: number of cycles to monitor. Default is to monitor until PID no longer exists.
+
+  -w: wait time per cycle of monitoring. Default is 5 seconds.
+
+  -v: verbose messaging
+
+USAGE
+
+}
+
+#set default values if none given
+set_defaults_if_noopt_given() {
+
+  : ${VAR:=vsz}
+  : ${LIMIT:=1024000}
+  : ${WAIT:=5}
+  : ${N:=999999}
+  : ${ACTION:=warn}
+}
+
+validate_options() {
+  if [ "x$PID" = "x" -a $Dump_Config -ne 1 ]; then
+    usage "PID is mandatory"
+  fi
+}
+
+###### START
+
+
+  while getopts ":p:x:l:a:n:t:vhd" opt; do
+    case $opt in
+      d)
+          Dump_Config=1
+          ;;
+      h)
+          usage;
+          ;;
+      a)
+        ACTION=${OPTARG};
+        ;;
+      v)
+        DEBUG=1;
+        ;;
+      p)
+        PID=$OPTARG;
+        ;;
+      x)
+        VAR=$OPTARG;
+        ;;
+      l)
+        LIMIT=$OPTARG;
+        ;;
+      w)
+        WAIT=$OPTARG;
+        ;;
+      n)
+        N=$OPTARG;
+        ;;
+      \?) 
+        usage;
+        ;;
+    esac
+  done
+
+oscheck;
+set_defaults_if_noopt_given;
+validate_options;
+
+if [ $Dump_Config -eq 1 ]; then
+    dump_config;
+    exit;
+fi
+
+Done=0
+
+verbose "Trying ${N} times, Waiting ${WAIT} seconds each iteration";
+
+while [ $Done -eq 0 ]; do
+  VAL=`/bin/ps h -p $PID -o ${VAR} | perl -pe 'chomp; s/(.*)m/$1 * 1024/e; s/(.*)g/$1 * 1024 * 1024/e;'`
+  if [ ${VAL:=0} -eq 0 ]; then
+    warn "Process $PID ended without incident."
+    Done=1;
+    break;
+  fi
+
+  if [ $VAL -ge $LIMIT ]; then
+    Done=1;
+  else
+    echo "Value of '${VAR}' (${VAL}) is less than ${LIMIT} for PID ${PID}"
+    sleep $WAIT;
+  fi
+  if [ $Done -eq 1 ]; then
+
+    if [ "$ACTION" = "kill" ]; then
+        kill ${PID} || kill -3 ${PID}
+        exit;
+
+    elif [ "$ACTION" = "warn" ]; then
+
+      # go back to monitoring.
+
+      warn "`date` WARNING: ${VAR} breached threshold ${LIMIT}, actual is ${VAL}"
+      Done=0  #go back to monitoring
+
+    elif [ "$ACTION" = "die" ]; then
+      warn "WARNING: dying without killing process ${PID} on ${SERVER}"
+      warn "The process details are below: "
+      warn "`ps -p ${PID} -o pid,ppid,bsdtime,rss,vsz,cmd,args`"
+      warn ""
+
+      #should we send email/notify someone? TODO... for now, bail.
+
+      exit -1;
+
+    fi
+  else
+      :
+      #warn "INFO: PID $PID, $VAR = $VAL, limit ($LIMIT) not exceeded";
+  fi
+done
+
diff --git a/src/rocksdb/tools/rdb/.gitignore b/src/rocksdb/tools/rdb/.gitignore
new file mode 100644
index 00000000..378eac25
--- /dev/null
+++ b/src/rocksdb/tools/rdb/.gitignore
@@ -0,0 +1 @@
+build
diff --git a/src/rocksdb/tools/rdb/API.md b/src/rocksdb/tools/rdb/API.md
new file mode 100644
index 00000000..e9c2e592
--- /dev/null
+++ b/src/rocksdb/tools/rdb/API.md
@@ -0,0 +1,178 @@
+# JavaScript API
+
+## DBWrapper
+
+### Constructor
+
+    # Creates a new database wrapper object
+    RDB()
+
+### Open
+
+    # Open a new or existing RocksDB database.
+    #
+    # db_name         (string)   - Location of the database (inside the
+    #                              `/tmp` directory).
+    # column_families (string[]) - Names of additional column families
+    #                              beyond the default. If there are no other
+    #                              column families, this argument can be
+    #                              left off.
+    #
+    # Returns true if the database was opened successfully, or false otherwise
+    db_obj.(db_name, column_families = [])
+
+### Get
+
+    # Get the value of a given key.
+    #
+    # key           (string) - Which key to get the value of.
+    # column_family (string) - Which column family to check for the key.
+    #                          This argument can be left off for the default
+    #                          column family
+    #
+    # Returns the value (string) that is associated with the given key if
+    # one exists, or null otherwise.
+    db_obj.get(key, column_family = { default })
+
+### Put
+
+    # Associate a value with a key.
+    #
+    # key           (string) - Which key to associate the value with.
+    # value         (string) - The value to associate with the key.
+    # column_family (string) - Which column family to put the key-value pair
+    #                          in. This argument can be left off for the
+    #                          default column family.
+    #
+    # Returns true if the key-value pair was successfully stored in the
+    # database, or false otherwise.
+    db_obj.put(key, value, column_family = { default })
+
+### Delete
+
+    # Delete a value associated with a given key.
+    #
+    # key           (string) - Which key to delete the value of..
+    # column_family (string) - Which column family to check for the key.
+    #                          This argument can be left off for the default
+    #                          column family
+    #
+    # Returns true if an error occurred while trying to delete the key in
+    # the database, or false otherwise. Note that this is NOT the same as
+    # whether a value was deleted; in the case of a specified key not having
+    # a value, this will still return true. Use the `get` method prior to
+    # this method to check if a value existed before the call to `delete`.
+    db_obj.delete(key, column_family = { default })
+
+### Dump
+
+    # Print out all the key-value pairs in a given column family of the
+    # database.
+    #
+    # column_family (string) - Which column family to dump the pairs from.
+    #                          This argument can be left off for the default
+    #                          column family.
+    #
+    # Returns true if the keys were successfully read from the database, or
+    # false otherwise.
+    db_obj.dump(column_family = { default })
+
+### WriteBatch
+
+    # Execute an atomic batch of writes (i.e. puts and deletes) to the
+    # database.
+    #
+    # cf_batches (BatchObject[]; see below) - Put and Delete writes grouped
+    #                                         by column family to execute
+    #                                         atomically.
+    #
+    # Returns true if the argument array was well-formed and was
+    # successfully written to the database, or false otherwise.
+    db_obj.writeBatch(cf_batches)
+
+### CreateColumnFamily
+
+    # Create a new column family for the database.
+    #
+    # column_family_name (string) - Name of the new column family.
+    #
+    # Returns true if the new column family was successfully created, or
+    # false otherwise.
+    db_obj.createColumnFamily(column_family_name)
+
+### CompactRange
+
+    # Compact the underlying storage for a given range.
+    #
+    # In addition to the endpoints of the range, the method is overloaded to
+    # accept a non-default column family, a set of options, or both.
+    #
+    # begin (string)         - First key in the range to compact.
+    # end   (string)         - Last key in the range to compact.
+    # options (object)       - Contains a subset of the following key-value
+    #                          pairs:
+    #                            * 'target_level'   => int
+    #                            * 'target_path_id' => int
+    # column_family (string) - Which column family to compact the range in.
+    db_obj.compactRange(begin, end)
+    db_obj.compactRange(begin, end, options)
+    db_obj.compactRange(begin, end, column_family)
+    db_obj.compactRange(begin, end, options, column_family)
+
+
+
+### Close
+
+    # Close an a database and free the memory associated with it.
+    #
+    # Return null.
+    # db_obj.close()
+
+
+## BatchObject
+
+### Structure
+
+A BatchObject must have at least one of the following key-value pairs:
+
+* 'put' => Array of ['string1', 'string1'] pairs, each of which signifies that
+the key 'string1' should be associated with the value 'string2'
+* 'delete' => Array of strings, each of which is a key whose value should be
+deleted.
+
+The following key-value pair is optional:
+
+* 'column_family' => The name (string) of the column family to apply the
+changes to.
+
+### Examples
+
+    # Writes the key-value pairs 'firstname' => 'Saghm' and
+    # 'lastname' => 'Rossi' atomically to the database.
+    db_obj.writeBatch([
+        {
+            put: [ ['firstname', 'Saghm'], ['lastname', 'Rossi'] ]
+        }
+    ]);
+
+
+    # Deletes the values associated with 'firstname' and 'lastname' in
+    # the default column family and adds the key 'number_of_people' with
+    # with the value '2'. Additionally, adds the key-value pair
+    # 'name' => 'Saghm Rossi' to the column family 'user1' and the pair
+    # 'name' => 'Matt Blaze' to the column family 'user2'. All writes
+    # are done atomically.
+    db_obj.writeBatch([
+        {
+            put: [ ['number_of_people', '2'] ],
+            delete: ['firstname', 'lastname']
+        },
+        {
+            put: [ ['name', 'Saghm Rossi'] ],
+            column_family: 'user1'
+        },
+        {
+            put: [ ['name', Matt Blaze'] ],
+            column_family: 'user2'
+        }
+    ]);
diff --git a/src/rocksdb/tools/rdb/README.md b/src/rocksdb/tools/rdb/README.md
new file mode 100644
index 00000000..f69b3f7b
--- /dev/null
+++ b/src/rocksdb/tools/rdb/README.md
@@ -0,0 +1,40 @@
+# RDB - RocksDB Shell
+
+RDB is a NodeJS-based shell interface to RocksDB. It can also be used as a
+JavaScript binding for RocksDB within a Node application.
+
+## Setup/Compilation
+
+### Requirements
+
+* static RocksDB library (i.e. librocksdb.a)
+* libsnappy
+* node (tested onv0.10.33, no guarantees on anything else!)
+* node-gyp
+* python2 (for node-gyp; tested with 2.7.8)
+
+### Installation
+
+NOTE: If your default `python` binary is not a version of python2, add
+the arguments `--python /path/to/python2` to the `node-gyp` commands.
+
+1. Make sure you have the static library (i.e. "librocksdb.a") in the root
+directory of your rocksdb installation. If not, `cd` there and run
+`make static_lib`.
+
+2. Run `node-gyp configure` to generate the build.
+
+3. Run `node-gyp build` to compile RDB.
+
+## Usage
+
+### Running the shell
+
+Assuming everything compiled correctly, you can run the `rdb` executable
+located in the root of the `tools/rdb` directory to start the shell. The file is
+just a shell script that runs the node shell and loads the constructor for the
+RDB object into the top-level function `RDB`.
+
+### JavaScript API
+
+See `API.md` for how to use RocksDB from the shell.
diff --git a/src/rocksdb/tools/rdb/binding.gyp b/src/rocksdb/tools/rdb/binding.gyp
new file mode 100644
index 00000000..89145541
--- /dev/null
+++ b/src/rocksdb/tools/rdb/binding.gyp
@@ -0,0 +1,25 @@
+{
+    "targets": [
+        {
+            "target_name": "rdb",
+            "sources": [
+                "rdb.cc",
+                "db_wrapper.cc",
+                "db_wrapper.h"
+            ],
+            "cflags_cc!": [
+                "-fno-exceptions"
+            ],
+            "cflags_cc+": [
+                "-std=c++11",
+            ],
+            "include_dirs+": [
+                "../../include"
+            ],
+            "libraries": [
+                "../../../librocksdb.a",
+                "-lsnappy"
+            ],
+        }
+    ]
+}
diff --git a/src/rocksdb/tools/rdb/db_wrapper.cc b/src/rocksdb/tools/rdb/db_wrapper.cc
new file mode 100644
index 00000000..1ec9da1d
--- /dev/null
+++ b/src/rocksdb/tools/rdb/db_wrapper.cc
@@ -0,0 +1,525 @@
+#include <iostream>
+#include <memory>
+#include <vector>
+#include <v8.h>
+#include <node.h>
+
+#include "db/_wrapper.h"
+#include "rocksdb/db.h"
+#include "rocksdb/options.h"
+#include "rocksdb/slice.h"
+
+namespace {
+  void printWithBackSlashes(std::string str) {
+    for (std::string::size_type i = 0; i < str.size(); i++) {
+      if (str[i] == '\\' || str[i] == '"') {
+        std::cout << "\\";
+      }
+
+      std::cout << str[i];
+    }
+  }
+
+  bool has_key_for_array(Local<Object> obj, std::string key) {
+    return obj->Has(String::NewSymbol(key.c_str())) &&
+        obj->Get(String::NewSymbol(key.c_str()))->IsArray();
+  }
+}
+
+using namespace v8;
+
+
+Persistent<Function> DBWrapper::constructor;
+
+DBWrapper::DBWrapper() {
+  options_.IncreaseParallelism();
+  options_.OptimizeLevelStyleCompaction();
+  options_.disable_auto_compactions = true;
+  options_.create_if_missing = true;
+}
+
+DBWrapper::~DBWrapper() {
+  delete db_;
+}
+
+bool DBWrapper::HasFamilyNamed(std::string& name, DBWrapper* db) {
+  return db->columnFamilies_.find(name) != db->columnFamilies_.end();
+}
+
+
+void DBWrapper::Init(Handle<Object> exports) {
+  Local<FunctionTemplate> tpl = FunctionTemplate::New(New);
+  tpl->SetClassName(String::NewSymbol("DBWrapper"));
+  tpl->InstanceTemplate()->SetInternalFieldCount(8);
+  tpl->PrototypeTemplate()->Set(String::NewSymbol("open"),
+      FunctionTemplate::New(Open)->GetFunction());
+  tpl->PrototypeTemplate()->Set(String::NewSymbol("get"),
+      FunctionTemplate::New(Get)->GetFunction());
+  tpl->PrototypeTemplate()->Set(String::NewSymbol("put"),
+      FunctionTemplate::New(Put)->GetFunction());
+  tpl->PrototypeTemplate()->Set(String::NewSymbol("delete"),
+      FunctionTemplate::New(Delete)->GetFunction());
+  tpl->PrototypeTemplate()->Set(String::NewSymbol("dump"),
+      FunctionTemplate::New(Dump)->GetFunction());
+  tpl->PrototypeTemplate()->Set(String::NewSymbol("createColumnFamily"),
+      FunctionTemplate::New(CreateColumnFamily)->GetFunction());
+  tpl->PrototypeTemplate()->Set(String::NewSymbol("writeBatch"),
+      FunctionTemplate::New(WriteBatch)->GetFunction());
+  tpl->PrototypeTemplate()->Set(String::NewSymbol("compactRange"),
+      FunctionTemplate::New(CompactRange)->GetFunction());
+
+  constructor = Persistent<Function>::New(tpl->GetFunction());
+  exports->Set(String::NewSymbol("DBWrapper"), constructor);
+}
+
+Handle<Value> DBWrapper::Open(const Arguments& args) {
+  HandleScope scope;
+  DBWrapper* db_wrapper = ObjectWrap::Unwrap<DBWrapper>(args.This());
+
+  if (!(args[0]->IsString() &&
+       (args[1]->IsUndefined() || args[1]->IsArray()))) {
+    return scope.Close(Boolean::New(false));
+  }
+
+  std::string db_file = *v8::String::Utf8Value(args[0]->ToString());
+
+  std::vector<std::string> cfs = { rocksdb::kDefaultColumnFamilyName };
+
+  if (!args[1]->IsUndefined()) {
+    Handle<Array> array = Handle<Array>::Cast(args[1]);
+    for (uint i = 0; i < array->Length(); i++) {
+      if (!array->Get(i)->IsString()) {
+        return scope.Close(Boolean::New(false));
+      }
+
+      cfs.push_back(*v8::String::Utf8Value(array->Get(i)->ToString()));
+    }
+  }
+
+  if (cfs.size() == 1) {
+    db_wrapper->status_ = rocksdb::DB::Open(
+        db_wrapper->options_, db_file, &db_wrapper->db_);
+
+    return scope.Close(Boolean::New(db_wrapper->status_.ok()));
+  }
+
+  std::vector<rocksdb::ColumnFamilyDescriptor> families;
+
+  for (std::vector<int>::size_type i = 0; i < cfs.size(); i++) {
+    families.push_back(rocksdb::ColumnFamilyDescriptor(
+        cfs[i], rocksdb::ColumnFamilyOptions()));
+  }
+
+  std::vector<rocksdb::ColumnFamilyHandle*> handles;
+  db_wrapper->status_ = rocksdb::DB::Open(
+      db_wrapper->options_, db_file, families, &handles, &db_wrapper->db_);
+
+  if (!db_wrapper->status_.ok()) {
+    return scope.Close(Boolean::New(db_wrapper->status_.ok()));
+  }
+
+  for (std::vector<int>::size_type i = 0; i < handles.size(); i++) {
+    db_wrapper->columnFamilies_[cfs[i]] = handles[i];
+  }
+
+  return scope.Close(Boolean::New(true));
+}
+
+
+Handle<Value> DBWrapper::New(const Arguments& args) {
+  HandleScope scope;
+  Handle<Value> to_return;
+
+  if (args.IsConstructCall()) {
+    DBWrapper* db_wrapper = new DBWrapper();
+    db_wrapper->Wrap(args.This());
+
+    return args.This();
+  }
+
+  const int argc = 0;
+  Local<Value> argv[0] = {};
+
+  return scope.Close(constructor->NewInstance(argc, argv));
+}
+
+Handle<Value> DBWrapper::Get(const Arguments& args) {
+  HandleScope scope;
+
+  if (!(args[0]->IsString() &&
+        (args[1]->IsUndefined() || args[1]->IsString()))) {
+    return scope.Close(Null());
+  }
+
+  DBWrapper* db_wrapper = ObjectWrap::Unwrap<DBWrapper>(args.This());
+  std::string key       = *v8::String::Utf8Value(args[0]->ToString());
+  std::string cf        = *v8::String::Utf8Value(args[1]->ToString());
+  std::string value;
+
+  if (args[1]->IsUndefined()) {
+    db_wrapper->status_ = db_wrapper->db_->Get(
+        rocksdb::ReadOptions(), key, &value);
+  } else if (db_wrapper->HasFamilyNamed(cf, db_wrapper)) {
+    db_wrapper->status_ = db_wrapper->db_->Get(
+        rocksdb::ReadOptions(), db_wrapper->columnFamilies_[cf], key, &value);
+  } else {
+    return scope.Close(Null());
+  }
+
+  Handle<Value> v = db_wrapper->status_.ok() ?
+      String::NewSymbol(value.c_str()) : Null();
+
+  return scope.Close(v);
+}
+
+Handle<Value> DBWrapper::Put(const Arguments& args) {
+  HandleScope scope;
+
+  if (!(args[0]->IsString() && args[1]->IsString() &&
+       (args[2]->IsUndefined() || args[2]->IsString()))) {
+    return scope.Close(Boolean::New(false));
+  }
+
+  DBWrapper* db_wrapper = ObjectWrap::Unwrap<DBWrapper>(args.This());
+  std::string key       = *v8::String::Utf8Value(args[0]->ToString());
+  std::string value     = *v8::String::Utf8Value(args[1]->ToString());
+  std::string cf        = *v8::String::Utf8Value(args[2]->ToString());
+
+  if (args[2]->IsUndefined()) {
+    db_wrapper->status_  = db_wrapper->db_->Put(
+      rocksdb::WriteOptions(), key, value
+    );
+  } else if (db_wrapper->HasFamilyNamed(cf, db_wrapper)) {
+    db_wrapper->status_ = db_wrapper->db_->Put(
+      rocksdb::WriteOptions(),
+      db_wrapper->columnFamilies_[cf],
+      key,
+      value
+    );
+  } else {
+    return scope.Close(Boolean::New(false));
+  }
+
+
+  return scope.Close(Boolean::New(db_wrapper->status_.ok()));
+}
+
+Handle<Value> DBWrapper::Delete(const Arguments& args) {
+  HandleScope scope;
+
+  if (!args[0]->IsString()) {
+    return scope.Close(Boolean::New(false));
+  }
+
+  DBWrapper* db_wrapper = ObjectWrap::Unwrap<DBWrapper>(args.This());
+  std::string arg0      = *v8::String::Utf8Value(args[0]->ToString());
+  std::string arg1      = *v8::String::Utf8Value(args[1]->ToString());
+
+  if (args[1]->IsUndefined()) {
+    db_wrapper->status_ = db_wrapper->db_->Delete(
+        rocksdb::WriteOptions(), arg0);
+  } else {
+    if (!db_wrapper->HasFamilyNamed(arg1, db_wrapper)) {
+      return scope.Close(Boolean::New(false));
+    }
+    db_wrapper->status_ = db_wrapper->db_->Delete(
+        rocksdb::WriteOptions(), db_wrapper->columnFamilies_[arg1], arg0);
+  }
+
+  return scope.Close(Boolean::New(db_wrapper->status_.ok()));
+}
+
+Handle<Value> DBWrapper::Dump(const Arguments& args) {
+  HandleScope scope;
+  std::unique_ptr<rocksdb::Iterator> iterator;
+  DBWrapper* db_wrapper = ObjectWrap::Unwrap<DBWrapper>(args.This());
+  std::string arg0      = *v8::String::Utf8Value(args[0]->ToString());
+
+  if (args[0]->IsUndefined()) {
+    iterator.reset(db_wrapper->db_->NewIterator(rocksdb::ReadOptions()));
+  } else {
+    if (!db_wrapper->HasFamilyNamed(arg0, db_wrapper)) {
+      return scope.Close(Boolean::New(false));
+    }
+
+    iterator.reset(db_wrapper->db_->NewIterator(
+        rocksdb::ReadOptions(), db_wrapper->columnFamilies_[arg0]));
+  }
+
+  iterator->SeekToFirst();
+
+  while (iterator->Valid()) {
+    std::cout << "\"";
+    printWithBackSlashes(iterator->key().ToString());
+    std::cout << "\" => \"";
+    printWithBackSlashes(iterator->value().ToString());
+    std::cout << "\"\n";
+    iterator->Next();
+  }
+
+  return scope.Close(Boolean::New(true));
+}
+
+Handle<Value> DBWrapper::CreateColumnFamily(const Arguments& args) {
+  HandleScope scope;
+
+  if (!args[0]->IsString()) {
+    return scope.Close(Boolean::New(false));
+  }
+
+  DBWrapper* db_wrapper = ObjectWrap::Unwrap<DBWrapper>(args.This());
+  std::string cf_name   = *v8::String::Utf8Value(args[0]->ToString());
+
+  if (db_wrapper->HasFamilyNamed(cf_name, db_wrapper)) {
+    return scope.Close(Boolean::New(false));
+  }
+
+  rocksdb::ColumnFamilyHandle* cf;
+  db_wrapper->status_ = db_wrapper->db_->CreateColumnFamily(
+      rocksdb::ColumnFamilyOptions(), cf_name, &cf);
+
+  if (!db_wrapper->status_.ok()) {
+    return scope.Close(Boolean::New(false));
+  }
+
+  db_wrapper->columnFamilies_[cf_name] = cf;
+
+  return scope.Close(Boolean::New(true));
+}
+
+bool DBWrapper::AddToBatch(rocksdb::WriteBatch& batch, bool del,
+                           Handle<Array> array) {
+  Handle<Array> put_pair;
+  for (uint i = 0; i < array->Length(); i++) {
+    if (del) {
+      if (!array->Get(i)->IsString()) {
+        return false;
+      }
+
+      batch.Delete(*v8::String::Utf8Value(array->Get(i)->ToString()));
+      continue;
+    }
+
+    if (!array->Get(i)->IsArray()) {
+      return false;
+    }
+
+    put_pair = Handle<Array>::Cast(array->Get(i));
+
+    if (!put_pair->Get(0)->IsString() || !put_pair->Get(1)->IsString()) {
+      return false;
+    }
+
+    batch.Put(
+        *v8::String::Utf8Value(put_pair->Get(0)->ToString()),
+        *v8::String::Utf8Value(put_pair->Get(1)->ToString()));
+  }
+
+  return true;
+}
+
+bool DBWrapper::AddToBatch(rocksdb::WriteBatch& batch, bool del,
+                           Handle<Array> array, DBWrapper* db_wrapper,
+                           std::string cf) {
+  Handle<Array> put_pair;
+  for (uint i = 0; i < array->Length(); i++) {
+    if (del) {
+      if (!array->Get(i)->IsString()) {
+        return false;
+      }
+
+      batch.Delete(
+          db_wrapper->columnFamilies_[cf],
+          *v8::String::Utf8Value(array->Get(i)->ToString()));
+      continue;
+    }
+
+    if (!array->Get(i)->IsArray()) {
+      return false;
+    }
+
+    put_pair = Handle<Array>::Cast(array->Get(i));
+
+    if (!put_pair->Get(0)->IsString() || !put_pair->Get(1)->IsString()) {
+      return false;
+    }
+
+    batch.Put(
+        db_wrapper->columnFamilies_[cf],
+        *v8::String::Utf8Value(put_pair->Get(0)->ToString()),
+        *v8::String::Utf8Value(put_pair->Get(1)->ToString()));
+  }
+
+  return true;
+}
+
+Handle<Value> DBWrapper::WriteBatch(const Arguments& args) {
+  HandleScope scope;
+
+  if (!args[0]->IsArray()) {
+    return scope.Close(Boolean::New(false));
+  }
+
+  DBWrapper* db_wrapper     = ObjectWrap::Unwrap<DBWrapper>(args.This());
+  Handle<Array> sub_batches = Handle<Array>::Cast(args[0]);
+  Local<Object> sub_batch;
+  rocksdb::WriteBatch batch;
+  bool well_formed;
+
+  for (uint i = 0; i < sub_batches->Length(); i++) {
+    if (!sub_batches->Get(i)->IsObject()) {
+      return scope.Close(Boolean::New(false));
+    }
+    sub_batch = sub_batches->Get(i)->ToObject();
+
+    if (sub_batch->Has(String::NewSymbol("column_family"))) {
+      if (!has_key_for_array(sub_batch, "put") &&
+          !has_key_for_array(sub_batch, "delete")) {
+        return scope.Close(Boolean::New(false));
+      }
+
+      well_formed = db_wrapper->AddToBatch(
+        batch, false,
+        Handle<Array>::Cast(sub_batch->Get(String::NewSymbol("put"))),
+        db_wrapper, *v8::String::Utf8Value(sub_batch->Get(
+            String::NewSymbol("column_family"))));
+
+      well_formed = db_wrapper->AddToBatch(
+          batch, true,
+          Handle<Array>::Cast(sub_batch->Get(String::NewSymbol("delete"))),
+          db_wrapper, *v8::String::Utf8Value(sub_batch->Get(
+          String::NewSymbol("column_family"))));
+    } else {
+      well_formed = db_wrapper->AddToBatch(
+          batch, false,
+          Handle<Array>::Cast(sub_batch->Get(String::NewSymbol("put"))));
+      well_formed = db_wrapper->AddToBatch(
+          batch, true,
+          Handle<Array>::Cast(sub_batch->Get(String::NewSymbol("delete"))));
+
+      if (!well_formed) {
+        return scope.Close(Boolean::New(false));
+      }
+    }
+  }
+
+  db_wrapper->status_ = db_wrapper->db_->Write(rocksdb::WriteOptions(), &batch);
+
+  return scope.Close(Boolean::New(db_wrapper->status_.ok()));
+}
+
+Handle<Value> DBWrapper::CompactRangeDefault(const Arguments& args) {
+  HandleScope scope;
+
+  DBWrapper* db_wrapper = ObjectWrap::Unwrap<DBWrapper>(args.This());
+  rocksdb::Slice begin     = *v8::String::Utf8Value(args[0]->ToString());
+  rocksdb::Slice end       = *v8::String::Utf8Value(args[1]->ToString());
+  db_wrapper->status_    = db_wrapper->db_->CompactRange(&end, &begin);
+
+  return scope.Close(Boolean::New(db_wrapper->status_.ok()));
+}
+
+Handle<Value> DBWrapper::CompactColumnFamily(const Arguments& args) {
+  HandleScope scope;
+
+  DBWrapper* db_wrapper = ObjectWrap::Unwrap<DBWrapper>(args.This());
+  rocksdb::Slice begin  = *v8::String::Utf8Value(args[0]->ToString());
+  rocksdb::Slice end    = *v8::String::Utf8Value(args[1]->ToString());
+  std::string cf        = *v8::String::Utf8Value(args[2]->ToString());
+  db_wrapper->status_    = db_wrapper->db_->CompactRange(
+      db_wrapper->columnFamilies_[cf], &begin, &end);
+
+  return scope.Close(Boolean::New(db_wrapper->status_.ok()));
+}
+
+Handle<Value> DBWrapper::CompactOptions(const Arguments& args) {
+  HandleScope scope;
+
+  if (!args[2]->IsObject()) {
+    return scope.Close(Boolean::New(false));
+  }
+
+  DBWrapper* db_wrapper = ObjectWrap::Unwrap<DBWrapper>(args.This());
+  rocksdb::Slice begin     = *v8::String::Utf8Value(args[0]->ToString());
+  rocksdb::Slice end       = *v8::String::Utf8Value(args[1]->ToString());
+  Local<Object> options  = args[2]->ToObject();
+  int target_level = -1, target_path_id = 0;
+
+  if (options->Has(String::NewSymbol("target_level")) &&
+      options->Get(String::NewSymbol("target_level"))->IsInt32()) {
+    target_level = (int)(options->Get(
+        String::NewSymbol("target_level"))->ToInt32()->Value());
+
+    if (options->Has(String::NewSymbol("target_path_id")) ||
+        options->Get(String::NewSymbol("target_path_id"))->IsInt32()) {
+      target_path_id = (int)(options->Get(
+          String::NewSymbol("target_path_id"))->ToInt32()->Value());
+    }
+  }
+
+  db_wrapper->status_ = db_wrapper->db_->CompactRange(
+    &begin, &end, true, target_level, target_path_id
+  );
+
+  return scope.Close(Boolean::New(db_wrapper->status_.ok()));
+}
+
+Handle<Value> DBWrapper::CompactAll(const Arguments& args) {
+  HandleScope scope;
+
+  if (!args[2]->IsObject() || !args[3]->IsString()) {
+    return scope.Close(Boolean::New(false));
+  }
+
+  DBWrapper* db_wrapper = ObjectWrap::Unwrap<DBWrapper>(args.This());
+  rocksdb::Slice begin  = *v8::String::Utf8Value(args[0]->ToString());
+  rocksdb::Slice end    = *v8::String::Utf8Value(args[1]->ToString());
+  Local<Object> options = args[2]->ToObject();
+  std::string cf        = *v8::String::Utf8Value(args[3]->ToString());
+
+  int target_level = -1, target_path_id = 0;
+
+  if (options->Has(String::NewSymbol("target_level")) &&
+      options->Get(String::NewSymbol("target_level"))->IsInt32()) {
+    target_level = (int)(options->Get(
+        String::NewSymbol("target_level"))->ToInt32()->Value());
+
+    if (options->Has(String::NewSymbol("target_path_id")) ||
+        options->Get(String::NewSymbol("target_path_id"))->IsInt32()) {
+      target_path_id = (int)(options->Get(
+          String::NewSymbol("target_path_id"))->ToInt32()->Value());
+    }
+  }
+
+  db_wrapper->status_ = db_wrapper->db_->CompactRange(
+    db_wrapper->columnFamilies_[cf], &begin, &end, true, target_level,
+    target_path_id);
+
+  return scope.Close(Boolean::New(db_wrapper->status_.ok()));
+}
+
+Handle<Value> DBWrapper::CompactRange(const Arguments& args) {
+  HandleScope scope;
+
+  if (!args[0]->IsString() || !args[1]->IsString()) {
+    return scope.Close(Boolean::New(false));
+  }
+
+  switch(args.Length()) {
+  case 2:
+    return CompactRangeDefault(args);
+  case 3:
+    return args[2]->IsString() ? CompactColumnFamily(args) :
+        CompactOptions(args);
+  default:
+    return CompactAll(args);
+  }
+}
+
+Handle<Value> DBWrapper::Close(const Arguments& args) {
+  HandleScope scope;
+
+  delete ObjectWrap::Unwrap<DBWrapper>(args.This());
+
+  return scope.Close(Null());
+}
diff --git a/src/rocksdb/tools/rdb/db_wrapper.h b/src/rocksdb/tools/rdb/db_wrapper.h
new file mode 100644
index 00000000..9d1c8f88
--- /dev/null
+++ b/src/rocksdb/tools/rdb/db_wrapper.h
@@ -0,0 +1,58 @@
+#ifndef DBWRAPPER_H
+#define DBWRAPPER_H
+
+#include <map>
+#include <node.h>
+
+#include "rocksdb/db.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/options.h"
+
+using namespace v8;
+
+// Used to encapsulate a particular instance of an opened database.
+//
+// This object should not be used directly in C++; it exists solely to provide
+// a mapping from a JavaScript object to a C++ code that can use the RocksDB
+// API.
+class DBWrapper : public node::ObjectWrap {
+  public:
+    static void Init(Handle<Object> exports);
+
+  private:
+    explicit DBWrapper();
+    ~DBWrapper();
+
+    // Helper methods
+    static bool HasFamilyNamed(std::string& name, DBWrapper* db);
+    static bool AddToBatch(rocksdb::WriteBatch& batch, bool del,
+        Handle<Array> array);
+    static bool AddToBatch(rocksdb::WriteBatch& batch, bool del,
+        Handle<Array> array, DBWrapper* db_wrapper, std::string cf);
+    static Handle<Value> CompactRangeDefault(const v8::Arguments& args);
+    static Handle<Value> CompactColumnFamily(const Arguments& args);
+    static Handle<Value> CompactOptions(const Arguments& args);
+    static Handle<Value> CompactAll(const Arguments& args);
+
+    // C++ mappings of API methods
+    static Persistent<v8::Function> constructor;
+    static Handle<Value> Open(const Arguments& args);
+    static Handle<Value> New(const Arguments& args);
+    static Handle<Value> Get(const Arguments& args);
+    static Handle<Value> Put(const Arguments& args);
+    static Handle<Value> Delete(const Arguments& args);
+    static Handle<Value> Dump(const Arguments& args);
+    static Handle<Value> WriteBatch(const Arguments& args);
+    static Handle<Value> CreateColumnFamily(const Arguments& args);
+    static Handle<Value> CompactRange(const Arguments& args);
+    static Handle<Value> Close(const Arguments& args);
+
+    // Internal fields
+    rocksdb::Options options_;
+    rocksdb::Status status_;
+    rocksdb::DB* db_;
+    std::unordered_map<std::string, rocksdb::ColumnFamilyHandle*>
+        columnFamilies_;
+};
+
+#endif
diff --git a/src/rocksdb/tools/rdb/rdb b/src/rocksdb/tools/rdb/rdb
new file mode 100755
index 00000000..05da1158
--- /dev/null
+++ b/src/rocksdb/tools/rdb/rdb
@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+node -e "RDB = require('./build/Release/rdb').DBWrapper; console.log('Loaded rocksdb in variable RDB'); repl = require('repl').start('> ');"
diff --git a/src/rocksdb/tools/rdb/rdb.cc b/src/rocksdb/tools/rdb/rdb.cc
new file mode 100644
index 00000000..3619dc74
--- /dev/null
+++ b/src/rocksdb/tools/rdb/rdb.cc
@@ -0,0 +1,15 @@
+#ifndef BUILDING_NODE_EXTENSION
+#define BUILDING_NODE_EXTENSION
+#endif
+
+#include <node.h>
+#include <v8.h>
+#include "db/_wrapper.h"
+
+using namespace v8;
+
+void InitAll(Handle<Object> exports) {
+  DBWrapper::Init(exports);
+}
+
+NODE_MODULE(rdb, InitAll)
diff --git a/src/rocksdb/tools/rdb/unit_test.js b/src/rocksdb/tools/rdb/unit_test.js
new file mode 100644
index 00000000..d74ee8ce
--- /dev/null
+++ b/src/rocksdb/tools/rdb/unit_test.js
@@ -0,0 +1,124 @@
+assert = require('assert')
+RDB    = require('./build/Release/rdb').DBWrapper
+exec   = require('child_process').exec
+util   = require('util')
+
+DB_NAME = '/tmp/rocksdbtest-' + process.getuid()
+
+a = RDB()
+assert.equal(a.open(DB_NAME, ['b']), false)
+
+exec(
+    util.format(
+        "node -e \"RDB = require('./build/Release/rdb').DBWrapper; \
+        a = RDB('%s'); a.createColumnFamily('b')\"",
+        DB_NAME
+    ).exitCode, null
+)
+
+
+exec(
+    util.format(
+        "node -e \"RDB = require('./build/Release/rdb').DBWrapper; \
+        a = RDB('%s', ['b'])\"",
+        DB_NAME
+    ).exitCode, null
+)
+
+exec('rm -rf ' + DB_NAME)
+
+a = RDB()
+assert.equal(a.open(DB_NAME, ['a']), false)
+assert(a.open(DB_NAME), true)
+assert(a.createColumnFamily('temp'))
+
+b = RDB()
+assert.equal(b.open(DB_NAME), false)
+
+exec('rm -rf ' + DB_NAME)
+
+DB_NAME += 'b'
+
+a = RDB()
+assert(a.open(DB_NAME))
+assert.equal(a.constructor.name, 'DBWrapper')
+assert.equal(a.createColumnFamily(), false)
+assert.equal(a.createColumnFamily(1), false)
+assert.equal(a.createColumnFamily(['']), false)
+assert(a.createColumnFamily('b'))
+assert.equal(a.createColumnFamily('b'), false)
+
+// Get and Put
+assert.equal(a.get(1), null)
+assert.equal(a.get(['a']), null)
+assert.equal(a.get('a', 1), null)
+assert.equal(a.get(1, 'a'), null)
+assert.equal(a.get(1, 1), null)
+
+assert.equal(a.put(1), false)
+assert.equal(a.put(['a']), false)
+assert.equal(a.put('a', 1), false)
+assert.equal(a.put(1, 'a'), false)
+assert.equal(a.put(1, 1), false)
+assert.equal(a.put('a', 'a', 1), false)
+assert.equal(a.put('a', 1, 'a'), false)
+assert.equal(a.put(1, 'a', 'a'), false)
+assert.equal(a.put('a', 1, 1), false)
+assert.equal(a.put(1, 'a', 1), false)
+assert.equal(a.put(1, 1, 'a'), false)
+assert.equal(a.put(1, 1, 1), false)
+
+
+assert.equal(a.get(), null)
+assert.equal(a.get('a'), null)
+assert.equal(a.get('a', 'c'), null)
+assert.equal(a.put(), false)
+assert.equal(a.put('a'), false)
+assert.equal(a.get('a', 'b', 'c'), null)
+
+assert(a.put('a', 'axe'))
+assert(a.put('a', 'first'))
+assert.equal(a.get('a'), 'first')
+assert.equal(a.get('a', 'b'), null)
+assert.equal(a.get('a', 'c'), null)
+
+assert(a.put('a', 'apple', 'b'))
+assert.equal(a.get('a', 'b'), 'apple')
+assert.equal(a.get('a'), 'first')
+assert(a.put('b', 'butter', 'b'), 'butter')
+assert(a.put('b', 'banana', 'b'))
+assert.equal(a.get('b', 'b'), 'banana')
+assert.equal(a.get('b'), null)
+assert.equal(a.get('b', 'c'), null)
+
+// Delete
+assert.equal(a.delete(1), false)
+assert.equal(a.delete('a', 1), false)
+assert.equal(a.delete(1, 'a'), false)
+assert.equal(a.delete(1, 1), false)
+
+assert.equal(a.delete('b'), true)
+assert(a.delete('a'))
+assert.equal(a.get('a'), null)
+assert.equal(a.get('a', 'b'), 'apple')
+assert.equal(a.delete('c', 'c'), false)
+assert.equal(a.delete('c', 'b'), true)
+assert(a.delete('b', 'b'))
+assert.equal(a.get('b', 'b'), null)
+
+// Dump
+console.log("MARKER 1")
+assert(a.dump())
+console.log("Should be no output between 'MARKER 1' and here\n")
+console.log('Next line should be "a" => "apple"')
+assert(a.dump('b'))
+
+console.log("\nMARKER 2")
+assert.equal(a.dump('c'), false)
+console.log("Should be no output between 'MARKER 2' and here\n")
+
+// WriteBatch
+
+
+// Clean up test database
+exec('rm -rf ' + DB_NAME)
diff --git a/src/rocksdb/tools/reduce_levels_test.cc b/src/rocksdb/tools/reduce_levels_test.cc
new file mode 100644
index 00000000..1718b334
--- /dev/null
+++ b/src/rocksdb/tools/reduce_levels_test.cc
@@ -0,0 +1,218 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+
+#ifndef ROCKSDB_LITE
+
+#include "db/db_impl.h"
+#include "db/version_set.h"
+#include "rocksdb/db.h"
+#include "rocksdb/utilities/ldb_cmd.h"
+#include "tools/ldb_cmd_impl.h"
+#include "util/string_util.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+
+namespace rocksdb {
+
+class ReduceLevelTest : public testing::Test {
+public:
+  ReduceLevelTest() {
+    dbname_ = test::PerThreadDBPath("db_reduce_levels_test");
+    DestroyDB(dbname_, Options());
+    db_ = nullptr;
+  }
+
+  Status OpenDB(bool create_if_missing, int levels);
+
+  Status Put(const std::string& k, const std::string& v) {
+    return db_->Put(WriteOptions(), k, v);
+  }
+
+  std::string Get(const std::string& k) {
+    ReadOptions options;
+    std::string result;
+    Status s = db_->Get(options, k, &result);
+    if (s.IsNotFound()) {
+      result = "NOT_FOUND";
+    } else if (!s.ok()) {
+      result = s.ToString();
+    }
+    return result;
+  }
+
+  Status Flush() {
+    if (db_ == nullptr) {
+      return Status::InvalidArgument("DB not opened.");
+    }
+    DBImpl* db_impl = reinterpret_cast<DBImpl*>(db_);
+    return db_impl->TEST_FlushMemTable();
+  }
+
+  void MoveL0FileToLevel(int level) {
+    DBImpl* db_impl = reinterpret_cast<DBImpl*>(db_);
+    for (int i = 0; i < level; ++i) {
+      ASSERT_OK(db_impl->TEST_CompactRange(i, nullptr, nullptr));
+    }
+  }
+
+  void CloseDB() {
+    if (db_ != nullptr) {
+      delete db_;
+      db_ = nullptr;
+    }
+  }
+
+  bool ReduceLevels(int target_level);
+
+  int FilesOnLevel(int level) {
+    std::string property;
+    EXPECT_TRUE(db_->GetProperty(
+        "rocksdb.num-files-at-level" + NumberToString(level), &property));
+    return atoi(property.c_str());
+  }
+
+private:
+  std::string dbname_;
+  DB* db_;
+};
+
+Status ReduceLevelTest::OpenDB(bool create_if_missing, int num_levels) {
+  rocksdb::Options opt;
+  opt.num_levels = num_levels;
+  opt.create_if_missing = create_if_missing;
+  rocksdb::Status st = rocksdb::DB::Open(opt, dbname_, &db_);
+  if (!st.ok()) {
+    fprintf(stderr, "Can't open the db:%s\n", st.ToString().c_str());
+  }
+  return st;
+}
+
+bool ReduceLevelTest::ReduceLevels(int target_level) {
+  std::vector<std::string> args = rocksdb::ReduceDBLevelsCommand::PrepareArgs(
+      dbname_, target_level, false);
+  LDBCommand* level_reducer = LDBCommand::InitFromCmdLineArgs(
+      args, Options(), LDBOptions(), nullptr, LDBCommand::SelectCommand);
+  level_reducer->Run();
+  bool is_succeed = level_reducer->GetExecuteState().IsSucceed();
+  delete level_reducer;
+  return is_succeed;
+}
+
+TEST_F(ReduceLevelTest, Last_Level) {
+  ASSERT_OK(OpenDB(true, 4));
+  ASSERT_OK(Put("aaaa", "11111"));
+  Flush();
+  MoveL0FileToLevel(3);
+  ASSERT_EQ(FilesOnLevel(3), 1);
+  CloseDB();
+
+  ASSERT_TRUE(ReduceLevels(3));
+  ASSERT_OK(OpenDB(true, 3));
+  ASSERT_EQ(FilesOnLevel(2), 1);
+  CloseDB();
+
+  ASSERT_TRUE(ReduceLevels(2));
+  ASSERT_OK(OpenDB(true, 2));
+  ASSERT_EQ(FilesOnLevel(1), 1);
+  CloseDB();
+}
+
+TEST_F(ReduceLevelTest, Top_Level) {
+  ASSERT_OK(OpenDB(true, 5));
+  ASSERT_OK(Put("aaaa", "11111"));
+  Flush();
+  ASSERT_EQ(FilesOnLevel(0), 1);
+  CloseDB();
+
+  ASSERT_TRUE(ReduceLevels(4));
+  ASSERT_OK(OpenDB(true, 4));
+  CloseDB();
+
+  ASSERT_TRUE(ReduceLevels(3));
+  ASSERT_OK(OpenDB(true, 3));
+  CloseDB();
+
+  ASSERT_TRUE(ReduceLevels(2));
+  ASSERT_OK(OpenDB(true, 2));
+  CloseDB();
+}
+
+TEST_F(ReduceLevelTest, All_Levels) {
+  ASSERT_OK(OpenDB(true, 5));
+  ASSERT_OK(Put("a", "a11111"));
+  ASSERT_OK(Flush());
+  MoveL0FileToLevel(4);
+  ASSERT_EQ(FilesOnLevel(4), 1);
+  CloseDB();
+
+  ASSERT_OK(OpenDB(true, 5));
+  ASSERT_OK(Put("b", "b11111"));
+  ASSERT_OK(Flush());
+  MoveL0FileToLevel(3);
+  ASSERT_EQ(FilesOnLevel(3), 1);
+  ASSERT_EQ(FilesOnLevel(4), 1);
+  CloseDB();
+
+  ASSERT_OK(OpenDB(true, 5));
+  ASSERT_OK(Put("c", "c11111"));
+  ASSERT_OK(Flush());
+  MoveL0FileToLevel(2);
+  ASSERT_EQ(FilesOnLevel(2), 1);
+  ASSERT_EQ(FilesOnLevel(3), 1);
+  ASSERT_EQ(FilesOnLevel(4), 1);
+  CloseDB();
+
+  ASSERT_OK(OpenDB(true, 5));
+  ASSERT_OK(Put("d", "d11111"));
+  ASSERT_OK(Flush());
+  MoveL0FileToLevel(1);
+  ASSERT_EQ(FilesOnLevel(1), 1);
+  ASSERT_EQ(FilesOnLevel(2), 1);
+  ASSERT_EQ(FilesOnLevel(3), 1);
+  ASSERT_EQ(FilesOnLevel(4), 1);
+  CloseDB();
+
+  ASSERT_TRUE(ReduceLevels(4));
+  ASSERT_OK(OpenDB(true, 4));
+  ASSERT_EQ("a11111", Get("a"));
+  ASSERT_EQ("b11111", Get("b"));
+  ASSERT_EQ("c11111", Get("c"));
+  ASSERT_EQ("d11111", Get("d"));
+  CloseDB();
+
+  ASSERT_TRUE(ReduceLevels(3));
+  ASSERT_OK(OpenDB(true, 3));
+  ASSERT_EQ("a11111", Get("a"));
+  ASSERT_EQ("b11111", Get("b"));
+  ASSERT_EQ("c11111", Get("c"));
+  ASSERT_EQ("d11111", Get("d"));
+  CloseDB();
+
+  ASSERT_TRUE(ReduceLevels(2));
+  ASSERT_OK(OpenDB(true, 2));
+  ASSERT_EQ("a11111", Get("a"));
+  ASSERT_EQ("b11111", Get("b"));
+  ASSERT_EQ("c11111", Get("c"));
+  ASSERT_EQ("d11111", Get("d"));
+  CloseDB();
+}
+
+}
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
+
+#else
+#include <stdio.h>
+
+int main(int /*argc*/, char** /*argv*/) {
+  fprintf(stderr, "SKIPPED as LDBCommand is not supported in ROCKSDB_LITE\n");
+  return 0;
+}
+
+#endif  // !ROCKSDB_LITE
diff --git a/src/rocksdb/tools/regression_test.sh b/src/rocksdb/tools/regression_test.sh
new file mode 100755
index 00000000..69a53a47
--- /dev/null
+++ b/src/rocksdb/tools/regression_test.sh
@@ -0,0 +1,469 @@
+#!/usr/bin/env bash
+# The RocksDB regression test script.
+# REQUIREMENT: must be able to run make db_bench in the current directory
+#
+# This script will do the following things in order:
+#
+# 1. check out the specified rocksdb commit.
+# 2. build db_bench using the specified commit
+# 3. setup test directory $TEST_PATH.  If not specified, then the test directory
+#    will be "/tmp/rocksdb/regression_test"
+# 4. run set of benchmarks on the specified host
+#    (can be either locally or remotely)
+# 5. generate report in the $RESULT_PATH.  If RESULT_PATH is not specified,
+#    RESULT_PATH will be set to $TEST_PATH/current_time
+#
+# = Examples =
+# * Run the regression test using rocksdb commit abcdef that outputs results
+#   and temp files in "/my/output/dir"
+#r
+#   TEST_PATH=/my/output/dir COMMIT_ID=abcdef ./tools/regression_test.sh
+#
+# * Run the regression test on a remost host under "/my/output/dir" directory
+#   and stores the result locally in "/my/benchmark/results" using commit
+#   abcdef and with the rocksdb options specified in /my/path/to/OPTIONS-012345
+#   with 1000000000 keys in each benchmark in the regression test where each
+#   key and value are 100 and 900 bytes respectively:
+#
+#   REMOTE_USER_AT_HOST=yhchiang@my.remote.host \
+#       TEST_PATH=/my/output/dir \
+#       RESULT_PATH=/my/benchmark/results \
+#       COMMIT_ID=abcdef \
+#       OPTIONS_FILE=/my/path/to/OPTIONS-012345 \
+#       NUM_KEYS=1000000000 \
+#       KEY_SIZE=100 \
+#       VALUE_SIZE=900 \
+#       ./tools/regression_test.sh
+#
+# = Regression test environmental parameters =
+#   DEBUG: If true, then the script will not checkout master and build db_bench
+#       if db_bench already exists
+#       Default: 0
+#   TEST_MODE: If 1, run fillseqdeterminstic and benchmarks both
+#       if 0, only run fillseqdeterministc
+#       if 2, only run benchmarks
+#       Default: 1
+#   TEST_PATH: the root directory of the regression test.
+#       Default: "/tmp/rocksdb/regression_test"
+#   RESULT_PATH: the directory where the regression results will be generated.
+#       Default: "$TEST_PATH/current_time"
+#   REMOTE_USER_AT_HOST: If set, then test will run on the specified host under
+#       TEST_PATH directory and outputs test results locally in RESULT_PATH
+#       The REMOTE_USER_AT_HOST should follow the format user-id@host.name
+#   DB_PATH: the path where the rocksdb database will be created during the
+#       regression test.  Default:  $TEST_PATH/db
+#   WAL_PATH: the path where the rocksdb WAL will be outputed.
+#       Default:  $TEST_PATH/wal
+#   OPTIONS_FILE:  If specified, then the regression test will use the specified
+#       file to initialize the RocksDB options in its benchmarks.  Note that
+#       this feature only work for commits after 88acd93 or rocksdb version
+#       later than 4.9.
+#   DELETE_TEST_PATH: If true, then the test directory will be deleted
+#       after the script ends.
+#       Default: 0
+#
+# = db_bench parameters =
+#   NUM_THREADS:  The number of concurrent foreground threads that will issue
+#       database operations in the benchmark.  Default: 16.
+#   NUM_KEYS:  The key range that will be used in the entire regression test.
+#       Default: 1G.
+#   NUM_OPS:  The number of operations (reads, writes, or deletes) that will
+#       be issued in EACH thread.
+#       Default: $NUM_KEYS / $NUM_THREADS
+#   KEY_SIZE:  The size of each key in bytes in db_bench.  Default: 100.
+#   VALUE_SIZE:  The size of each value in bytes in db_bench.  Default: 900.
+#   CACHE_SIZE:  The size of RocksDB block cache used in db_bench.  Default: 1G
+#   STATISTICS:  If 1, then statistics is on in db_bench.  Default: 0.
+#   COMPRESSION_RATIO:  The compression ratio of the key generated in db_bench.
+#       Default: 0.5.
+#   HISTOGRAM:  If 1, then the histogram feature on performance feature is on.
+#   STATS_PER_INTERVAL:  If 1, then the statistics will be reported for every
+#       STATS_INTERVAL_SECONDS seconds.  Default 1.
+#   STATS_INTERVAL_SECONDS:  If STATS_PER_INTERVAL is set to 1, then statistics
+#       will be reported for every STATS_INTERVAL_SECONDS.  Default 60.
+#   MAX_BACKGROUND_FLUSHES:  The maxinum number of concurrent flushes in
+#       db_bench.  Default: 4.
+#   MAX_BACKGROUND_COMPACTIONS:  The maximum number of concurrent compactions
+#       in db_bench.  Default: 16.
+#   NUM_HIGH_PRI_THREADS:  The number of high-pri threads available for
+#       concurrent flushes in db_bench.  Default: 4.
+#   NUM_LOW_PRI_THREADS:  The number of low-pri threads available for
+#       concurrent compactions in db_bench.  Default: 16.
+#   SEEK_NEXTS:  Controls how many Next() will be called after seek.
+#       Default: 10.
+#   SEED:  random seed that controls the randomness of the benchmark.
+#       Default: $( date +%s )
+
+#==============================================================================
+#  CONSTANT
+#==============================================================================
+TITLE_FORMAT="%40s,%25s,%30s,%7s,%9s,%8s,"
+TITLE_FORMAT+="%10s,%13s,%14s,%11s,%12s,"
+TITLE_FORMAT+="%7s,%11s,"
+TITLE_FORMAT+="%9s,%10s,%10s,%10s,%10s,%10s,%5s,"
+TITLE_FORMAT+="%5s,%5s,%5s" # time
+TITLE_FORMAT+="\n"
+
+DATA_FORMAT="%40s,%25s,%30s,%7s,%9s,%8s,"
+DATA_FORMAT+="%10s,%13.0f,%14s,%11s,%12s,"
+DATA_FORMAT+="%7s,%11s,"
+DATA_FORMAT+="%9.0f,%10.0f,%10.0f,%10.0f,%10.0f,%10.0f,%5.0f,"
+DATA_FORMAT+="%5.0f,%5.0f,%5.0f" # time
+DATA_FORMAT+="\n"
+
+MAIN_PATTERN="$1""[[:blank:]]+:.*[[:blank:]]+([0-9\.]+)[[:blank:]]+ops/sec"
+PERC_PATTERN="Percentiles: P50: ([0-9\.]+) P75: ([0-9\.]+) "
+PERC_PATTERN+="P99: ([0-9\.]+) P99.9: ([0-9\.]+) P99.99: ([0-9\.]+)"
+#==============================================================================
+
+function main {
+  TEST_ROOT_DIR=${TEST_PATH:-"/tmp/rocksdb/regression_test"}
+  init_arguments $TEST_ROOT_DIR
+
+  build_db_bench_and_ldb
+
+  setup_test_directory
+  if [ $TEST_MODE -le 1 ]; then
+      tmp=$DB_PATH
+      DB_PATH=$ORIGIN_PATH
+      test_remote "test -d $DB_PATH"
+      if [[ $? -ne 0 ]]; then
+          echo "Building DB..."
+          # compactall alone will not print ops or threads, which will fail update_report
+          run_db_bench "fillseq,compactall" $NUM_KEYS 1 0 0
+      fi
+      DB_PATH=$tmp
+  fi
+  if [ $TEST_MODE -ge 1 ]; then
+      build_checkpoint
+      run_db_bench "readrandom"
+      run_db_bench "readwhilewriting"
+      run_db_bench "deleterandom" $((NUM_KEYS / 10 / $NUM_THREADS))
+      run_db_bench "seekrandom"
+      run_db_bench "seekrandomwhilewriting"
+  fi
+
+  cleanup_test_directory $TEST_ROOT_DIR
+  echo ""
+  echo "Benchmark completed!  Results are available in $RESULT_PATH"
+}
+
+############################################################################
+function init_arguments {
+  K=1024
+  M=$((1024 * K))
+  G=$((1024 * M))
+
+  current_time=$(date +"%F-%H:%M:%S")
+  RESULT_PATH=${RESULT_PATH:-"$1/results/$current_time"}
+  COMMIT_ID=`git log | head -n1 | cut -c 8-`
+  SUMMARY_FILE="$RESULT_PATH/SUMMARY.csv"
+
+  DB_PATH=${3:-"$1/db"}
+  ORIGIN_PATH=${ORIGIN_PATH:-"$(dirname $(dirname $DB_PATH))/db"}
+  WAL_PATH=${4:-""}
+  if [ -z "$REMOTE_USER_AT_HOST" ]; then
+    DB_BENCH_DIR=${5:-"."}
+  else
+    DB_BENCH_DIR=${5:-"$1/db_bench"}
+  fi
+
+  DEBUG=${DEBUG:-0}
+  TEST_MODE=${TEST_MODE:-1}
+  SCP=${SCP:-"scp"}
+  SSH=${SSH:-"ssh"}
+  NUM_THREADS=${NUM_THREADS:-16}
+  NUM_KEYS=${NUM_KEYS:-$((1 * G))}  # key range
+  NUM_OPS=${NUM_OPS:-$(($NUM_KEYS / $NUM_THREADS))}
+  KEY_SIZE=${KEY_SIZE:-100}
+  VALUE_SIZE=${VALUE_SIZE:-900}
+  CACHE_SIZE=${CACHE_SIZE:-$((1 * G))}
+  STATISTICS=${STATISTICS:-0}
+  COMPRESSION_RATIO=${COMPRESSION_RATIO:-0.5}
+  HISTOGRAM=${HISTOGRAM:-1}
+  NUM_MULTI_DB=${NUM_MULTI_DB:-1}
+  STATS_PER_INTERVAL=${STATS_PER_INTERVAL:-1}
+  STATS_INTERVAL_SECONDS=${STATS_INTERVAL_SECONDS:-600}
+  MAX_BACKGROUND_FLUSHES=${MAX_BACKGROUND_FLUSHES:-4}
+  MAX_BACKGROUND_COMPACTIONS=${MAX_BACKGROUND_COMPACTIONS:-16}
+  NUM_HIGH_PRI_THREADS=${NUM_HIGH_PRI_THREADS:-4}
+  NUM_LOW_PRI_THREADS=${NUM_LOW_PRI_THREADS:-16}
+  DELETE_TEST_PATH=${DELETE_TEST_PATH:-0}
+  SEEK_NEXTS=${SEEK_NEXTS:-10}
+  SEED=${SEED:-$( date +%s )}
+}
+
+# $1 --- benchmark name
+# $2 --- number of operations.  Default: $NUM_KEYS
+# $3 --- number of threads.  Default $NUM_THREADS
+# $4 --- use_existing_db.  Default: 1
+# $5 --- update_report. Default: 1
+function run_db_bench {
+  # this will terminate all currently-running db_bench
+  find_db_bench_cmd="ps aux | grep db_bench | grep -v grep | grep -v aux | awk '{print \$2}'"
+
+  ops=${2:-$NUM_OPS}
+  threads=${3:-$NUM_THREADS}
+  USE_EXISTING_DB=${4:-1}
+  UPDATE_REPORT=${5:-1}
+  echo ""
+  echo "======================================================================="
+  echo "Benchmark $1"
+  echo "======================================================================="
+  echo ""
+  db_bench_error=0
+  options_file_arg=$(setup_options_file)
+  echo "$options_file_arg"
+  # use `which time` to avoid using bash's internal time command
+  db_bench_cmd="("'\$(which time)'" -p $DB_BENCH_DIR/db_bench \
+      --benchmarks=$1 --db=$DB_PATH --wal_dir=$WAL_PATH \
+      --use_existing_db=$USE_EXISTING_DB \
+      --disable_auto_compactions \
+      --threads=$threads \
+      --num=$NUM_KEYS \
+      --reads=$ops \
+      --writes=$ops \
+      --deletes=$ops \
+      --key_size=$KEY_SIZE \
+      --value_size=$VALUE_SIZE \
+      --cache_size=$CACHE_SIZE \
+      --statistics=$STATISTICS \
+      $options_file_arg \
+      --compression_ratio=$COMPRESSION_RATIO \
+      --histogram=$HISTOGRAM \
+      --seek_nexts=$SEEK_NEXTS \
+      --stats_per_interval=$STATS_PER_INTERVAL \
+      --stats_interval_seconds=$STATS_INTERVAL_SECONDS \
+      --max_background_flushes=$MAX_BACKGROUND_FLUSHES \
+      --num_multi_db=$NUM_MULTI_DB \
+      --max_background_compactions=$MAX_BACKGROUND_COMPACTIONS \
+      --num_high_pri_threads=$NUM_HIGH_PRI_THREADS \
+      --num_low_pri_threads=$NUM_LOW_PRI_THREADS \
+      --seed=$SEED) 2>&1"
+  ps_cmd="ps aux"
+  if ! [ -z "$REMOTE_USER_AT_HOST" ]; then
+    echo "Running benchmark remotely on $REMOTE_USER_AT_HOST"
+    db_bench_cmd="$SSH $REMOTE_USER_AT_HOST \"$db_bench_cmd\""
+    ps_cmd="$SSH $REMOTE_USER_AT_HOST $ps_cmd"
+  fi
+
+  ## make sure no db_bench is running
+  # The following statement is necessary make sure "eval $ps_cmd" will success.
+  # Otherwise, if we simply check whether "$(eval $ps_cmd | grep db_bench)" is
+  # successful or not, then it will always be false since grep will return
+  # non-zero status when there's no matching output.
+  ps_output="$(eval $ps_cmd)"
+  exit_on_error $? "$ps_cmd"
+
+  # perform the actual command to check whether db_bench is running
+  grep_output="$(eval $ps_cmd | grep db_bench | grep -v grep)"
+  if [ "$grep_output" != "" ]; then
+    echo "Stopped regression_test.sh as there're still db_bench processes running:"
+    echo $grep_output
+    echo "Clean up test directory"
+    cleanup_test_directory $TEST_ROOT_DIR
+    exit 2
+  fi
+
+  ## run the db_bench
+  cmd="($db_bench_cmd || db_bench_error=1) | tee -a $RESULT_PATH/$1"
+  exit_on_error $?
+  echo $cmd
+  eval $cmd
+  exit_on_error $db_bench_error
+  if [ $UPDATE_REPORT -ne 0 ]; then
+    update_report "$1" "$RESULT_PATH/$1" $ops $threads
+  fi
+}
+
+function build_checkpoint {
+    cmd_prefix=""
+    if ! [ -z "$REMOTE_USER_AT_HOST" ]; then
+        cmd_prefix="$SSH $REMOTE_USER_AT_HOST "
+    fi
+    if [ $NUM_MULTI_DB -gt 1 ]; then
+        dirs=$($cmd_prefix find $ORIGIN_PATH -type d -links 2)
+        for dir in $dirs; do
+            db_index=$(basename $dir)
+            echo "Building checkpoints: $ORIGIN_PATH/$db_index -> $DB_PATH/$db_index ..."
+            $cmd_prefix $DB_BENCH_DIR/ldb checkpoint --checkpoint_dir=$DB_PATH/$db_index \
+                        --db=$ORIGIN_PATH/$db_index 2>&1
+        done
+    else
+        # checkpoint cannot build in directory already exists
+        $cmd_prefix rm -rf $DB_PATH
+        echo "Building checkpoint: $ORIGIN_PATH -> $DB_PATH ..."
+        $cmd_prefix $DB_BENCH_DIR/ldb checkpoint --checkpoint_dir=$DB_PATH \
+                    --db=$ORIGIN_PATH 2>&1
+    fi
+}
+
+function multiply {
+  echo "$1 * $2" | bc
+}
+
+# $1 --- name of the benchmark
+# $2 --- the filename of the output log of db_bench
+function update_report {
+  main_result=`cat $2 | grep $1`
+  exit_on_error $?
+  perc_statement=`cat $2 | grep Percentile`
+  exit_on_error $?
+
+  # Obtain micros / op
+
+  [[ $main_result =~ $MAIN_PATTERN ]]
+  ops_per_s=${BASH_REMATCH[1]}
+
+  # Obtain percentile information
+  [[ $perc_statement =~ $PERC_PATTERN ]]
+  perc[0]=${BASH_REMATCH[1]}  # p50
+  perc[1]=${BASH_REMATCH[2]}  # p75
+  perc[2]=${BASH_REMATCH[3]}  # p99
+  perc[3]=${BASH_REMATCH[4]}  # p99.9
+  perc[4]=${BASH_REMATCH[5]}  # p99.99
+
+  # Parse the output of the time command
+  real_sec=`tail -3 $2 | grep real | awk '{print $2}'`
+  user_sec=`tail -3 $2 | grep user | awk '{print $2}'`
+  sys_sec=`tail -3 $2 | grep sys | awk '{print $2}'`
+
+  (printf "$DATA_FORMAT" \
+    $COMMIT_ID $1 $REMOTE_USER_AT_HOST $NUM_MULTI_DB $NUM_KEYS $KEY_SIZE $VALUE_SIZE \
+       $(multiply $COMPRESSION_RATIO 100) \
+       $3 $4 $CACHE_SIZE \
+       $MAX_BACKGROUND_FLUSHES $MAX_BACKGROUND_COMPACTIONS \
+       $ops_per_s \
+       $(multiply ${perc[0]} 1000) \
+       $(multiply ${perc[1]} 1000) \
+       $(multiply ${perc[2]} 1000) \
+       $(multiply ${perc[3]} 1000) \
+       $(multiply ${perc[4]} 1000) \
+       $DEBUG \
+       $real_sec \
+       $user_sec \
+       $sys_sec \
+       >> $SUMMARY_FILE)
+  exit_on_error $?
+}
+
+function exit_on_error {
+  if [ $1 -ne 0 ]; then
+    echo ""
+    echo "ERROR: Benchmark did not complete successfully."
+    if ! [ -z "$2" ]; then
+      echo "Failure command: $2"
+    fi
+    echo "Partial results are output to $RESULT_PATH"
+    echo "ERROR" >> $SUMMARY_FILE
+    exit $1
+  fi
+}
+
+function checkout_rocksdb {
+  echo "Checking out commit $1 ..."
+
+  git fetch --all
+  exit_on_error $?
+
+  git checkout $1
+  exit_on_error $?
+}
+
+function build_db_bench_and_ldb {
+  echo "Building db_bench & ldb ..."
+
+  make clean
+  exit_on_error $?
+
+  DEBUG_LEVEL=0 PORTABLE=1 make db_bench ldb -j32
+  exit_on_error $?
+}
+
+function run_remote {
+  test_remote "$1"
+  exit_on_error $? "$1"
+}
+
+function test_remote {
+  if ! [ -z "$REMOTE_USER_AT_HOST" ]; then
+      cmd="$SSH $REMOTE_USER_AT_HOST '$1'"
+  else
+      cmd="$1"
+  fi
+  eval "$cmd"
+}
+
+function run_local {
+  eval "$1"
+  exit_on_error $?
+}
+
+function setup_options_file {
+  if ! [ -z "$OPTIONS_FILE" ]; then
+    if ! [ -z "$REMOTE_USER_AT_HOST" ]; then
+      options_file="$DB_BENCH_DIR/OPTIONS_FILE"
+      run_local "$SCP $OPTIONS_FILE $REMOTE_USER_AT_HOST:$options_file"
+    else
+      options_file="$OPTIONS_FILE"
+    fi
+    echo "--options_file=$options_file"
+  fi
+  echo ""
+}
+
+function setup_test_directory {
+  echo "Deleting old regression test directories and creating new ones"
+
+  run_remote "rm -rf $DB_PATH"
+  run_remote "rm -rf $DB_BENCH_DIR"
+  run_local "rm -rf $RESULT_PATH"
+
+  if ! [ -z "$WAL_PATH" ]; then
+    run_remote "rm -rf $WAL_PATH"
+    run_remote "mkdir -p $WAL_PATH"
+  fi
+
+  run_remote "mkdir -p $DB_PATH"
+
+  run_remote "mkdir -p $DB_BENCH_DIR"
+  run_remote "ls -l $DB_BENCH_DIR"
+
+  if ! [ -z "$REMOTE_USER_AT_HOST" ]; then
+      run_local "$SCP ./db_bench $REMOTE_USER_AT_HOST:$DB_BENCH_DIR/db_bench"
+      run_local "$SCP ./ldb $REMOTE_USER_AT_HOST:$DB_BENCH_DIR/ldb"
+  fi
+
+  run_local "mkdir -p $RESULT_PATH"
+
+  (printf $TITLE_FORMAT \
+      "commit id" "benchmark" "user@host" "num-dbs" "key-range" "key-size" \
+      "value-size" "compress-rate" "ops-per-thread" "num-threads" "cache-size" \
+      "flushes" "compactions" \
+      "ops-per-s" "p50" "p75" "p99" "p99.9" "p99.99" "debug" \
+      "real-sec" "user-sec" "sys-sec" \
+      >> $SUMMARY_FILE)
+  exit_on_error $?
+}
+
+function cleanup_test_directory {
+
+  if [ $DELETE_TEST_PATH -ne 0 ]; then
+    echo "Clear old regression test directories and creating new ones"
+    run_remote "rm -rf $DB_PATH"
+    run_remote "rm -rf $WAL_PATH"
+    if ! [ -z "$REMOTE_USER_AT_HOST" ]; then
+      run_remote "rm -rf $DB_BENCH_DIR"
+    fi
+    run_remote "rm -rf $1"
+  else
+    echo "------------ DEBUG MODE ------------"
+    echo "DB  PATH: $DB_PATH"
+    echo "WAL PATH: $WAL_PATH"
+  fi
+}
+
+############################################################################
+
+# shellcheck disable=SC2068
+main $@
diff --git a/src/rocksdb/tools/report_lite_binary_size.sh b/src/rocksdb/tools/report_lite_binary_size.sh
new file mode 100755
index 00000000..232bb9bc
--- /dev/null
+++ b/src/rocksdb/tools/report_lite_binary_size.sh
@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+# Script to report lite build binary size for latest RocksDB commits.
+# Usage:
+#   ./report_lite_binary_size [num_recent_commits]
+
+num_recent_commits=${1:-10}
+
+echo "Computing RocksDB lite build binary size for the most recent $num_recent_commits commits."
+
+for ((i=0; i < num_recent_commits; i++))
+do
+  git checkout master~$i
+  commit_hash=$(git show -s --format=%H)
+  commit_time=$(git show -s --format=%ct)
+
+  # It would be nice to check if scuba already have a record for the commit,
+  # but sandcastle don't seems to have scuba CLI installed.
+
+  make clean
+  make OPT=-DROCKSDB_LITE static_lib
+
+  if make OPT=-DROCKSDB_LITE static_lib
+  then
+    build_succeeded='true'
+    strip librocksdb.a
+    binary_size=$(stat -c %s librocksdb.a)
+  else
+    build_succeeded='false'
+    binary_size=0
+  fi
+
+  current_time="\"time\": $(date +%s)"
+  commit_hash="\"hash\": \"$commit_hash\""
+  commit_time="\"commit_time\": $commit_time"
+  build_succeeded="\"build_succeeded\": \"$build_succeeded\""
+  binary_size="\"binary_size\": $binary_size"
+
+  scribe_log="{\"int\":{$current_time, $commit_time, $binary_size}, \"normal\":{$commit_hash, $build_succeeded}}"
+  echo "Logging to scribe: $scribe_log"
+  scribe_cat perfpipe_rocksdb_lite_build "$scribe_log"
+done
diff --git a/src/rocksdb/tools/rocksdb_dump_test.sh b/src/rocksdb/tools/rocksdb_dump_test.sh
new file mode 100755
index 00000000..8d9c7f52
--- /dev/null
+++ b/src/rocksdb/tools/rocksdb_dump_test.sh
@@ -0,0 +1,8 @@
+# shellcheck disable=SC2148
+TESTDIR=`mktemp -d ${TMPDIR:-/tmp}/rocksdb-dump-test.XXXXX`
+DUMPFILE="tools/sample-dump.dmp"
+
+# Verify that the sample dump file is undumpable and then redumpable.
+./rocksdb_undump --dump_location=$DUMPFILE --db_path=$TESTDIR/db
+./rocksdb_dump --anonymous --db_path=$TESTDIR/db --dump_location=$TESTDIR/dump
+cmp $DUMPFILE $TESTDIR/dump
diff --git a/src/rocksdb/tools/run_flash_bench.sh b/src/rocksdb/tools/run_flash_bench.sh
new file mode 100755
index 00000000..4d9d0d55
--- /dev/null
+++ b/src/rocksdb/tools/run_flash_bench.sh
@@ -0,0 +1,358 @@
+#!/usr/bin/env bash
+# REQUIRE: benchmark.sh exists in the current directory
+# After execution of this script, log files are generated in $output_dir.
+# report.txt provides a high level statistics
+
+# This should be run from the parent of the tools directory. The command line is:
+#   [$env_vars] tools/run_flash_bench.sh [list-of-threads]
+#
+# This runs a sequence of tests in the following sequence:
+#   step 1) load - bulkload, compact, fillseq, overwrite
+#   step 2) read-only for each number of threads
+#   step 3) read-write for each number of threads
+#   step 4) merge for each number of threads
+#
+# The list of threads is optional and when not set is equivalent to "24". 
+# Were list-of-threads specified as "1 2 4" then the tests in steps 2, 3 and
+# 4 above would be repeated for 1, 2 and 4 threads. The tests in step 1 are
+# only run for 1 thread.
+
+# Test output is written to $OUTPUT_DIR, currently /tmp/output. The performance
+# summary is in $OUTPUT_DIR/report.txt. There is one file in $OUTPUT_DIR per
+# test and the tests are listed below.
+#
+# The environment variables are also optional. The variables are:
+#
+#   NKEYS         - number of key/value pairs to load
+#   BG_MBWRITEPERSEC - write rate limit in MB/second for tests in which
+#                   there is one thread doing writes and stats are
+#                   reported for read threads. "BG" stands for background.
+#                   If this is too large then the non-writer threads can get
+#                   starved. This is used for the "readwhile" tests.
+#   FG_MBWRITEPERSEC - write rate limit in MB/second for tests like overwrite
+#                   where stats are reported for the write threads.
+#   NSECONDS      - number of seconds for which to run each test in steps 2,
+#                   3 and 4. There are currently 15 tests in those steps and
+#                   they are repeated for each entry in list-of-threads so
+#                   this variable lets you control the total duration to
+#                   finish the benchmark.
+#   RANGE_LIMIT   - the number of rows to read per range query for tests that
+#                   do range queries.
+#   VAL_SIZE      - the length of the value in the key/value pairs loaded.
+#                   You can estimate the size of the test database from this,
+#                   NKEYS and the compression rate (--compression_ratio) set
+#                   in tools/benchmark.sh
+#   BLOCK_LENGTH  - value for db_bench --block_size
+#   CACHE_BYTES   - the size of the RocksDB block cache in bytes
+#   DATA_DIR      - directory in which to create database files
+#   LOG_DIR       - directory in which to create WAL files, may be the same
+#                   as DATA_DIR
+#   DO_SETUP      - when set to 0 then a backup of the database is copied from
+#                   $DATA_DIR.bak to $DATA_DIR and the load tests from step 1
+#                   The WAL directory is also copied from a backup if
+#                   DATA_DIR != LOG_DIR. This allows tests from steps 2, 3, 4
+#                   to be repeated faster.
+#   SAVE_SETUP    - saves a copy of the database at the end of step 1 to
+#                   $DATA_DIR.bak. When LOG_DIR != DATA_DIR then it is copied
+#                   to $LOG_DIR.bak.
+#   SKIP_LOW_PRI_TESTS - skip some of the tests which aren't crucial for getting
+#                   actionable benchmarking data (look for keywords "bulkload",
+#                   "sync=1", and "while merging").
+#
+
+# Size constants
+K=1024
+M=$((1024 * K))
+G=$((1024 * M))
+
+num_keys=${NKEYS:-$((1 * G))}
+# write rate for readwhile... tests
+bg_mbwps=${BG_MBWRITEPERSEC:-4}
+# write rate for tests other than readwhile, 0 means no limit
+fg_mbwps=${FG_MBWRITEPERSEC:-0}
+duration=${NSECONDS:-$((60 * 60))}
+nps=${RANGE_LIMIT:-10}
+vs=${VAL_SIZE:-400}
+cs=${CACHE_BYTES:-$(( 1 * G ))}
+bs=${BLOCK_LENGTH:-8192}
+
+# If no command line arguments then run for 24 threads.
+if [[ $# -eq 0 ]]; then
+  nthreads=( 24 )
+else
+  nthreads=( "$@" )
+fi
+
+for num_thr in "${nthreads[@]}" ; do
+  echo Will run for $num_thr threads
+done
+
+# Update these parameters before execution !!!
+db_dir=${DATA_DIR:-"/tmp/rocksdb/"}
+wal_dir=${LOG_DIR:-"/tmp/rocksdb/"}
+
+do_setup=${DO_SETUP:-1}
+save_setup=${SAVE_SETUP:-0}
+
+# By default we'll run all the tests. Set this to skip a set of tests which
+# aren't critical for getting key metrics.
+skip_low_pri_tests=${SKIP_LOW_PRI_TESTS:-0}
+
+if [[ $skip_low_pri_tests == 1 ]]; then
+  echo "Skipping some non-critical tests because SKIP_LOW_PRI_TESTS is set."
+fi
+
+output_dir="${TMPDIR:-/tmp}/output"
+
+ARGS="\
+OUTPUT_DIR=$output_dir \
+NUM_KEYS=$num_keys \
+DB_DIR=$db_dir \
+WAL_DIR=$wal_dir \
+VALUE_SIZE=$vs \
+BLOCK_SIZE=$bs \
+CACHE_SIZE=$cs"
+
+mkdir -p $output_dir
+echo -e "ops/sec\tmb/sec\tSize-GB\tL0_GB\tSum_GB\tW-Amp\tW-MB/s\tusec/op\tp50\tp75\tp99\tp99.9\tp99.99\tUptime\tStall-time\tStall%\tTest" \
+  > $output_dir/report.txt
+
+# Notes on test sequence:
+#   step 1) Setup database via sequential fill followed by overwrite to fragment it.
+#           Done without setting DURATION to make sure that overwrite does $num_keys writes
+#   step 2) read-only tests for all levels of concurrency requested
+#   step 3) non read-only tests for all levels of concurrency requested
+#   step 4) merge tests for all levels of concurrency requested. These must come last.
+
+###### Setup the database
+
+if [[ $do_setup != 0 ]]; then
+  echo Doing setup
+
+  if [[ $skip_low_pri_tests != 1 ]]; then
+    # Test 1: bulk load
+    env $ARGS ./tools/benchmark.sh bulkload
+  fi
+
+  # Test 2a: sequential fill with large values to get peak ingest
+  #          adjust NUM_KEYS given the use of larger values
+  env $ARGS BLOCK_SIZE=$((1 * M)) VALUE_SIZE=$((32 * K)) NUM_KEYS=$(( num_keys / 64 )) \
+       ./tools/benchmark.sh fillseq_disable_wal
+
+  # Test 2b: sequential fill with the configured value size
+  env $ARGS ./tools/benchmark.sh fillseq_disable_wal
+
+  # Test 2c: same as 2a, but with WAL being enabled.
+  env $ARGS BLOCK_SIZE=$((1 * M)) VALUE_SIZE=$((32 * K)) NUM_KEYS=$(( num_keys / 64 )) \
+       ./tools/benchmark.sh fillseq_enable_wal
+
+  # Test 2d: same as 2b, but with WAL being enabled.
+  env $ARGS ./tools/benchmark.sh fillseq_enable_wal
+
+  # Test 3: single-threaded overwrite
+  env $ARGS NUM_THREADS=1 DB_BENCH_NO_SYNC=1 ./tools/benchmark.sh overwrite
+
+else
+  echo Restoring from backup
+
+  rm -rf $db_dir
+
+  if [ ! -d ${db_dir}.bak ]; then
+    echo Database backup does not exist at ${db_dir}.bak
+    exit -1
+  fi
+
+  echo Restore database from ${db_dir}.bak
+  cp -p -r ${db_dir}.bak $db_dir
+
+  if [[ $db_dir != $wal_dir ]]; then
+    rm -rf $wal_dir
+
+    if [ ! -d ${wal_dir}.bak ]; then
+      echo WAL backup does not exist at ${wal_dir}.bak
+      exit -1
+    fi
+
+    echo Restore WAL from ${wal_dir}.bak
+    cp -p -r ${wal_dir}.bak $wal_dir
+  fi
+fi
+
+if [[ $save_setup != 0 ]]; then
+  echo Save database to ${db_dir}.bak
+  cp -p -r $db_dir ${db_dir}.bak
+
+  if [[ $db_dir != $wal_dir ]]; then
+    echo Save WAL to ${wal_dir}.bak
+    cp -p -r $wal_dir ${wal_dir}.bak
+  fi
+fi
+
+###### Read-only tests
+
+for num_thr in "${nthreads[@]}" ; do
+  # Test 4: random read
+  env $ARGS DURATION=$duration NUM_THREADS=$num_thr ./tools/benchmark.sh readrandom
+
+  # Test 5: random range scans
+  env $ARGS DURATION=$duration NUM_THREADS=$num_thr NUM_NEXTS_PER_SEEK=$nps \
+    ./tools/benchmark.sh fwdrange
+
+  # Test 6: random reverse range scans
+  env $ARGS DURATION=$duration NUM_THREADS=$num_thr NUM_NEXTS_PER_SEEK=$nps \
+    ./tools/benchmark.sh revrange
+done
+
+###### Non read-only tests
+
+for num_thr in "${nthreads[@]}" ; do
+  # Test 7: overwrite with sync=0
+  env $ARGS DURATION=$duration NUM_THREADS=$num_thr MB_WRITE_PER_SEC=$fg_mbwps \
+    DB_BENCH_NO_SYNC=1 ./tools/benchmark.sh overwrite
+
+  if [[ $skip_low_pri_tests != 1 ]]; then
+    # Test 8: overwrite with sync=1
+    env $ARGS DURATION=$duration NUM_THREADS=$num_thr MB_WRITE_PER_SEC=$fg_mbwps \
+      ./tools/benchmark.sh overwrite
+  fi
+
+  # Test 9: random update with sync=0
+  env $ARGS DURATION=$duration NUM_THREADS=$num_thr DB_BENCH_NO_SYNC=1 \
+      ./tools/benchmark.sh updaterandom
+
+  if [[ $skip_low_pri_tests != 1 ]]; then
+    # Test 10: random update with sync=1
+   env $ARGS DURATION=$duration NUM_THREADS=$num_thr ./tools/benchmark.sh updaterandom
+  fi
+
+  # Test 11: random read while writing
+  env $ARGS DURATION=$duration NUM_THREADS=$num_thr MB_WRITE_PER_SEC=$bg_mbwps \
+    DB_BENCH_NO_SYNC=1 ./tools/benchmark.sh readwhilewriting
+
+  # Test 12: range scan while writing
+  env $ARGS DURATION=$duration NUM_THREADS=$num_thr MB_WRITE_PER_SEC=$bg_mbwps \
+    DB_BENCH_NO_SYNC=1 NUM_NEXTS_PER_SEEK=$nps ./tools/benchmark.sh fwdrangewhilewriting
+
+  # Test 13: reverse range scan while writing
+  env $ARGS DURATION=$duration NUM_THREADS=$num_thr MB_WRITE_PER_SEC=$bg_mbwps \
+    DB_BENCH_NO_SYNC=1 NUM_NEXTS_PER_SEEK=$nps ./tools/benchmark.sh revrangewhilewriting
+done
+
+###### Merge tests
+
+for num_thr in "${nthreads[@]}" ; do
+  # Test 14: random merge with sync=0
+  env $ARGS DURATION=$duration NUM_THREADS=$num_thr MB_WRITE_PER_SEC=$fg_mbwps \
+    DB_BENCH_NO_SYNC=1 ./tools/benchmark.sh mergerandom
+
+  if [[ $skip_low_pri_tests != 1 ]]; then
+    # Test 15: random merge with sync=1
+    env $ARGS DURATION=$duration NUM_THREADS=$num_thr MB_WRITE_PER_SEC=$fg_mbwps \
+      ./tools/benchmark.sh mergerandom
+
+    # Test 16: random read while merging 
+    env $ARGS DURATION=$duration NUM_THREADS=$num_thr MB_WRITE_PER_SEC=$bg_mbwps \
+      DB_BENCH_NO_SYNC=1 ./tools/benchmark.sh readwhilemerging
+
+    # Test 17: range scan while merging 
+    env $ARGS DURATION=$duration NUM_THREADS=$num_thr MB_WRITE_PER_SEC=$bg_mbwps \
+      DB_BENCH_NO_SYNC=1 NUM_NEXTS_PER_SEEK=$nps ./tools/benchmark.sh fwdrangewhilemerging
+
+    # Test 18: reverse range scan while merging 
+    env $ARGS DURATION=$duration NUM_THREADS=$num_thr MB_WRITE_PER_SEC=$bg_mbwps \
+      DB_BENCH_NO_SYNC=1 NUM_NEXTS_PER_SEEK=$nps ./tools/benchmark.sh revrangewhilemerging
+  fi
+done
+
+###### Universal compaction tests.
+
+# Use a single thread to reduce the variability in the benchmark.
+env $ARGS COMPACTION_TEST=1 NUM_THREADS=1 ./tools/benchmark.sh universal_compaction
+
+if [[ $skip_low_pri_tests != 1 ]]; then
+  echo bulkload > $output_dir/report2.txt
+  head -1 $output_dir/report.txt >> $output_dir/report2.txt
+  grep bulkload $output_dir/report.txt >> $output_dir/report2.txt
+fi
+
+echo fillseq_wal_disabled >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep fillseq.wal_disabled $output_dir/report.txt >> $output_dir/report2.txt
+
+echo fillseq_wal_enabled >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep fillseq.wal_enabled $output_dir/report.txt >> $output_dir/report2.txt
+
+echo overwrite sync=0 >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep overwrite $output_dir/report.txt | grep \.s0  >> $output_dir/report2.txt
+
+if [[ $skip_low_pri_tests != 1 ]]; then
+  echo overwrite sync=1 >> $output_dir/report2.txt
+  head -1 $output_dir/report.txt >> $output_dir/report2.txt
+  grep overwrite $output_dir/report.txt | grep \.s1  >> $output_dir/report2.txt
+fi
+
+echo updaterandom sync=0 >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep updaterandom $output_dir/report.txt | grep \.s0 >> $output_dir/report2.txt
+
+if [[ $skip_low_pri_tests != 1 ]]; then
+  echo updaterandom sync=1 >> $output_dir/report2.txt
+  head -1 $output_dir/report.txt >> $output_dir/report2.txt
+  grep updaterandom $output_dir/report.txt | grep \.s1 >> $output_dir/report2.txt
+fi
+
+echo mergerandom sync=0 >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep mergerandom $output_dir/report.txt | grep \.s0 >> $output_dir/report2.txt
+
+if [[ $skip_low_pri_tests != 1 ]]; then
+  echo mergerandom sync=1 >> $output_dir/report2.txt
+  head -1 $output_dir/report.txt >> $output_dir/report2.txt
+  grep mergerandom $output_dir/report.txt | grep \.s1 >> $output_dir/report2.txt
+fi
+
+echo readrandom >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep readrandom $output_dir/report.txt  >> $output_dir/report2.txt
+
+echo fwdrange >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep fwdrange\.t $output_dir/report.txt >> $output_dir/report2.txt
+
+echo revrange >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep revrange\.t $output_dir/report.txt >> $output_dir/report2.txt
+
+echo readwhile >> $output_dir/report2.txt >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep readwhilewriting $output_dir/report.txt >> $output_dir/report2.txt
+
+if [[ $skip_low_pri_tests != 1 ]]; then
+  echo readwhile >> $output_dir/report2.txt
+  head -1 $output_dir/report.txt >> $output_dir/report2.txt
+  grep readwhilemerging $output_dir/report.txt >> $output_dir/report2.txt
+fi
+
+echo fwdreadwhilewriting >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep fwdrangewhilewriting $output_dir/report.txt >> $output_dir/report2.txt
+
+if [[ $skip_low_pri_tests != 1 ]]; then
+  echo fwdreadwhilemerging >> $output_dir/report2.txt
+  head -1 $output_dir/report.txt >> $output_dir/report2.txt
+  grep fwdrangewhilemerg $output_dir/report.txt >> $output_dir/report2.txt
+fi
+
+echo revreadwhilewriting >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep revrangewhilewriting $output_dir/report.txt >> $output_dir/report2.txt
+
+if [[ $skip_low_pri_tests != 1 ]]; then
+  echo revreadwhilemerging >> $output_dir/report2.txt
+  head -1 $output_dir/report.txt >> $output_dir/report2.txt
+  grep revrangewhilemerg $output_dir/report.txt >> $output_dir/report2.txt
+fi
+
+cat $output_dir/report2.txt
diff --git a/src/rocksdb/tools/run_leveldb.sh b/src/rocksdb/tools/run_leveldb.sh
new file mode 100755
index 00000000..de628c31
--- /dev/null
+++ b/src/rocksdb/tools/run_leveldb.sh
@@ -0,0 +1,174 @@
+#!/usr/bin/env bash
+# REQUIRE: benchmark_leveldb.sh exists in the current directory
+# After execution of this script, log files are generated in $output_dir.
+# report.txt provides a high level statistics
+#
+# This should be used with the LevelDB fork listed here to use additional test options.
+# For more details on the changes see the blog post listed below.
+#   https://github.com/mdcallag/leveldb-1
+#   http://smalldatum.blogspot.com/2015/04/comparing-leveldb-and-rocksdb-take-2.html
+#
+# This should be run from the parent of the tools directory. The command line is:
+#   [$env_vars] tools/run_flash_bench.sh [list-of-threads]
+#
+# This runs a sequence of tests in the following sequence:
+#   step 1) load - bulkload, compact, fillseq, overwrite
+#   step 2) read-only for each number of threads
+#   step 3) read-write for each number of threads
+#
+# The list of threads is optional and when not set is equivalent to "24". 
+# Were list-of-threads specified as "1 2 4" then the tests in steps 2, 3 and
+# 4 above would be repeated for 1, 2 and 4 threads. The tests in step 1 are
+# only run for 1 thread.
+
+# Test output is written to $OUTPUT_DIR, currently /tmp/output. The performance
+# summary is in $OUTPUT_DIR/report.txt. There is one file in $OUTPUT_DIR per
+# test and the tests are listed below.
+#
+# The environment variables are also optional. The variables are:
+#   NKEYS         - number of key/value pairs to load
+#   NWRITESPERSEC - the writes/second rate limit for the *whilewriting* tests.
+#                   If this is too large then the non-writer threads can get
+#                   starved.
+#   VAL_SIZE      - the length of the value in the key/value pairs loaded.
+#                   You can estimate the size of the test database from this,
+#                   NKEYS and the compression rate (--compression_ratio) set
+#                   in tools/benchmark_leveldb.sh
+#   BLOCK_LENGTH  - value for db_bench --block_size
+#   CACHE_BYTES   - the size of the RocksDB block cache in bytes
+#   DATA_DIR      - directory in which to create database files
+#   DO_SETUP      - when set to 0 then a backup of the database is copied from
+#                   $DATA_DIR.bak to $DATA_DIR and the load tests from step 1
+#                   This allows tests from steps 2, 3 to be repeated faster.
+#   SAVE_SETUP    - saves a copy of the database at the end of step 1 to
+#                   $DATA_DIR.bak.
+
+# Size constants
+K=1024
+M=$((1024 * K))
+G=$((1024 * M))
+
+num_keys=${NKEYS:-$((1 * G))}
+wps=${NWRITESPERSEC:-$((10 * K))}
+vs=${VAL_SIZE:-400}
+cs=${CACHE_BYTES:-$(( 1 * G ))}
+bs=${BLOCK_LENGTH:-4096}
+
+# If no command line arguments then run for 24 threads.
+if [[ $# -eq 0 ]]; then
+  nthreads=( 24 )
+else
+  nthreads=( "$@" )
+fi
+
+for num_thr in "${nthreads[@]}" ; do
+  echo Will run for $num_thr threads
+done
+
+# Update these parameters before execution !!!
+db_dir=${DATA_DIR:-"/tmp/rocksdb/"}
+
+do_setup=${DO_SETUP:-1}
+save_setup=${SAVE_SETUP:-0}
+
+output_dir="${TMPDIR:-/tmp}/output"
+
+ARGS="\
+OUTPUT_DIR=$output_dir \
+NUM_KEYS=$num_keys \
+DB_DIR=$db_dir \
+VALUE_SIZE=$vs \
+BLOCK_SIZE=$bs \
+CACHE_SIZE=$cs"
+
+mkdir -p $output_dir
+echo -e "ops/sec\tmb/sec\tusec/op\tavg\tp50\tTest" \
+  > $output_dir/report.txt
+
+# Notes on test sequence:
+#   step 1) Setup database via sequential fill followed by overwrite to fragment it.
+#           Done without setting DURATION to make sure that overwrite does $num_keys writes
+#   step 2) read-only tests for all levels of concurrency requested
+#   step 3) non read-only tests for all levels of concurrency requested
+
+###### Setup the database
+
+if [[ $do_setup != 0 ]]; then
+  echo Doing setup
+
+  # Test 2a: sequential fill with large values to get peak ingest
+  #          adjust NUM_KEYS given the use of larger values
+  env $ARGS BLOCK_SIZE=$((1 * M)) VALUE_SIZE=$((32 * K)) NUM_KEYS=$(( num_keys / 64 )) \
+       ./tools/benchmark_leveldb.sh fillseq
+
+  # Test 2b: sequential fill with the configured value size
+  env $ARGS ./tools/benchmark_leveldb.sh fillseq
+
+  # Test 3: single-threaded overwrite
+  env $ARGS NUM_THREADS=1 DB_BENCH_NO_SYNC=1 ./tools/benchmark_leveldb.sh overwrite
+
+else
+  echo Restoring from backup
+
+  rm -rf $db_dir
+
+  if [ ! -d ${db_dir}.bak ]; then
+    echo Database backup does not exist at ${db_dir}.bak
+    exit -1
+  fi
+
+  echo Restore database from ${db_dir}.bak
+  cp -p -r ${db_dir}.bak $db_dir
+fi
+
+if [[ $save_setup != 0 ]]; then
+  echo Save database to ${db_dir}.bak
+  cp -p -r $db_dir ${db_dir}.bak
+fi
+
+###### Read-only tests
+
+for num_thr in "${nthreads[@]}" ; do
+  # Test 4: random read
+  env $ARGS NUM_THREADS=$num_thr ./tools/benchmark_leveldb.sh readrandom
+
+done
+
+###### Non read-only tests
+
+for num_thr in "${nthreads[@]}" ; do
+  # Test 7: overwrite with sync=0
+  env $ARGS NUM_THREADS=$num_thr DB_BENCH_NO_SYNC=1 \
+    ./tools/benchmark_leveldb.sh overwrite
+
+  # Test 8: overwrite with sync=1
+  # Not run for now because LevelDB db_bench doesn't have an option to limit the
+  # test run to X seconds and doing sync-per-commit for --num can take too long.
+  # env $ARGS NUM_THREADS=$num_thr ./tools/benchmark_leveldb.sh overwrite
+
+  # Test 11: random read while writing
+  env $ARGS NUM_THREADS=$num_thr WRITES_PER_SECOND=$wps \
+    ./tools/benchmark_leveldb.sh readwhilewriting
+
+done
+
+echo bulkload > $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep bulkload $output_dir/report.txt >> $output_dir/report2.txt
+echo fillseq >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep fillseq $output_dir/report.txt >> $output_dir/report2.txt
+echo overwrite sync=0 >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep overwrite $output_dir/report.txt | grep \.s0  >> $output_dir/report2.txt
+echo overwrite sync=1 >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep overwrite $output_dir/report.txt | grep \.s1  >> $output_dir/report2.txt
+echo readrandom >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep readrandom $output_dir/report.txt  >> $output_dir/report2.txt
+echo readwhile >> $output_dir/report2.txt >> $output_dir/report2.txt
+head -1 $output_dir/report.txt >> $output_dir/report2.txt
+grep readwhilewriting $output_dir/report.txt >> $output_dir/report2.txt
+
+cat $output_dir/report2.txt
diff --git a/src/rocksdb/tools/sample-dump.dmp b/src/rocksdb/tools/sample-dump.dmp
new file mode 100644
index 00000000..4ec3a773
--- /dev/null
+++ b/src/rocksdb/tools/sample-dump.dmp
diff --git a/src/rocksdb/tools/sst_dump.cc b/src/rocksdb/tools/sst_dump.cc
new file mode 100644
index 00000000..4e10a8c0
--- /dev/null
+++ b/src/rocksdb/tools/sst_dump.cc
@@ -0,0 +1,21 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+#ifndef ROCKSDB_LITE
+
+#include "rocksdb/sst_dump_tool.h"
+
+int main(int argc, char** argv) {
+  rocksdb::SSTDumpTool tool;
+  tool.Run(argc, argv);
+  return 0;
+}
+#else
+#include <stdio.h>
+int main(int /*argc*/, char** /*argv*/) {
+  fprintf(stderr, "Not supported in lite mode.\n");
+  return 1;
+}
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/sst_dump_test.cc b/src/rocksdb/tools/sst_dump_test.cc
new file mode 100644
index 00000000..6bf3e3b9
--- /dev/null
+++ b/src/rocksdb/tools/sst_dump_test.cc
@@ -0,0 +1,244 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#ifndef ROCKSDB_LITE
+
+#include <stdint.h>
+#include "rocksdb/sst_dump_tool.h"
+
+#include "rocksdb/filter_policy.h"
+#include "table/block_based_table_factory.h"
+#include "table/table_builder.h"
+#include "util/file_reader_writer.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+
+namespace rocksdb {
+
+const uint32_t optLength = 100;
+
+namespace {
+static std::string MakeKey(int i) {
+  char buf[100];
+  snprintf(buf, sizeof(buf), "k_%04d", i);
+  InternalKey key(std::string(buf), 0, ValueType::kTypeValue);
+  return key.Encode().ToString();
+}
+
+static std::string MakeValue(int i) {
+  char buf[100];
+  snprintf(buf, sizeof(buf), "v_%04d", i);
+  InternalKey key(std::string(buf), 0, ValueType::kTypeValue);
+  return key.Encode().ToString();
+}
+
+void createSST(const Options& opts, const std::string& file_name) {
+  Env* env = opts.env;
+  EnvOptions env_options(opts);
+  ReadOptions read_options;
+  const ImmutableCFOptions imoptions(opts);
+  const MutableCFOptions moptions(opts);
+  rocksdb::InternalKeyComparator ikc(opts.comparator);
+  std::unique_ptr<TableBuilder> tb;
+
+  std::unique_ptr<WritableFile> file;
+  ASSERT_OK(env->NewWritableFile(file_name, &file, env_options));
+
+  std::vector<std::unique_ptr<IntTblPropCollectorFactory> >
+      int_tbl_prop_collector_factories;
+  std::unique_ptr<WritableFileWriter> file_writer(
+      new WritableFileWriter(std::move(file), file_name, EnvOptions()));
+  std::string column_family_name;
+  int unknown_level = -1;
+  tb.reset(opts.table_factory->NewTableBuilder(
+      TableBuilderOptions(
+          imoptions, moptions, ikc, &int_tbl_prop_collector_factories,
+          CompressionType::kNoCompression, 0 /* sample_for_compression */,
+          CompressionOptions(), false /* skip_filters */, column_family_name,
+          unknown_level),
+      TablePropertiesCollectorFactory::Context::kUnknownColumnFamily,
+      file_writer.get()));
+
+  // Populate slightly more than 1K keys
+  uint32_t num_keys = 1024;
+  for (uint32_t i = 0; i < num_keys; i++) {
+    tb->Add(MakeKey(i), MakeValue(i));
+  }
+  tb->Finish();
+  file_writer->Close();
+}
+
+void cleanup(const Options& opts, const std::string& file_name) {
+  Env* env = opts.env;
+  env->DeleteFile(file_name);
+  std::string outfile_name = file_name.substr(0, file_name.length() - 4);
+  outfile_name.append("_dump.txt");
+  env->DeleteFile(outfile_name);
+}
+}  // namespace
+
+// Test for sst dump tool "raw" mode
+class SSTDumpToolTest : public testing::Test {
+  std::string testDir_;
+
+ public:
+  SSTDumpToolTest() { testDir_ = test::TmpDir(); }
+
+  ~SSTDumpToolTest() override {}
+
+  std::string MakeFilePath(const std::string& file_name) const {
+    std::string path(testDir_);
+    path.append("/").append(file_name);
+    return path;
+  }
+
+  template <std::size_t N>
+  void PopulateCommandArgs(const std::string& file_path, const char* command,
+                           char* (&usage)[N]) const {
+    for (int i = 0; i < static_cast<int>(N); ++i) {
+      usage[i] = new char[optLength];
+    }
+    snprintf(usage[0], optLength, "./sst_dump");
+    snprintf(usage[1], optLength, "%s", command);
+    snprintf(usage[2], optLength, "--file=%s", file_path.c_str());
+  }
+};
+
+TEST_F(SSTDumpToolTest, EmptyFilter) {
+  Options opts;
+  std::string file_path = MakeFilePath("rocksdb_sst_test.sst");
+  createSST(opts, file_path);
+
+  char* usage[3];
+  PopulateCommandArgs(file_path, "--command=raw", usage);
+
+  rocksdb::SSTDumpTool tool;
+  ASSERT_TRUE(!tool.Run(3, usage, opts));
+
+  cleanup(opts, file_path);
+  for (int i = 0; i < 3; i++) {
+    delete[] usage[i];
+  }
+}
+
+TEST_F(SSTDumpToolTest, FilterBlock) {
+  Options opts;
+  BlockBasedTableOptions table_opts;
+  table_opts.filter_policy.reset(rocksdb::NewBloomFilterPolicy(10, true));
+  opts.table_factory.reset(new BlockBasedTableFactory(table_opts));
+  std::string file_path = MakeFilePath("rocksdb_sst_test.sst");
+  createSST(opts, file_path);
+
+  char* usage[3];
+  PopulateCommandArgs(file_path, "--command=raw", usage);
+
+  rocksdb::SSTDumpTool tool;
+  ASSERT_TRUE(!tool.Run(3, usage, opts));
+
+  cleanup(opts, file_path);
+  for (int i = 0; i < 3; i++) {
+    delete[] usage[i];
+  }
+}
+
+TEST_F(SSTDumpToolTest, FullFilterBlock) {
+  Options opts;
+  BlockBasedTableOptions table_opts;
+  table_opts.filter_policy.reset(rocksdb::NewBloomFilterPolicy(10, false));
+  opts.table_factory.reset(new BlockBasedTableFactory(table_opts));
+  std::string file_path = MakeFilePath("rocksdb_sst_test.sst");
+  createSST(opts, file_path);
+
+  char* usage[3];
+  PopulateCommandArgs(file_path, "--command=raw", usage);
+
+  rocksdb::SSTDumpTool tool;
+  ASSERT_TRUE(!tool.Run(3, usage, opts));
+
+  cleanup(opts, file_path);
+  for (int i = 0; i < 3; i++) {
+    delete[] usage[i];
+  }
+}
+
+TEST_F(SSTDumpToolTest, GetProperties) {
+  Options opts;
+  BlockBasedTableOptions table_opts;
+  table_opts.filter_policy.reset(rocksdb::NewBloomFilterPolicy(10, false));
+  opts.table_factory.reset(new BlockBasedTableFactory(table_opts));
+  std::string file_path = MakeFilePath("rocksdb_sst_test.sst");
+  createSST(opts, file_path);
+
+  char* usage[3];
+  PopulateCommandArgs(file_path, "--show_properties", usage);
+
+  rocksdb::SSTDumpTool tool;
+  ASSERT_TRUE(!tool.Run(3, usage, opts));
+
+  cleanup(opts, file_path);
+  for (int i = 0; i < 3; i++) {
+    delete[] usage[i];
+  }
+}
+
+TEST_F(SSTDumpToolTest, CompressedSizes) {
+  Options opts;
+  BlockBasedTableOptions table_opts;
+  table_opts.filter_policy.reset(rocksdb::NewBloomFilterPolicy(10, false));
+  opts.table_factory.reset(new BlockBasedTableFactory(table_opts));
+  std::string file_path = MakeFilePath("rocksdb_sst_test.sst");
+  createSST(opts, file_path);
+
+  char* usage[3];
+  PopulateCommandArgs(file_path, "--command=recompress", usage);
+
+  rocksdb::SSTDumpTool tool;
+  ASSERT_TRUE(!tool.Run(3, usage, opts));
+
+  cleanup(opts, file_path);
+  for (int i = 0; i < 3; i++) {
+    delete[] usage[i];
+  }
+}
+
+TEST_F(SSTDumpToolTest, MemEnv) {
+  std::unique_ptr<Env> env(NewMemEnv(Env::Default()));
+  Options opts;
+  opts.env = env.get();
+  std::string file_path = MakeFilePath("rocksdb_sst_test.sst");
+  createSST(opts, file_path);
+
+  char* usage[3];
+  PopulateCommandArgs(file_path, "--command=verify_checksum", usage);
+
+  rocksdb::SSTDumpTool tool;
+  ASSERT_TRUE(!tool.Run(3, usage, opts));
+
+  cleanup(opts, file_path);
+  for (int i = 0; i < 3; i++) {
+    delete[] usage[i];
+  }
+}
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
+
+#else
+#include <stdio.h>
+
+int main(int /*argc*/, char** /*argv*/) {
+  fprintf(stderr, "SKIPPED as SSTDumpTool is not supported in ROCKSDB_LITE\n");
+  return 0;
+}
+
+#endif  // !ROCKSDB_LITE  return RUN_ALL_TESTS();
diff --git a/src/rocksdb/tools/sst_dump_tool.cc b/src/rocksdb/tools/sst_dump_tool.cc
new file mode 100644
index 00000000..5cbbfc38
--- /dev/null
+++ b/src/rocksdb/tools/sst_dump_tool.cc
@@ -0,0 +1,686 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+#ifndef ROCKSDB_LITE
+
+#include "tools/sst_dump_tool_imp.h"
+
+#ifndef __STDC_FORMAT_MACROS
+#define __STDC_FORMAT_MACROS
+#endif
+
+#include <inttypes.h>
+#include <iostream>
+#include <map>
+#include <memory>
+#include <sstream>
+#include <vector>
+
+#include "db/memtable.h"
+#include "db/write_batch_internal.h"
+#include "options/cf_options.h"
+#include "rocksdb/db.h"
+#include "rocksdb/env.h"
+#include "rocksdb/iterator.h"
+#include "rocksdb/slice_transform.h"
+#include "rocksdb/status.h"
+#include "rocksdb/table_properties.h"
+#include "rocksdb/utilities/ldb_cmd.h"
+#include "table/block.h"
+#include "table/block_based_table_builder.h"
+#include "table/block_based_table_factory.h"
+#include "table/block_builder.h"
+#include "table/format.h"
+#include "table/meta_blocks.h"
+#include "table/plain_table_factory.h"
+#include "table/table_reader.h"
+#include "util/compression.h"
+#include "util/random.h"
+
+#include "port/port.h"
+
+namespace rocksdb {
+
+SstFileDumper::SstFileDumper(const Options& options,
+                             const std::string& file_path, bool verify_checksum,
+                             bool output_hex)
+    : file_name_(file_path),
+      read_num_(0),
+      verify_checksum_(verify_checksum),
+      output_hex_(output_hex),
+      options_(options),
+      ioptions_(options_),
+      moptions_(ColumnFamilyOptions(options_)),
+      internal_comparator_(BytewiseComparator()) {
+  fprintf(stdout, "Process %s\n", file_path.c_str());
+  init_result_ = GetTableReader(file_name_);
+}
+
+extern const uint64_t kBlockBasedTableMagicNumber;
+extern const uint64_t kLegacyBlockBasedTableMagicNumber;
+extern const uint64_t kPlainTableMagicNumber;
+extern const uint64_t kLegacyPlainTableMagicNumber;
+
+const char* testFileName = "test_file_name";
+
+static const std::vector<std::pair<CompressionType, const char*>>
+    kCompressions = {
+        {CompressionType::kNoCompression, "kNoCompression"},
+        {CompressionType::kSnappyCompression, "kSnappyCompression"},
+        {CompressionType::kZlibCompression, "kZlibCompression"},
+        {CompressionType::kBZip2Compression, "kBZip2Compression"},
+        {CompressionType::kLZ4Compression, "kLZ4Compression"},
+        {CompressionType::kLZ4HCCompression, "kLZ4HCCompression"},
+        {CompressionType::kXpressCompression, "kXpressCompression"},
+        {CompressionType::kZSTD, "kZSTD"}};
+
+Status SstFileDumper::GetTableReader(const std::string& file_path) {
+  // Warning about 'magic_number' being uninitialized shows up only in UBsan
+  // builds. Though access is guarded by 's.ok()' checks, fix the issue to
+  // avoid any warnings.
+  uint64_t magic_number = Footer::kInvalidTableMagicNumber;
+
+  // read table magic number
+  Footer footer;
+
+  std::unique_ptr<RandomAccessFile> file;
+  uint64_t file_size = 0;
+  Status s = options_.env->NewRandomAccessFile(file_path, &file, soptions_);
+  if (s.ok()) {
+    s = options_.env->GetFileSize(file_path, &file_size);
+  }
+
+  file_.reset(new RandomAccessFileReader(std::move(file), file_path));
+
+  if (s.ok()) {
+    s = ReadFooterFromFile(file_.get(), nullptr /* prefetch_buffer */,
+                           file_size, &footer);
+  }
+  if (s.ok()) {
+    magic_number = footer.table_magic_number();
+  }
+
+  if (s.ok()) {
+    if (magic_number == kPlainTableMagicNumber ||
+        magic_number == kLegacyPlainTableMagicNumber) {
+      soptions_.use_mmap_reads = true;
+      options_.env->NewRandomAccessFile(file_path, &file, soptions_);
+      file_.reset(new RandomAccessFileReader(std::move(file), file_path));
+    }
+    options_.comparator = &internal_comparator_;
+    // For old sst format, ReadTableProperties might fail but file can be read
+    if (ReadTableProperties(magic_number, file_.get(), file_size).ok()) {
+      SetTableOptionsByMagicNumber(magic_number);
+    } else {
+      SetOldTableOptions();
+    }
+  }
+
+  if (s.ok()) {
+    s = NewTableReader(ioptions_, soptions_, internal_comparator_, file_size,
+                       &table_reader_);
+  }
+  return s;
+}
+
+Status SstFileDumper::NewTableReader(
+    const ImmutableCFOptions& /*ioptions*/, const EnvOptions& /*soptions*/,
+    const InternalKeyComparator& /*internal_comparator*/, uint64_t file_size,
+    std::unique_ptr<TableReader>* /*table_reader*/) {
+  // We need to turn off pre-fetching of index and filter nodes for
+  // BlockBasedTable
+  if (BlockBasedTableFactory::kName == options_.table_factory->Name()) {
+    return options_.table_factory->NewTableReader(
+        TableReaderOptions(ioptions_, moptions_.prefix_extractor.get(),
+                           soptions_, internal_comparator_),
+        std::move(file_), file_size, &table_reader_, /*enable_prefetch=*/false);
+  }
+
+  // For all other factory implementation
+  return options_.table_factory->NewTableReader(
+      TableReaderOptions(ioptions_, moptions_.prefix_extractor.get(), soptions_,
+                         internal_comparator_),
+      std::move(file_), file_size, &table_reader_);
+}
+
+Status SstFileDumper::VerifyChecksum() {
+  return table_reader_->VerifyChecksum();
+}
+
+Status SstFileDumper::DumpTable(const std::string& out_filename) {
+  std::unique_ptr<WritableFile> out_file;
+  Env* env = Env::Default();
+  env->NewWritableFile(out_filename, &out_file, soptions_);
+  Status s = table_reader_->DumpTable(out_file.get(),
+                                      moptions_.prefix_extractor.get());
+  out_file->Close();
+  return s;
+}
+
+uint64_t SstFileDumper::CalculateCompressedTableSize(
+    const TableBuilderOptions& tb_options, size_t block_size) {
+  std::unique_ptr<WritableFile> out_file;
+  std::unique_ptr<Env> env(NewMemEnv(Env::Default()));
+  env->NewWritableFile(testFileName, &out_file, soptions_);
+  std::unique_ptr<WritableFileWriter> dest_writer;
+  dest_writer.reset(
+      new WritableFileWriter(std::move(out_file), testFileName, soptions_));
+  BlockBasedTableOptions table_options;
+  table_options.block_size = block_size;
+  BlockBasedTableFactory block_based_tf(table_options);
+  std::unique_ptr<TableBuilder> table_builder;
+  table_builder.reset(block_based_tf.NewTableBuilder(
+      tb_options,
+      TablePropertiesCollectorFactory::Context::kUnknownColumnFamily,
+      dest_writer.get()));
+  std::unique_ptr<InternalIterator> iter(table_reader_->NewIterator(
+      ReadOptions(), moptions_.prefix_extractor.get()));
+  for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
+    if (!iter->status().ok()) {
+      fputs(iter->status().ToString().c_str(), stderr);
+      exit(1);
+    }
+    table_builder->Add(iter->key(), iter->value());
+  }
+  Status s = table_builder->Finish();
+  if (!s.ok()) {
+    fputs(s.ToString().c_str(), stderr);
+    exit(1);
+  }
+  uint64_t size = table_builder->FileSize();
+  env->DeleteFile(testFileName);
+  return size;
+}
+
+int SstFileDumper::ShowAllCompressionSizes(
+    size_t block_size,
+    const std::vector<std::pair<CompressionType, const char*>>&
+        compression_types) {
+  ReadOptions read_options;
+  Options opts;
+  const ImmutableCFOptions imoptions(opts);
+  const ColumnFamilyOptions cfo(opts);
+  const MutableCFOptions moptions(cfo);
+  rocksdb::InternalKeyComparator ikc(opts.comparator);
+  std::vector<std::unique_ptr<IntTblPropCollectorFactory> >
+      block_based_table_factories;
+
+  fprintf(stdout, "Block Size: %" ROCKSDB_PRIszt "\n", block_size);
+
+  for (auto& i : compression_types) {
+    if (CompressionTypeSupported(i.first)) {
+      CompressionOptions compress_opt;
+      std::string column_family_name;
+      int unknown_level = -1;
+      TableBuilderOptions tb_opts(
+          imoptions, moptions, ikc, &block_based_table_factories, i.first,
+          0 /* sample_for_compression */, compress_opt,
+          false /* skip_filters */, column_family_name, unknown_level);
+      uint64_t file_size = CalculateCompressedTableSize(tb_opts, block_size);
+      fprintf(stdout, "Compression: %s", i.second);
+      fprintf(stdout, " Size: %" PRIu64 "\n", file_size);
+    } else {
+      fprintf(stdout, "Unsupported compression type: %s.\n", i.second);
+    }
+  }
+  return 0;
+}
+
+Status SstFileDumper::ReadTableProperties(uint64_t table_magic_number,
+                                          RandomAccessFileReader* file,
+                                          uint64_t file_size) {
+  TableProperties* table_properties = nullptr;
+  Status s = rocksdb::ReadTableProperties(file, file_size, table_magic_number,
+                                          ioptions_, &table_properties);
+  if (s.ok()) {
+    table_properties_.reset(table_properties);
+  } else {
+    fprintf(stdout, "Not able to read table properties\n");
+  }
+  return s;
+}
+
+Status SstFileDumper::SetTableOptionsByMagicNumber(
+    uint64_t table_magic_number) {
+  assert(table_properties_);
+  if (table_magic_number == kBlockBasedTableMagicNumber ||
+      table_magic_number == kLegacyBlockBasedTableMagicNumber) {
+    options_.table_factory = std::make_shared<BlockBasedTableFactory>();
+    fprintf(stdout, "Sst file format: block-based\n");
+    auto& props = table_properties_->user_collected_properties;
+    auto pos = props.find(BlockBasedTablePropertyNames::kIndexType);
+    if (pos != props.end()) {
+      auto index_type_on_file = static_cast<BlockBasedTableOptions::IndexType>(
+          DecodeFixed32(pos->second.c_str()));
+      if (index_type_on_file ==
+          BlockBasedTableOptions::IndexType::kHashSearch) {
+        options_.prefix_extractor.reset(NewNoopTransform());
+      }
+    }
+  } else if (table_magic_number == kPlainTableMagicNumber ||
+             table_magic_number == kLegacyPlainTableMagicNumber) {
+    options_.allow_mmap_reads = true;
+
+    PlainTableOptions plain_table_options;
+    plain_table_options.user_key_len = kPlainTableVariableLength;
+    plain_table_options.bloom_bits_per_key = 0;
+    plain_table_options.hash_table_ratio = 0;
+    plain_table_options.index_sparseness = 1;
+    plain_table_options.huge_page_tlb_size = 0;
+    plain_table_options.encoding_type = kPlain;
+    plain_table_options.full_scan_mode = true;
+
+    options_.table_factory.reset(NewPlainTableFactory(plain_table_options));
+    fprintf(stdout, "Sst file format: plain table\n");
+  } else {
+    char error_msg_buffer[80];
+    snprintf(error_msg_buffer, sizeof(error_msg_buffer) - 1,
+             "Unsupported table magic number --- %lx",
+             (long)table_magic_number);
+    return Status::InvalidArgument(error_msg_buffer);
+  }
+
+  return Status::OK();
+}
+
+Status SstFileDumper::SetOldTableOptions() {
+  assert(table_properties_ == nullptr);
+  options_.table_factory = std::make_shared<BlockBasedTableFactory>();
+  fprintf(stdout, "Sst file format: block-based(old version)\n");
+
+  return Status::OK();
+}
+
+Status SstFileDumper::ReadSequential(bool print_kv, uint64_t read_num,
+                                     bool has_from, const std::string& from_key,
+                                     bool has_to, const std::string& to_key,
+                                     bool use_from_as_prefix) {
+  if (!table_reader_) {
+    return init_result_;
+  }
+
+  InternalIterator* iter = table_reader_->NewIterator(
+      ReadOptions(verify_checksum_, false), moptions_.prefix_extractor.get());
+  uint64_t i = 0;
+  if (has_from) {
+    InternalKey ikey;
+    ikey.SetMinPossibleForUserKey(from_key);
+    iter->Seek(ikey.Encode());
+  } else {
+    iter->SeekToFirst();
+  }
+  for (; iter->Valid(); iter->Next()) {
+    Slice key = iter->key();
+    Slice value = iter->value();
+    ++i;
+    if (read_num > 0 && i > read_num)
+      break;
+
+    ParsedInternalKey ikey;
+    if (!ParseInternalKey(key, &ikey)) {
+      std::cerr << "Internal Key ["
+                << key.ToString(true /* in hex*/)
+                << "] parse error!\n";
+      continue;
+    }
+
+    // the key returned is not prefixed with out 'from' key
+    if (use_from_as_prefix && !ikey.user_key.starts_with(from_key)) {
+      break;
+    }
+
+    // If end marker was specified, we stop before it
+    if (has_to && BytewiseComparator()->Compare(ikey.user_key, to_key) >= 0) {
+      break;
+    }
+
+    if (print_kv) {
+      fprintf(stdout, "%s => %s\n",
+          ikey.DebugString(output_hex_).c_str(),
+          value.ToString(output_hex_).c_str());
+    }
+  }
+
+  read_num_ += i;
+
+  Status ret = iter->status();
+  delete iter;
+  return ret;
+}
+
+Status SstFileDumper::ReadTableProperties(
+    std::shared_ptr<const TableProperties>* table_properties) {
+  if (!table_reader_) {
+    return init_result_;
+  }
+
+  *table_properties = table_reader_->GetTableProperties();
+  return init_result_;
+}
+
+namespace {
+
+void print_help() {
+  fprintf(stderr,
+          R"(sst_dump --file=<data_dir_OR_sst_file> [--command=check|scan|raw]
+    --file=<data_dir_OR_sst_file>
+      Path to SST file or directory containing SST files
+
+    --command=check|scan|raw|verify
+        check: Iterate over entries in files but dont print anything except if an error is encounterd (default command)
+        scan: Iterate over entries in files and print them to screen
+        raw: Dump all the table contents to <file_name>_dump.txt
+        verify: Iterate all the blocks in files verifying checksum to detect possible coruption but dont print anything except if a corruption is encountered
+        recompress: reports the SST file size if recompressed with different
+                    compression types
+
+    --output_hex
+      Can be combined with scan command to print the keys and values in Hex
+
+    --from=<user_key>
+      Key to start reading from when executing check|scan
+
+    --to=<user_key>
+      Key to stop reading at when executing check|scan
+
+    --prefix=<user_key>
+      Returns all keys with this prefix when executing check|scan
+      Cannot be used in conjunction with --from
+
+    --read_num=<num>
+      Maximum number of entries to read when executing check|scan
+
+    --verify_checksum
+      Verify file checksum when executing check|scan
+
+    --input_key_hex
+      Can be combined with --from and --to to indicate that these values are encoded in Hex
+
+    --show_properties
+      Print table properties after iterating over the file when executing
+      check|scan|raw
+
+    --set_block_size=<block_size>
+      Can be combined with --command=recompress to set the block size that will
+      be used when trying different compression algorithms
+
+    --compression_types=<comma-separated list of CompressionType members, e.g.,
+      kSnappyCompression>
+      Can be combined with --command=recompress to run recompression for this
+      list of compression types
+
+    --parse_internal_key=<0xKEY>
+      Convenience option to parse an internal key on the command line. Dumps the
+      internal key in hex format {'key' @ SN: type}
+)");
+}
+
+}  // namespace
+
+int SSTDumpTool::Run(int argc, char** argv, Options options) {
+  const char* dir_or_file = nullptr;
+  uint64_t read_num = std::numeric_limits<uint64_t>::max();
+  std::string command;
+
+  char junk;
+  uint64_t n;
+  bool verify_checksum = false;
+  bool output_hex = false;
+  bool input_key_hex = false;
+  bool has_from = false;
+  bool has_to = false;
+  bool use_from_as_prefix = false;
+  bool show_properties = false;
+  bool show_summary = false;
+  bool set_block_size = false;
+  std::string from_key;
+  std::string to_key;
+  std::string block_size_str;
+  size_t block_size = 0;
+  std::vector<std::pair<CompressionType, const char*>> compression_types;
+  uint64_t total_num_files = 0;
+  uint64_t total_num_data_blocks = 0;
+  uint64_t total_data_block_size = 0;
+  uint64_t total_index_block_size = 0;
+  uint64_t total_filter_block_size = 0;
+  for (int i = 1; i < argc; i++) {
+    if (strncmp(argv[i], "--file=", 7) == 0) {
+      dir_or_file = argv[i] + 7;
+    } else if (strcmp(argv[i], "--output_hex") == 0) {
+      output_hex = true;
+    } else if (strcmp(argv[i], "--input_key_hex") == 0) {
+      input_key_hex = true;
+    } else if (sscanf(argv[i],
+               "--read_num=%lu%c",
+               (unsigned long*)&n, &junk) == 1) {
+      read_num = n;
+    } else if (strcmp(argv[i], "--verify_checksum") == 0) {
+      verify_checksum = true;
+    } else if (strncmp(argv[i], "--command=", 10) == 0) {
+      command = argv[i] + 10;
+    } else if (strncmp(argv[i], "--from=", 7) == 0) {
+      from_key = argv[i] + 7;
+      has_from = true;
+    } else if (strncmp(argv[i], "--to=", 5) == 0) {
+      to_key = argv[i] + 5;
+      has_to = true;
+    } else if (strncmp(argv[i], "--prefix=", 9) == 0) {
+      from_key = argv[i] + 9;
+      use_from_as_prefix = true;
+    } else if (strcmp(argv[i], "--show_properties") == 0) {
+      show_properties = true;
+    } else if (strcmp(argv[i], "--show_summary") == 0) {
+      show_summary = true;
+    } else if (strncmp(argv[i], "--set_block_size=", 17) == 0) {
+      set_block_size = true;
+      block_size_str = argv[i] + 17;
+      std::istringstream iss(block_size_str);
+      iss >> block_size;
+      if (iss.fail()) {
+        fprintf(stderr, "block size must be numeric\n");
+        exit(1);
+      }
+    } else if (strncmp(argv[i], "--compression_types=", 20) == 0) {
+      std::string compression_types_csv = argv[i] + 20;
+      std::istringstream iss(compression_types_csv);
+      std::string compression_type;
+      while (std::getline(iss, compression_type, ',')) {
+        auto iter = std::find_if(
+            kCompressions.begin(), kCompressions.end(),
+            [&compression_type](std::pair<CompressionType, const char*> curr) {
+              return curr.second == compression_type;
+            });
+        if (iter == kCompressions.end()) {
+          fprintf(stderr, "%s is not a valid CompressionType\n",
+                  compression_type.c_str());
+          exit(1);
+        }
+        compression_types.emplace_back(*iter);
+      }
+    } else if (strncmp(argv[i], "--parse_internal_key=", 21) == 0) {
+      std::string in_key(argv[i] + 21);
+      try {
+        in_key = rocksdb::LDBCommand::HexToString(in_key);
+      } catch (...) {
+        std::cerr << "ERROR: Invalid key input '"
+          << in_key
+          << "' Use 0x{hex representation of internal rocksdb key}" << std::endl;
+        return -1;
+      }
+      Slice sl_key = rocksdb::Slice(in_key);
+      ParsedInternalKey ikey;
+      int retc = 0;
+      if (!ParseInternalKey(sl_key, &ikey)) {
+        std::cerr << "Internal Key [" << sl_key.ToString(true /* in hex*/)
+                  << "] parse error!\n";
+        retc = -1;
+      }
+      fprintf(stdout, "key=%s\n", ikey.DebugString(true).c_str());
+      return retc;
+    } else {
+      fprintf(stderr, "Unrecognized argument '%s'\n\n", argv[i]);
+      print_help();
+      exit(1);
+    }
+  }
+
+  if (use_from_as_prefix && has_from) {
+    fprintf(stderr, "Cannot specify --prefix and --from\n\n");
+    exit(1);
+  }
+
+  if (input_key_hex) {
+    if (has_from || use_from_as_prefix) {
+      from_key = rocksdb::LDBCommand::HexToString(from_key);
+    }
+    if (has_to) {
+      to_key = rocksdb::LDBCommand::HexToString(to_key);
+    }
+  }
+
+  if (dir_or_file == nullptr) {
+    fprintf(stderr, "file or directory must be specified.\n\n");
+    print_help();
+    exit(1);
+  }
+
+  std::vector<std::string> filenames;
+  rocksdb::Env* env = options.env;
+  rocksdb::Status st = env->GetChildren(dir_or_file, &filenames);
+  bool dir = true;
+  if (!st.ok()) {
+    filenames.clear();
+    filenames.push_back(dir_or_file);
+    dir = false;
+  }
+
+  fprintf(stdout, "from [%s] to [%s]\n",
+      rocksdb::Slice(from_key).ToString(true).c_str(),
+      rocksdb::Slice(to_key).ToString(true).c_str());
+
+  uint64_t total_read = 0;
+  for (size_t i = 0; i < filenames.size(); i++) {
+    std::string filename = filenames.at(i);
+    if (filename.length() <= 4 ||
+        filename.rfind(".sst") != filename.length() - 4) {
+      // ignore
+      continue;
+    }
+    if (dir) {
+      filename = std::string(dir_or_file) + "/" + filename;
+    }
+
+    rocksdb::SstFileDumper dumper(options, filename, verify_checksum,
+                                  output_hex);
+    if (!dumper.getStatus().ok()) {
+      fprintf(stderr, "%s: %s\n", filename.c_str(),
+              dumper.getStatus().ToString().c_str());
+      continue;
+    }
+
+    if (command == "recompress") {
+      dumper.ShowAllCompressionSizes(
+          set_block_size ? block_size : 16384,
+          compression_types.empty() ? kCompressions : compression_types);
+      return 0;
+    }
+
+    if (command == "raw") {
+      std::string out_filename = filename.substr(0, filename.length() - 4);
+      out_filename.append("_dump.txt");
+
+      st = dumper.DumpTable(out_filename);
+      if (!st.ok()) {
+        fprintf(stderr, "%s: %s\n", filename.c_str(), st.ToString().c_str());
+        exit(1);
+      } else {
+        fprintf(stdout, "raw dump written to file %s\n", &out_filename[0]);
+      }
+      continue;
+    }
+
+    // scan all files in give file path.
+    if (command == "" || command == "scan" || command == "check") {
+      st = dumper.ReadSequential(
+          command == "scan", read_num > 0 ? (read_num - total_read) : read_num,
+          has_from || use_from_as_prefix, from_key, has_to, to_key,
+          use_from_as_prefix);
+      if (!st.ok()) {
+        fprintf(stderr, "%s: %s\n", filename.c_str(),
+            st.ToString().c_str());
+      }
+      total_read += dumper.GetReadNumber();
+      if (read_num > 0 && total_read > read_num) {
+        break;
+      }
+    }
+
+    if (command == "verify") {
+      st = dumper.VerifyChecksum();
+      if (!st.ok()) {
+        fprintf(stderr, "%s is corrupted: %s\n", filename.c_str(),
+                st.ToString().c_str());
+      } else {
+        fprintf(stdout, "The file is ok\n");
+      }
+      continue;
+    }
+
+    if (show_properties || show_summary) {
+      const rocksdb::TableProperties* table_properties;
+
+      std::shared_ptr<const rocksdb::TableProperties>
+          table_properties_from_reader;
+      st = dumper.ReadTableProperties(&table_properties_from_reader);
+      if (!st.ok()) {
+        fprintf(stderr, "%s: %s\n", filename.c_str(), st.ToString().c_str());
+        fprintf(stderr, "Try to use initial table properties\n");
+        table_properties = dumper.GetInitTableProperties();
+      } else {
+        table_properties = table_properties_from_reader.get();
+      }
+      if (table_properties != nullptr) {
+        if (show_properties) {
+          fprintf(stdout,
+                  "Table Properties:\n"
+                  "------------------------------\n"
+                  "  %s",
+                  table_properties->ToString("\n  ", ": ").c_str());
+        }
+        total_num_files += 1;
+        total_num_data_blocks += table_properties->num_data_blocks;
+        total_data_block_size += table_properties->data_size;
+        total_index_block_size += table_properties->index_size;
+        total_filter_block_size += table_properties->filter_size;
+      }
+      if (show_properties) {
+        fprintf(stdout,
+                "Raw user collected properties\n"
+                "------------------------------\n");
+        for (const auto& kv : table_properties->user_collected_properties) {
+          std::string prop_name = kv.first;
+          std::string prop_val = Slice(kv.second).ToString(true);
+          fprintf(stdout, "  # %s: 0x%s\n", prop_name.c_str(),
+                  prop_val.c_str());
+        }
+      }
+    }
+  }
+  if (show_summary) {
+    fprintf(stdout, "total number of files: %" PRIu64 "\n", total_num_files);
+    fprintf(stdout, "total number of data blocks: %" PRIu64 "\n",
+            total_num_data_blocks);
+    fprintf(stdout, "total data block size: %" PRIu64 "\n",
+            total_data_block_size);
+    fprintf(stdout, "total index block size: %" PRIu64 "\n",
+            total_index_block_size);
+    fprintf(stdout, "total filter block size: %" PRIu64 "\n",
+            total_filter_block_size);
+  }
+  return 0;
+}
+}  // namespace rocksdb
+
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/sst_dump_tool_imp.h b/src/rocksdb/tools/sst_dump_tool_imp.h
new file mode 100644
index 00000000..846738a4
--- /dev/null
+++ b/src/rocksdb/tools/sst_dump_tool_imp.h
@@ -0,0 +1,84 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+#pragma once
+#ifndef ROCKSDB_LITE
+
+#include "rocksdb/sst_dump_tool.h"
+
+#include <memory>
+#include <string>
+#include "db/dbformat.h"
+#include "options/cf_options.h"
+#include "util/file_reader_writer.h"
+
+namespace rocksdb {
+
+class SstFileDumper {
+ public:
+  explicit SstFileDumper(const Options& options, const std::string& file_name,
+                         bool verify_checksum, bool output_hex);
+
+  Status ReadSequential(bool print_kv, uint64_t read_num, bool has_from,
+                        const std::string& from_key, bool has_to,
+                        const std::string& to_key,
+                        bool use_from_as_prefix = false);
+
+  Status ReadTableProperties(
+      std::shared_ptr<const TableProperties>* table_properties);
+  uint64_t GetReadNumber() { return read_num_; }
+  TableProperties* GetInitTableProperties() { return table_properties_.get(); }
+
+  Status VerifyChecksum();
+  Status DumpTable(const std::string& out_filename);
+  Status getStatus() { return init_result_; }
+
+  int ShowAllCompressionSizes(
+      size_t block_size,
+      const std::vector<std::pair<CompressionType, const char*>>&
+          compression_types);
+
+ private:
+  // Get the TableReader implementation for the sst file
+  Status GetTableReader(const std::string& file_path);
+  Status ReadTableProperties(uint64_t table_magic_number,
+                             RandomAccessFileReader* file, uint64_t file_size);
+
+  uint64_t CalculateCompressedTableSize(const TableBuilderOptions& tb_options,
+                                        size_t block_size);
+
+  Status SetTableOptionsByMagicNumber(uint64_t table_magic_number);
+  Status SetOldTableOptions();
+
+  // Helper function to call the factory with settings specific to the
+  // factory implementation
+  Status NewTableReader(const ImmutableCFOptions& ioptions,
+                        const EnvOptions& soptions,
+                        const InternalKeyComparator& internal_comparator,
+                        uint64_t file_size,
+                        std::unique_ptr<TableReader>* table_reader);
+
+  std::string file_name_;
+  uint64_t read_num_;
+  bool verify_checksum_;
+  bool output_hex_;
+  EnvOptions soptions_;
+
+  // options_ and internal_comparator_ will also be used in
+  // ReadSequential internally (specifically, seek-related operations)
+  Options options_;
+
+  Status init_result_;
+  std::unique_ptr<TableReader> table_reader_;
+  std::unique_ptr<RandomAccessFileReader> file_;
+
+  const ImmutableCFOptions ioptions_;
+  const MutableCFOptions moptions_;
+  InternalKeyComparator internal_comparator_;
+  std::unique_ptr<TableProperties> table_properties_;
+};
+
+}  // namespace rocksdb
+
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/trace_analyzer.cc b/src/rocksdb/tools/trace_analyzer.cc
new file mode 100644
index 00000000..2aa84fd3
--- /dev/null
+++ b/src/rocksdb/tools/trace_analyzer.cc
@@ -0,0 +1,25 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+#ifndef ROCKSDB_LITE
+#ifndef GFLAGS
+#include <cstdio>
+int main() {
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+  return 1;
+}
+#else
+#include "tools/trace_analyzer_tool.h"
+int main(int argc, char** argv) {
+  return rocksdb::trace_analyzer_tool(argc, argv);
+}
+#endif
+#else
+#include <stdio.h>
+int main(int /*argc*/, char** /*argv*/) {
+  fprintf(stderr, "Not supported in lite mode.\n");
+  return 1;
+}
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/trace_analyzer_test.cc b/src/rocksdb/tools/trace_analyzer_test.cc
new file mode 100644
index 00000000..b2cc777d
--- /dev/null
+++ b/src/rocksdb/tools/trace_analyzer_test.cc
@@ -0,0 +1,721 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#ifndef ROCKSDB_LITE
+#ifndef GFLAGS
+#include <cstdio>
+int main() {
+  fprintf(stderr, "Please install gflags to run trace_analyzer test\n");
+  return 1;
+}
+#else
+
+#include <chrono>
+#include <cstdio>
+#include <cstdlib>
+#include <sstream>
+#include <thread>
+
+#include "db/db_test_util.h"
+#include "rocksdb/db.h"
+#include "rocksdb/env.h"
+#include "rocksdb/status.h"
+#include "rocksdb/trace_reader_writer.h"
+#include "tools/trace_analyzer_tool.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+#include "util/trace_replay.h"
+
+namespace rocksdb {
+
+namespace {
+static const int kMaxArgCount = 100;
+static const size_t kArgBufferSize = 100000;
+}  // namespace
+
+// The helper functions for the test
+class TraceAnalyzerTest : public testing::Test {
+ public:
+  TraceAnalyzerTest() : rnd_(0xFB) {
+    // test_path_ = test::TmpDir() + "trace_analyzer_test";
+    test_path_ = test::PerThreadDBPath("trace_analyzer_test");
+    env_ = rocksdb::Env::Default();
+    env_->CreateDir(test_path_);
+    dbname_ = test_path_ + "/db";
+  }
+
+  ~TraceAnalyzerTest() override {}
+
+  void GenerateTrace(std::string trace_path) {
+    Options options;
+    options.create_if_missing = true;
+    options.merge_operator = MergeOperators::CreatePutOperator();
+    ReadOptions ro;
+    WriteOptions wo;
+    TraceOptions trace_opt;
+    DB* db_ = nullptr;
+    std::string value;
+    std::unique_ptr<TraceWriter> trace_writer;
+    Iterator* single_iter = nullptr;
+
+    ASSERT_OK(
+        NewFileTraceWriter(env_, env_options_, trace_path, &trace_writer));
+    ASSERT_OK(DB::Open(options, dbname_, &db_));
+    ASSERT_OK(db_->StartTrace(trace_opt, std::move(trace_writer)));
+
+    WriteBatch batch;
+    ASSERT_OK(batch.Put("a", "aaaaaaaaa"));
+    ASSERT_OK(batch.Merge("b", "aaaaaaaaaaaaaaaaaaaa"));
+    ASSERT_OK(batch.Delete("c"));
+    ASSERT_OK(batch.SingleDelete("d"));
+    ASSERT_OK(batch.DeleteRange("e", "f"));
+    ASSERT_OK(db_->Write(wo, &batch));
+
+    ASSERT_OK(db_->Get(ro, "a", &value));
+    single_iter = db_->NewIterator(ro);
+    single_iter->Seek("a");
+    single_iter->SeekForPrev("b");
+    delete single_iter;
+    std::this_thread::sleep_for (std::chrono::seconds(1));
+
+    db_->Get(ro, "g", &value);
+
+    ASSERT_OK(db_->EndTrace());
+
+    ASSERT_OK(env_->FileExists(trace_path));
+
+    std::unique_ptr<WritableFile> whole_f;
+    std::string whole_path = test_path_ + "/0.txt";
+    ASSERT_OK(env_->NewWritableFile(whole_path, &whole_f, env_options_));
+    std::string whole_str = "0x61\n0x62\n0x63\n0x64\n0x65\n0x66\n";
+    ASSERT_OK(whole_f->Append(whole_str));
+    delete db_;
+    ASSERT_OK(DestroyDB(dbname_, options));
+  }
+
+  void RunTraceAnalyzer(const std::vector<std::string>& args) {
+    char arg_buffer[kArgBufferSize];
+    char* argv[kMaxArgCount];
+    int argc = 0;
+    int cursor = 0;
+
+    for (const auto& arg : args) {
+      ASSERT_LE(cursor + arg.size() + 1, kArgBufferSize);
+      ASSERT_LE(argc + 1, kMaxArgCount);
+      snprintf(arg_buffer + cursor, arg.size() + 1, "%s", arg.c_str());
+
+      argv[argc++] = arg_buffer + cursor;
+      cursor += static_cast<int>(arg.size()) + 1;
+    }
+
+    ASSERT_EQ(0, rocksdb::trace_analyzer_tool(argc, argv));
+  }
+
+  void CheckFileContent(const std::vector<std::string>& cnt,
+                        std::string file_path, bool full_content) {
+    ASSERT_OK(env_->FileExists(file_path));
+    std::unique_ptr<SequentialFile> f_ptr;
+    ASSERT_OK(env_->NewSequentialFile(file_path, &f_ptr, env_options_));
+
+    std::string get_line;
+    std::istringstream iss;
+    bool has_data = true;
+    std::vector<std::string> result;
+    uint32_t count;
+    Status s;
+    for (count = 0; ReadOneLine(&iss, f_ptr.get(), &get_line, &has_data, &s);
+         ++count) {
+      ASSERT_OK(s);
+      result.push_back(get_line);
+    }
+
+    ASSERT_EQ(cnt.size(), result.size());
+    for (int i = 0; i < static_cast<int>(result.size()); i++) {
+      if (full_content) {
+        ASSERT_EQ(result[i], cnt[i]);
+      } else {
+        ASSERT_EQ(result[i][0], cnt[i][0]);
+      }
+    }
+
+    return;
+  }
+
+  void AnalyzeTrace(std::vector<std::string>& paras_diff,
+                    std::string output_path, std::string trace_path) {
+    std::vector<std::string> paras = {"./trace_analyzer",
+                                      "-convert_to_human_readable_trace",
+                                      "-output_key_stats",
+                                      "-output_access_count_stats",
+                                      "-output_prefix=test",
+                                      "-output_prefix_cut=1",
+                                      "-output_time_series",
+                                      "-output_value_distribution",
+                                      "-output_qps_stats",
+                                      "-no_key",
+                                      "-no_print"};
+    for (auto& para : paras_diff) {
+      paras.push_back(para);
+    }
+    Status s = env_->FileExists(trace_path);
+    if (!s.ok()) {
+      GenerateTrace(trace_path);
+    }
+    env_->CreateDir(output_path);
+    RunTraceAnalyzer(paras);
+  }
+
+  rocksdb::Env* env_;
+  EnvOptions env_options_;
+  std::string test_path_;
+  std::string dbname_;
+  Random rnd_;
+};
+
+TEST_F(TraceAnalyzerTest, Get) {
+  std::string trace_path = test_path_ + "/trace";
+  std::string output_path = test_path_ + "/get";
+  std::string file_path;
+  std::vector<std::string> paras = {"-analyze_get"};
+  paras.push_back("-output_dir=" + output_path);
+  paras.push_back("-trace_path=" + trace_path);
+  paras.push_back("-key_space_dir=" + test_path_);
+  AnalyzeTrace(paras, output_path, trace_path);
+
+  // check the key_stats file
+  std::vector<std::string> k_stats = {"0 10 0 1 1.000000", "0 10 1 1 1.000000"};
+  file_path = output_path + "/test-get-0-accessed_key_stats.txt";
+  CheckFileContent(k_stats, file_path, true);
+
+  // Check the access count distribution
+  std::vector<std::string> k_dist = {"access_count: 1 num: 2"};
+  file_path = output_path + "/test-get-0-accessed_key_count_distribution.txt";
+  CheckFileContent(k_dist, file_path, true);
+
+  // Check the trace sequence
+  std::vector<std::string> k_sequence = {"1", "5", "2", "3", "4",
+                                         "0", "6", "7", "0"};
+  file_path = output_path + "/test-human_readable_trace.txt";
+  CheckFileContent(k_sequence, file_path, false);
+
+  // Check the prefix
+  std::vector<std::string> k_prefix = {"0 0 0 0.000000 0.000000 0x30",
+                                       "1 1 1 1.000000 1.000000 0x61"};
+  file_path = output_path + "/test-get-0-accessed_key_prefix_cut.txt";
+  CheckFileContent(k_prefix, file_path, true);
+
+  // Check the time series
+  std::vector<std::string> k_series = {"0 1533000630 0", "0 1533000630 1"};
+  file_path = output_path + "/test-get-0-time_series.txt";
+  CheckFileContent(k_series, file_path, false);
+
+  // Check the accessed key in whole key space
+  std::vector<std::string> k_whole_access = {"0 1"};
+  file_path = output_path + "/test-get-0-whole_key_stats.txt";
+  CheckFileContent(k_whole_access, file_path, true);
+
+  // Check the whole key prefix cut
+  std::vector<std::string> k_whole_prefix = {"0 0x61", "1 0x62", "2 0x63",
+                                             "3 0x64", "4 0x65", "5 0x66"};
+  file_path = output_path + "/test-get-0-whole_key_prefix_cut.txt";
+  CheckFileContent(k_whole_prefix, file_path, true);
+
+  // Check the overall qps
+  std::vector<std::string> all_qps = {"1 0 0 0 0 0 0 0 1"};
+  file_path = output_path + "/test-qps_stats.txt";
+  CheckFileContent(all_qps, file_path, true);
+
+  // Check the qps of get
+  std::vector<std::string> get_qps = {"1"};
+  file_path = output_path + "/test-get-0-qps_stats.txt";
+  CheckFileContent(get_qps, file_path, true);
+
+  // Check the top k qps prefix cut
+  std::vector<std::string> top_qps = {"At time: 0 with QPS: 1",
+                                      "The prefix: 0x61 Access count: 1"};
+  file_path = output_path + "/test-get-0-accessed_top_k_qps_prefix_cut.txt";
+  CheckFileContent(top_qps, file_path, true);
+}
+
+// Test analyzing of Put
+TEST_F(TraceAnalyzerTest, Put) {
+  std::string trace_path = test_path_ + "/trace";
+  std::string output_path = test_path_ + "/put";
+  std::string file_path;
+  std::vector<std::string> paras = {"-analyze_put"};
+  paras.push_back("-output_dir=" + output_path);
+  paras.push_back("-trace_path=" + trace_path);
+  paras.push_back("-key_space_dir=" + test_path_);
+  AnalyzeTrace(paras, output_path, trace_path);
+
+  // check the key_stats file
+  std::vector<std::string> k_stats = {"0 9 0 1 1.000000"};
+  file_path = output_path + "/test-put-0-accessed_key_stats.txt";
+  CheckFileContent(k_stats, file_path, true);
+
+  // Check the access count distribution
+  std::vector<std::string> k_dist = {"access_count: 1 num: 1"};
+  file_path = output_path + "/test-put-0-accessed_key_count_distribution.txt";
+  CheckFileContent(k_dist, file_path, true);
+
+  // Check the trace sequence
+  std::vector<std::string> k_sequence = {"1", "5", "2", "3", "4",
+                                         "0", "6", "7", "0"};
+  file_path = output_path + "/test-human_readable_trace.txt";
+  CheckFileContent(k_sequence, file_path, false);
+
+  // Check the prefix
+  std::vector<std::string> k_prefix = {"0 0 0 0.000000 0.000000 0x30"};
+  file_path = output_path + "/test-put-0-accessed_key_prefix_cut.txt";
+  CheckFileContent(k_prefix, file_path, true);
+
+  // Check the time series
+  std::vector<std::string> k_series = {"1 1533056278 0"};
+  file_path = output_path + "/test-put-0-time_series.txt";
+  CheckFileContent(k_series, file_path, false);
+
+  // Check the accessed key in whole key space
+  std::vector<std::string> k_whole_access = {"0 1"};
+  file_path = output_path + "/test-put-0-whole_key_stats.txt";
+  CheckFileContent(k_whole_access, file_path, true);
+
+  // Check the whole key prefix cut
+  std::vector<std::string> k_whole_prefix = {"0 0x61", "1 0x62", "2 0x63",
+                                             "3 0x64", "4 0x65", "5 0x66"};
+  file_path = output_path + "/test-put-0-whole_key_prefix_cut.txt";
+  CheckFileContent(k_whole_prefix, file_path, true);
+
+  // Check the overall qps
+  std::vector<std::string> all_qps = {"1 1 0 0 0 0 0 0 2"};
+  file_path = output_path + "/test-qps_stats.txt";
+  CheckFileContent(all_qps, file_path, true);
+
+  // Check the qps of Put
+  std::vector<std::string> get_qps = {"1"};
+  file_path = output_path + "/test-put-0-qps_stats.txt";
+  CheckFileContent(get_qps, file_path, true);
+
+  // Check the top k qps prefix cut
+  std::vector<std::string> top_qps = {"At time: 0 with QPS: 1",
+                                      "The prefix: 0x61 Access count: 1"};
+  file_path = output_path + "/test-put-0-accessed_top_k_qps_prefix_cut.txt";
+  CheckFileContent(top_qps, file_path, true);
+
+  // Check the value size distribution
+  std::vector<std::string> value_dist = {
+      "Number_of_value_size_between 0 and 16 is: 1"};
+  file_path = output_path + "/test-put-0-accessed_value_size_distribution.txt";
+  CheckFileContent(value_dist, file_path, true);
+}
+
+// Test analyzing of delete
+TEST_F(TraceAnalyzerTest, Delete) {
+  std::string trace_path = test_path_ + "/trace";
+  std::string output_path = test_path_ + "/delete";
+  std::string file_path;
+  std::vector<std::string> paras = {"-analyze_delete"};
+  paras.push_back("-output_dir=" + output_path);
+  paras.push_back("-trace_path=" + trace_path);
+  paras.push_back("-key_space_dir=" + test_path_);
+  AnalyzeTrace(paras, output_path, trace_path);
+
+  // check the key_stats file
+  std::vector<std::string> k_stats = {"0 0 0 1 1.000000"};
+  file_path = output_path + "/test-delete-0-accessed_key_stats.txt";
+  CheckFileContent(k_stats, file_path, true);
+
+  // Check the access count distribution
+  std::vector<std::string> k_dist = {"access_count: 1 num: 1"};
+  file_path =
+      output_path + "/test-delete-0-accessed_key_count_distribution.txt";
+  CheckFileContent(k_dist, file_path, true);
+
+  // Check the trace sequence
+  std::vector<std::string> k_sequence = {"1", "5", "2", "3", "4",
+                                         "0", "6", "7", "0"};
+  file_path = output_path + "/test-human_readable_trace.txt";
+  CheckFileContent(k_sequence, file_path, false);
+
+  // Check the prefix
+  std::vector<std::string> k_prefix = {"0 0 0 0.000000 0.000000 0x30"};
+  file_path = output_path + "/test-delete-0-accessed_key_prefix_cut.txt";
+  CheckFileContent(k_prefix, file_path, true);
+
+  // Check the time series
+  std::vector<std::string> k_series = {"2 1533000630 0"};
+  file_path = output_path + "/test-delete-0-time_series.txt";
+  CheckFileContent(k_series, file_path, false);
+
+  // Check the accessed key in whole key space
+  std::vector<std::string> k_whole_access = {"2 1"};
+  file_path = output_path + "/test-delete-0-whole_key_stats.txt";
+  CheckFileContent(k_whole_access, file_path, true);
+
+  // Check the whole key prefix cut
+  std::vector<std::string> k_whole_prefix = {"0 0x61", "1 0x62", "2 0x63",
+                                             "3 0x64", "4 0x65", "5 0x66"};
+  file_path = output_path + "/test-delete-0-whole_key_prefix_cut.txt";
+  CheckFileContent(k_whole_prefix, file_path, true);
+
+  // Check the overall qps
+  std::vector<std::string> all_qps = {"1 1 1 0 0 0 0 0 3"};
+  file_path = output_path + "/test-qps_stats.txt";
+  CheckFileContent(all_qps, file_path, true);
+
+  // Check the qps of Delete
+  std::vector<std::string> get_qps = {"1"};
+  file_path = output_path + "/test-delete-0-qps_stats.txt";
+  CheckFileContent(get_qps, file_path, true);
+
+  // Check the top k qps prefix cut
+  std::vector<std::string> top_qps = {"At time: 0 with QPS: 1",
+                                      "The prefix: 0x63 Access count: 1"};
+  file_path = output_path + "/test-delete-0-accessed_top_k_qps_prefix_cut.txt";
+  CheckFileContent(top_qps, file_path, true);
+}
+
+// Test analyzing of Merge
+TEST_F(TraceAnalyzerTest, Merge) {
+  std::string trace_path = test_path_ + "/trace";
+  std::string output_path = test_path_ + "/merge";
+  std::string file_path;
+  std::vector<std::string> paras = {"-analyze_merge"};
+  paras.push_back("-output_dir=" + output_path);
+  paras.push_back("-trace_path=" + trace_path);
+  paras.push_back("-key_space_dir=" + test_path_);
+  AnalyzeTrace(paras, output_path, trace_path);
+
+  // check the key_stats file
+  std::vector<std::string> k_stats = {"0 20 0 1 1.000000"};
+  file_path = output_path + "/test-merge-0-accessed_key_stats.txt";
+  CheckFileContent(k_stats, file_path, true);
+
+  // Check the access count distribution
+  std::vector<std::string> k_dist = {"access_count: 1 num: 1"};
+  file_path = output_path + "/test-merge-0-accessed_key_count_distribution.txt";
+  CheckFileContent(k_dist, file_path, true);
+
+  // Check the trace sequence
+  std::vector<std::string> k_sequence = {"1", "5", "2", "3", "4",
+                                         "0", "6", "7", "0"};
+  file_path = output_path + "/test-human_readable_trace.txt";
+  CheckFileContent(k_sequence, file_path, false);
+
+  // Check the prefix
+  std::vector<std::string> k_prefix = {"0 0 0 0.000000 0.000000 0x30"};
+  file_path = output_path + "/test-merge-0-accessed_key_prefix_cut.txt";
+  CheckFileContent(k_prefix, file_path, true);
+
+  // Check the time series
+  std::vector<std::string> k_series = {"5 1533000630 0"};
+  file_path = output_path + "/test-merge-0-time_series.txt";
+  CheckFileContent(k_series, file_path, false);
+
+  // Check the accessed key in whole key space
+  std::vector<std::string> k_whole_access = {"1 1"};
+  file_path = output_path + "/test-merge-0-whole_key_stats.txt";
+  CheckFileContent(k_whole_access, file_path, true);
+
+  // Check the whole key prefix cut
+  std::vector<std::string> k_whole_prefix = {"0 0x61", "1 0x62", "2 0x63",
+                                             "3 0x64", "4 0x65", "5 0x66"};
+  file_path = output_path + "/test-merge-0-whole_key_prefix_cut.txt";
+  CheckFileContent(k_whole_prefix, file_path, true);
+
+  // Check the overall qps
+  std::vector<std::string> all_qps = {"1 1 1 0 0 1 0 0 4"};
+  file_path = output_path + "/test-qps_stats.txt";
+  CheckFileContent(all_qps, file_path, true);
+
+  // Check the qps of Merge
+  std::vector<std::string> get_qps = {"1"};
+  file_path = output_path + "/test-merge-0-qps_stats.txt";
+  CheckFileContent(get_qps, file_path, true);
+
+  // Check the top k qps prefix cut
+  std::vector<std::string> top_qps = {"At time: 0 with QPS: 1",
+                                      "The prefix: 0x62 Access count: 1"};
+  file_path = output_path + "/test-merge-0-accessed_top_k_qps_prefix_cut.txt";
+  CheckFileContent(top_qps, file_path, true);
+
+  // Check the value size distribution
+  std::vector<std::string> value_dist = {
+      "Number_of_value_size_between 0 and 24 is: 1"};
+  file_path =
+      output_path + "/test-merge-0-accessed_value_size_distribution.txt";
+  CheckFileContent(value_dist, file_path, true);
+}
+
+// Test analyzing of SingleDelete
+TEST_F(TraceAnalyzerTest, SingleDelete) {
+  std::string trace_path = test_path_ + "/trace";
+  std::string output_path = test_path_ + "/single_delete";
+  std::string file_path;
+  std::vector<std::string> paras = {"-analyze_single_delete"};
+  paras.push_back("-output_dir=" + output_path);
+  paras.push_back("-trace_path=" + trace_path);
+  paras.push_back("-key_space_dir=" + test_path_);
+  AnalyzeTrace(paras, output_path, trace_path);
+
+  // check the key_stats file
+  std::vector<std::string> k_stats = {"0 0 0 1 1.000000"};
+  file_path = output_path + "/test-single_delete-0-accessed_key_stats.txt";
+  CheckFileContent(k_stats, file_path, true);
+
+  // Check the access count distribution
+  std::vector<std::string> k_dist = {"access_count: 1 num: 1"};
+  file_path =
+      output_path + "/test-single_delete-0-accessed_key_count_distribution.txt";
+  CheckFileContent(k_dist, file_path, true);
+
+  // Check the trace sequence
+  std::vector<std::string> k_sequence = {"1", "5", "2", "3", "4",
+                                         "0", "6", "7", "0"};
+  file_path = output_path + "/test-human_readable_trace.txt";
+  CheckFileContent(k_sequence, file_path, false);
+
+  // Check the prefix
+  std::vector<std::string> k_prefix = {"0 0 0 0.000000 0.000000 0x30"};
+  file_path = output_path + "/test-single_delete-0-accessed_key_prefix_cut.txt";
+  CheckFileContent(k_prefix, file_path, true);
+
+  // Check the time series
+  std::vector<std::string> k_series = {"3 1533000630 0"};
+  file_path = output_path + "/test-single_delete-0-time_series.txt";
+  CheckFileContent(k_series, file_path, false);
+
+  // Check the accessed key in whole key space
+  std::vector<std::string> k_whole_access = {"3 1"};
+  file_path = output_path + "/test-single_delete-0-whole_key_stats.txt";
+  CheckFileContent(k_whole_access, file_path, true);
+
+  // Check the whole key prefix cut
+  std::vector<std::string> k_whole_prefix = {"0 0x61", "1 0x62", "2 0x63",
+                                             "3 0x64", "4 0x65", "5 0x66"};
+  file_path = output_path + "/test-single_delete-0-whole_key_prefix_cut.txt";
+  CheckFileContent(k_whole_prefix, file_path, true);
+
+  // Check the overall qps
+  std::vector<std::string> all_qps = {"1 1 1 1 0 1 0 0 5"};
+  file_path = output_path + "/test-qps_stats.txt";
+  CheckFileContent(all_qps, file_path, true);
+
+  // Check the qps of SingleDelete
+  std::vector<std::string> get_qps = {"1"};
+  file_path = output_path + "/test-single_delete-0-qps_stats.txt";
+  CheckFileContent(get_qps, file_path, true);
+
+  // Check the top k qps prefix cut
+  std::vector<std::string> top_qps = {"At time: 0 with QPS: 1",
+                                      "The prefix: 0x64 Access count: 1"};
+  file_path =
+      output_path + "/test-single_delete-0-accessed_top_k_qps_prefix_cut.txt";
+  CheckFileContent(top_qps, file_path, true);
+}
+
+// Test analyzing of delete
+TEST_F(TraceAnalyzerTest, DeleteRange) {
+  std::string trace_path = test_path_ + "/trace";
+  std::string output_path = test_path_ + "/range_delete";
+  std::string file_path;
+  std::vector<std::string> paras = {"-analyze_range_delete"};
+  paras.push_back("-output_dir=" + output_path);
+  paras.push_back("-trace_path=" + trace_path);
+  paras.push_back("-key_space_dir=" + test_path_);
+  AnalyzeTrace(paras, output_path, trace_path);
+
+  // check the key_stats file
+  std::vector<std::string> k_stats = {"0 0 0 1 1.000000", "0 0 1 1 1.000000"};
+  file_path = output_path + "/test-range_delete-0-accessed_key_stats.txt";
+  CheckFileContent(k_stats, file_path, true);
+
+  // Check the access count distribution
+  std::vector<std::string> k_dist = {"access_count: 1 num: 2"};
+  file_path =
+      output_path + "/test-range_delete-0-accessed_key_count_distribution.txt";
+  CheckFileContent(k_dist, file_path, true);
+
+  // Check the trace sequence
+  std::vector<std::string> k_sequence = {"1", "5", "2", "3", "4",
+                                         "0", "6", "7", "0"};
+  file_path = output_path + "/test-human_readable_trace.txt";
+  CheckFileContent(k_sequence, file_path, false);
+
+  // Check the prefix
+  std::vector<std::string> k_prefix = {"0 0 0 0.000000 0.000000 0x30",
+                                       "1 1 1 1.000000 1.000000 0x65"};
+  file_path = output_path + "/test-range_delete-0-accessed_key_prefix_cut.txt";
+  CheckFileContent(k_prefix, file_path, true);
+
+  // Check the time series
+  std::vector<std::string> k_series = {"4 1533000630 0", "4 1533060100 1"};
+  file_path = output_path + "/test-range_delete-0-time_series.txt";
+  CheckFileContent(k_series, file_path, false);
+
+  // Check the accessed key in whole key space
+  std::vector<std::string> k_whole_access = {"4 1", "5 1"};
+  file_path = output_path + "/test-range_delete-0-whole_key_stats.txt";
+  CheckFileContent(k_whole_access, file_path, true);
+
+  // Check the whole key prefix cut
+  std::vector<std::string> k_whole_prefix = {"0 0x61", "1 0x62", "2 0x63",
+                                             "3 0x64", "4 0x65", "5 0x66"};
+  file_path = output_path + "/test-range_delete-0-whole_key_prefix_cut.txt";
+  CheckFileContent(k_whole_prefix, file_path, true);
+
+  // Check the overall qps
+  std::vector<std::string> all_qps = {"1 1 1 1 2 1 0 0 7"};
+  file_path = output_path + "/test-qps_stats.txt";
+  CheckFileContent(all_qps, file_path, true);
+
+  // Check the qps of DeleteRange
+  std::vector<std::string> get_qps = {"2"};
+  file_path = output_path + "/test-range_delete-0-qps_stats.txt";
+  CheckFileContent(get_qps, file_path, true);
+
+  // Check the top k qps prefix cut
+  std::vector<std::string> top_qps = {"At time: 0 with QPS: 2",
+                                      "The prefix: 0x65 Access count: 1",
+                                      "The prefix: 0x66 Access count: 1"};
+  file_path =
+      output_path + "/test-range_delete-0-accessed_top_k_qps_prefix_cut.txt";
+  CheckFileContent(top_qps, file_path, true);
+}
+
+// Test analyzing of Iterator
+TEST_F(TraceAnalyzerTest, Iterator) {
+  std::string trace_path = test_path_ + "/trace";
+  std::string output_path = test_path_ + "/iterator";
+  std::string file_path;
+  std::vector<std::string> paras = {"-analyze_iterator"};
+  paras.push_back("-output_dir=" + output_path);
+  paras.push_back("-trace_path=" + trace_path);
+  paras.push_back("-key_space_dir=" + test_path_);
+  AnalyzeTrace(paras, output_path, trace_path);
+
+  // Check the output of Seek
+  // check the key_stats file
+  std::vector<std::string> k_stats = {"0 0 0 1 1.000000"};
+  file_path = output_path + "/test-iterator_Seek-0-accessed_key_stats.txt";
+  CheckFileContent(k_stats, file_path, true);
+
+  // Check the access count distribution
+  std::vector<std::string> k_dist = {"access_count: 1 num: 1"};
+  file_path =
+      output_path + "/test-iterator_Seek-0-accessed_key_count_distribution.txt";
+  CheckFileContent(k_dist, file_path, true);
+
+  // Check the trace sequence
+  std::vector<std::string> k_sequence = {"1", "5", "2", "3", "4",
+                                         "0", "6", "7", "0"};
+  file_path = output_path + "/test-human_readable_trace.txt";
+  CheckFileContent(k_sequence, file_path, false);
+
+  // Check the prefix
+  std::vector<std::string> k_prefix = {"0 0 0 0.000000 0.000000 0x30"};
+  file_path = output_path + "/test-iterator_Seek-0-accessed_key_prefix_cut.txt";
+  CheckFileContent(k_prefix, file_path, true);
+
+  // Check the time series
+  std::vector<std::string> k_series = {"6 1 0"};
+  file_path = output_path + "/test-iterator_Seek-0-time_series.txt";
+  CheckFileContent(k_series, file_path, false);
+
+  // Check the accessed key in whole key space
+  std::vector<std::string> k_whole_access = {"0 1"};
+  file_path = output_path + "/test-iterator_Seek-0-whole_key_stats.txt";
+  CheckFileContent(k_whole_access, file_path, true);
+
+  // Check the whole key prefix cut
+  std::vector<std::string> k_whole_prefix = {"0 0x61", "1 0x62", "2 0x63",
+                                             "3 0x64", "4 0x65", "5 0x66"};
+  file_path = output_path + "/test-iterator_Seek-0-whole_key_prefix_cut.txt";
+  CheckFileContent(k_whole_prefix, file_path, true);
+
+  // Check the overall qps
+  std::vector<std::string> all_qps = {"1 1 1 1 2 1 1 1 9"};
+  file_path = output_path + "/test-qps_stats.txt";
+  CheckFileContent(all_qps, file_path, true);
+
+  // Check the qps of Iterator_Seek
+  std::vector<std::string> get_qps = {"1"};
+  file_path = output_path + "/test-iterator_Seek-0-qps_stats.txt";
+  CheckFileContent(get_qps, file_path, true);
+
+  // Check the top k qps prefix cut
+  std::vector<std::string> top_qps = {"At time: 0 with QPS: 1",
+                                      "The prefix: 0x61 Access count: 1"};
+  file_path =
+      output_path + "/test-iterator_Seek-0-accessed_top_k_qps_prefix_cut.txt";
+  CheckFileContent(top_qps, file_path, true);
+
+  // Check the output of SeekForPrev
+  // check the key_stats file
+  k_stats = {"0 0 0 1 1.000000"};
+  file_path =
+      output_path + "/test-iterator_SeekForPrev-0-accessed_key_stats.txt";
+  CheckFileContent(k_stats, file_path, true);
+
+  // Check the access count distribution
+  k_dist = {"access_count: 1 num: 1"};
+  file_path =
+      output_path +
+      "/test-iterator_SeekForPrev-0-accessed_key_count_distribution.txt";
+  CheckFileContent(k_dist, file_path, true);
+
+  // Check the prefix
+  k_prefix = {"0 0 0 0.000000 0.000000 0x30"};
+  file_path =
+      output_path + "/test-iterator_SeekForPrev-0-accessed_key_prefix_cut.txt";
+  CheckFileContent(k_prefix, file_path, true);
+
+  // Check the time series
+  k_series = {"7 0 0"};
+  file_path = output_path + "/test-iterator_SeekForPrev-0-time_series.txt";
+  CheckFileContent(k_series, file_path, false);
+
+  // Check the accessed key in whole key space
+  k_whole_access = {"1 1"};
+  file_path = output_path + "/test-iterator_SeekForPrev-0-whole_key_stats.txt";
+  CheckFileContent(k_whole_access, file_path, true);
+
+  // Check the whole key prefix cut
+  k_whole_prefix = {"0 0x61", "1 0x62", "2 0x63", "3 0x64", "4 0x65", "5 0x66"};
+  file_path =
+      output_path + "/test-iterator_SeekForPrev-0-whole_key_prefix_cut.txt";
+  CheckFileContent(k_whole_prefix, file_path, true);
+
+  // Check the qps of Iterator_SeekForPrev
+  get_qps = {"1"};
+  file_path = output_path + "/test-iterator_SeekForPrev-0-qps_stats.txt";
+  CheckFileContent(get_qps, file_path, true);
+
+  // Check the top k qps prefix cut
+  top_qps = {"At time: 0 with QPS: 1", "The prefix: 0x62 Access count: 1"};
+  file_path = output_path +
+              "/test-iterator_SeekForPrev-0-accessed_top_k_qps_prefix_cut.txt";
+  CheckFileContent(top_qps, file_path, true);
+}
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
+#endif  // GFLAG
+#else
+#include <stdio.h>
+
+int main(int /*argc*/, char** /*argv*/) {
+  fprintf(stderr, "Trace_analyzer test is not supported in ROCKSDB_LITE\n");
+  return 0;
+}
+
+#endif  // !ROCKSDB_LITE  return RUN_ALL_TESTS();
diff --git a/src/rocksdb/tools/trace_analyzer_tool.cc b/src/rocksdb/tools/trace_analyzer_tool.cc
new file mode 100644
index 00000000..a0186925
--- /dev/null
+++ b/src/rocksdb/tools/trace_analyzer_tool.cc
@@ -0,0 +1,1985 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+
+#ifndef ROCKSDB_LITE
+
+#ifndef __STDC_FORMAT_MACROS
+#define __STDC_FORMAT_MACROS
+#endif
+
+#ifdef GFLAGS
+#ifdef NUMA
+#include <numa.h>
+#include <numaif.h>
+#endif
+#ifndef OS_WIN
+#include <unistd.h>
+#endif
+
+#include <cinttypes>
+#include <cmath>
+#include <cstdio>
+#include <cstdlib>
+#include <memory>
+#include <sstream>
+#include <stdexcept>
+
+#include "db/db_impl.h"
+#include "db/memtable.h"
+#include "db/write_batch_internal.h"
+#include "options/cf_options.h"
+#include "rocksdb/db.h"
+#include "rocksdb/env.h"
+#include "rocksdb/iterator.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/slice_transform.h"
+#include "rocksdb/status.h"
+#include "rocksdb/table_properties.h"
+#include "rocksdb/utilities/ldb_cmd.h"
+#include "rocksdb/write_batch.h"
+#include "table/meta_blocks.h"
+#include "table/plain_table_factory.h"
+#include "table/table_reader.h"
+#include "tools/trace_analyzer_tool.h"
+#include "util/coding.h"
+#include "util/compression.h"
+#include "util/file_reader_writer.h"
+#include "util/gflags_compat.h"
+#include "util/random.h"
+#include "util/string_util.h"
+#include "util/trace_replay.h"
+
+using GFLAGS_NAMESPACE::ParseCommandLineFlags;
+using GFLAGS_NAMESPACE::RegisterFlagValidator;
+using GFLAGS_NAMESPACE::SetUsageMessage;
+
+DEFINE_string(trace_path, "", "The trace file path.");
+DEFINE_string(output_dir, "", "The directory to store the output files.");
+DEFINE_string(output_prefix, "trace",
+              "The prefix used for all the output files.");
+DEFINE_bool(output_key_stats, false,
+            "Output the key access count statistics to file\n"
+            "for accessed keys:\n"
+            "file name: <prefix>-<query_type>-<cf_id>-accessed_key_stats.txt\n"
+            "Format:[cf_id value_size access_keyid access_count]\n"
+            "for the whole key space keys:\n"
+            "File name: <prefix>-<query_type>-<cf_id>-whole_key_stats.txt\n"
+            "Format:[whole_key_space_keyid access_count]");
+DEFINE_bool(output_access_count_stats, false,
+            "Output the access count distribution statistics to file.\n"
+            "File name:  <prefix>-<query_type>-<cf_id>-accessed_"
+            "key_count_distribution.txt \n"
+            "Format:[access_count number_of_access_count]");
+DEFINE_bool(output_time_series, false,
+            "Output the access time in second of each key, "
+            "such that we can have the time series data of the queries \n"
+            "File name: <prefix>-<query_type>-<cf_id>-time_series.txt\n"
+            "Format:[type_id time_in_sec access_keyid].");
+DEFINE_bool(try_process_corrupted_trace, false,
+            "In default, trace_analyzer will exit if the trace file is "
+            "corrupted due to the unexpected tracing cases. If this option "
+            "is enabled, trace_analyzer will stop reading the trace file, "
+            "and start analyzing the read-in data.");
+DEFINE_int32(output_prefix_cut, 0,
+             "The number of bytes as prefix to cut the keys.\n"
+             "If it is enabled, it will generate the following:\n"
+             "For accessed keys:\n"
+             "File name: <prefix>-<query_type>-<cf_id>-"
+             "accessed_key_prefix_cut.txt \n"
+             "Format:[acessed_keyid access_count_of_prefix "
+             "number_of_keys_in_prefix average_key_access "
+             "prefix_succ_ratio prefix]\n"
+             "For whole key space keys:\n"
+             "File name: <prefix>-<query_type>-<cf_id>"
+             "-whole_key_prefix_cut.txt\n"
+             "Format:[start_keyid_in_whole_keyspace prefix]\n"
+             "if 'output_qps_stats' and 'top_k' are enabled, it will output:\n"
+             "File name: <prefix>-<query_type>-<cf_id>"
+             "-accessed_top_k_qps_prefix_cut.txt\n"
+             "Format:[the_top_ith_qps_time QPS], [prefix qps_of_this_second].");
+DEFINE_bool(convert_to_human_readable_trace, false,
+            "Convert the binary trace file to a human readable txt file "
+            "for further processing. "
+            "This file will be extremely large "
+            "(similar size as the original binary trace file). "
+            "You can specify 'no_key' to reduce the size, if key is not "
+            "needed in the next step.\n"
+            "File name: <prefix>_human_readable_trace.txt\n"
+            "Format:[type_id cf_id value_size time_in_micorsec <key>].");
+DEFINE_bool(output_qps_stats, false,
+            "Output the query per second(qps) statistics \n"
+            "For the overall qps, it will contain all qps of each query type. "
+            "The time is started from the first trace record\n"
+            "File name: <prefix>_qps_stats.txt\n"
+            "Format: [qps_type_1 qps_type_2 ...... overall_qps]\n"
+            "For each cf and query, it will have its own qps output.\n"
+            "File name: <prefix>-<query_type>-<cf_id>_qps_stats.txt \n"
+            "Format:[query_count_in_this_second].");
+DEFINE_bool(no_print, false, "Do not print out any result");
+DEFINE_string(
+    print_correlation, "",
+    "intput format: [correlation pairs][.,.]\n"
+    "Output the query correlations between the pairs of query types "
+    "listed in the parameter, input should select the operations from:\n"
+    "get, put, delete, single_delete, rangle_delete, merge. No space "
+    "between the pairs separated by commar. Example: =[get,get]... "
+    "It will print out the number of pairs of 'A after B' and "
+    "the average time interval between the two query.");
+DEFINE_string(key_space_dir, "",
+              "<the directory stores full key space files> \n"
+              "The key space files should be: <column family id>.txt");
+DEFINE_bool(analyze_get, false, "Analyze the Get query.");
+DEFINE_bool(analyze_put, false, "Analyze the Put query.");
+DEFINE_bool(analyze_delete, false, "Analyze the Delete query.");
+DEFINE_bool(analyze_single_delete, false, "Analyze the SingleDelete query.");
+DEFINE_bool(analyze_range_delete, false, "Analyze the DeleteRange query.");
+DEFINE_bool(analyze_merge, false, "Analyze the Merge query.");
+DEFINE_bool(analyze_iterator, false,
+            " Analyze the iterate query like seek() and seekForPrev().");
+DEFINE_bool(no_key, false,
+            " Does not output the key to the result files to make smaller.");
+DEFINE_bool(print_overall_stats, true,
+            " Print the stats of the whole trace, "
+            "like total requests, keys, and etc.");
+DEFINE_bool(output_key_distribution, false, "Print the key size distribution.");
+DEFINE_bool(
+    output_value_distribution, false,
+    "Out put the value size distribution, only available for Put and Merge.\n"
+    "File name: <prefix>-<query_type>-<cf_id>"
+    "-accessed_value_size_distribution.txt\n"
+    "Format:[Number_of_value_size_between x and "
+    "x+value_interval is: <the count>]");
+DEFINE_int32(print_top_k_access, 1,
+             "<top K of the variables to be printed> "
+             "Print the top k accessed keys, top k accessed prefix "
+             "and etc.");
+DEFINE_int32(output_ignore_count, 0,
+             "<threshold>, ignores the access count <= this value, "
+             "it will shorter the output.");
+DEFINE_int32(value_interval, 8,
+             "To output the value distribution, we need to set the value "
+             "intervals and make the statistic of the value size distribution "
+             "in different intervals. The default is 8.");
+DEFINE_double(sample_ratio, 1.0,
+              "If the trace size is extremely huge or user want to sample "
+              "the trace when analyzing, sample ratio can be set (0, 1.0]");
+
+namespace rocksdb {
+
+std::map<std::string, int> taOptToIndex = {
+    {"get", 0},           {"put", 1},
+    {"delete", 2},        {"single_delete", 3},
+    {"range_delete", 4},  {"merge", 5},
+    {"iterator_Seek", 6}, {"iterator_SeekForPrev", 7}};
+
+std::map<int, std::string> taIndexToOpt = {
+    {0, "get"},           {1, "put"},
+    {2, "delete"},        {3, "single_delete"},
+    {4, "range_delete"},  {5, "merge"},
+    {6, "iterator_Seek"}, {7, "iterator_SeekForPrev"}};
+
+namespace {
+
+uint64_t MultiplyCheckOverflow(uint64_t op1, uint64_t op2) {
+  if (op1 == 0 || op2 == 0) {
+    return 0;
+  }
+  if (port::kMaxUint64 / op1 < op2) {
+    return op1;
+  }
+  return (op1 * op2);
+}
+
+void DecodeCFAndKeyFromString(std::string& buffer, uint32_t* cf_id, Slice* key) {
+  Slice buf(buffer);
+  GetFixed32(&buf, cf_id);
+  GetLengthPrefixedSlice(&buf, key);
+}
+
+}  // namespace
+
+// The default constructor of AnalyzerOptions
+AnalyzerOptions::AnalyzerOptions()
+    : correlation_map(kTaTypeNum, std::vector<int>(kTaTypeNum, -1)) {}
+
+AnalyzerOptions::~AnalyzerOptions() {}
+
+void AnalyzerOptions::SparseCorrelationInput(const std::string& in_str) {
+  std::string cur = in_str;
+  if (cur.size() == 0) {
+    return;
+  }
+  while (!cur.empty()) {
+    if (cur.compare(0, 1, "[") != 0) {
+      fprintf(stderr, "Invalid correlation input: %s\n", in_str.c_str());
+      exit(1);
+    }
+    std::string opt1, opt2;
+    std::size_t split = cur.find_first_of(",");
+    if (split != std::string::npos) {
+      opt1 = cur.substr(1, split - 1);
+    } else {
+      fprintf(stderr, "Invalid correlation input: %s\n", in_str.c_str());
+      exit(1);
+    }
+    std::size_t end = cur.find_first_of("]");
+    if (end != std::string::npos) {
+      opt2 = cur.substr(split + 1, end - split - 1);
+    } else {
+      fprintf(stderr, "Invalid correlation input: %s\n", in_str.c_str());
+      exit(1);
+    }
+    cur = cur.substr(end + 1);
+
+    if (taOptToIndex.find(opt1) != taOptToIndex.end() &&
+        taOptToIndex.find(opt2) != taOptToIndex.end()) {
+      correlation_list.push_back(
+          std::make_pair(taOptToIndex[opt1], taOptToIndex[opt2]));
+    } else {
+      fprintf(stderr, "Invalid correlation input: %s\n", in_str.c_str());
+      exit(1);
+    }
+  }
+
+  int sequence = 0;
+  for (auto& it : correlation_list) {
+    correlation_map[it.first][it.second] = sequence;
+    sequence++;
+  }
+  return;
+}
+
+// The trace statistic struct constructor
+TraceStats::TraceStats() {
+  cf_id = 0;
+  cf_name = "0";
+  a_count = 0;
+  a_key_id = 0;
+  a_key_size_sqsum = 0;
+  a_key_size_sum = 0;
+  a_key_mid = 0;
+  a_value_size_sqsum = 0;
+  a_value_size_sum = 0;
+  a_value_mid = 0;
+  a_peak_qps = 0;
+  a_ave_qps = 0.0;
+}
+
+TraceStats::~TraceStats() {}
+
+// The trace analyzer constructor
+TraceAnalyzer::TraceAnalyzer(std::string& trace_path, std::string& output_path,
+                             AnalyzerOptions _analyzer_opts)
+    : trace_name_(trace_path),
+      output_path_(output_path),
+      analyzer_opts_(_analyzer_opts) {
+  rocksdb::EnvOptions env_options;
+  env_ = rocksdb::Env::Default();
+  offset_ = 0;
+  c_time_ = 0;
+  total_requests_ = 0;
+  total_access_keys_ = 0;
+  total_gets_ = 0;
+  total_writes_ = 0;
+  trace_create_time_ = 0;
+  begin_time_ = 0;
+  end_time_ = 0;
+  time_series_start_ = 0;
+  cur_time_sec_ = 0;
+  if (FLAGS_sample_ratio > 1.0 || FLAGS_sample_ratio <= 0) {
+    sample_max_ = 1;
+  } else {
+    sample_max_ = static_cast<uint32_t>(1.0 / FLAGS_sample_ratio);
+  }
+
+  ta_.resize(kTaTypeNum);
+  ta_[0].type_name = "get";
+  if (FLAGS_analyze_get) {
+    ta_[0].enabled = true;
+  } else {
+    ta_[0].enabled = false;
+  }
+  ta_[1].type_name = "put";
+  if (FLAGS_analyze_put) {
+    ta_[1].enabled = true;
+  } else {
+    ta_[1].enabled = false;
+  }
+  ta_[2].type_name = "delete";
+  if (FLAGS_analyze_delete) {
+    ta_[2].enabled = true;
+  } else {
+    ta_[2].enabled = false;
+  }
+  ta_[3].type_name = "single_delete";
+  if (FLAGS_analyze_single_delete) {
+    ta_[3].enabled = true;
+  } else {
+    ta_[3].enabled = false;
+  }
+  ta_[4].type_name = "range_delete";
+  if (FLAGS_analyze_range_delete) {
+    ta_[4].enabled = true;
+  } else {
+    ta_[4].enabled = false;
+  }
+  ta_[5].type_name = "merge";
+  if (FLAGS_analyze_merge) {
+    ta_[5].enabled = true;
+  } else {
+    ta_[5].enabled = false;
+  }
+  ta_[6].type_name = "iterator_Seek";
+  if (FLAGS_analyze_iterator) {
+    ta_[6].enabled = true;
+  } else {
+    ta_[6].enabled = false;
+  }
+  ta_[7].type_name = "iterator_SeekForPrev";
+  if (FLAGS_analyze_iterator) {
+    ta_[7].enabled = true;
+  } else {
+    ta_[7].enabled = false;
+  }
+  for (int i = 0; i < kTaTypeNum; i++) {
+    ta_[i].sample_count = 0;
+  }
+}
+
+TraceAnalyzer::~TraceAnalyzer() {}
+
+// Prepare the processing
+// Initiate the global trace reader and writer here
+Status TraceAnalyzer::PrepareProcessing() {
+  Status s;
+  // Prepare the trace reader
+  s = NewFileTraceReader(env_, env_options_, trace_name_, &trace_reader_);
+  if (!s.ok()) {
+    return s;
+  }
+
+  // Prepare and open the trace sequence file writer if needed
+  if (FLAGS_convert_to_human_readable_trace) {
+    std::string trace_sequence_name;
+    trace_sequence_name =
+        output_path_ + "/" + FLAGS_output_prefix + "-human_readable_trace.txt";
+    s = env_->NewWritableFile(trace_sequence_name, &trace_sequence_f_,
+                              env_options_);
+    if (!s.ok()) {
+      return s;
+    }
+  }
+
+  // prepare the general QPS file writer
+  if (FLAGS_output_qps_stats) {
+    std::string qps_stats_name;
+    qps_stats_name =
+        output_path_ + "/" + FLAGS_output_prefix + "-qps_stats.txt";
+    s = env_->NewWritableFile(qps_stats_name, &qps_f_, env_options_);
+    if (!s.ok()) {
+      return s;
+    }
+
+    qps_stats_name =
+        output_path_ + "/" + FLAGS_output_prefix + "-cf_qps_stats.txt";
+    s = env_->NewWritableFile(qps_stats_name, &cf_qps_f_, env_options_);
+    if (!s.ok()) {
+      return s;
+    }
+  }
+  return Status::OK();
+}
+
+Status TraceAnalyzer::ReadTraceHeader(Trace* header) {
+  assert(header != nullptr);
+  Status s = ReadTraceRecord(header);
+  if (!s.ok()) {
+    return s;
+  }
+  if (header->type != kTraceBegin) {
+    return Status::Corruption("Corrupted trace file. Incorrect header.");
+  }
+  if (header->payload.substr(0, kTraceMagic.length()) != kTraceMagic) {
+    return Status::Corruption("Corrupted trace file. Incorrect magic.");
+  }
+
+  return s;
+}
+
+Status TraceAnalyzer::ReadTraceFooter(Trace* footer) {
+  assert(footer != nullptr);
+  Status s = ReadTraceRecord(footer);
+  if (!s.ok()) {
+    return s;
+  }
+  if (footer->type != kTraceEnd) {
+    return Status::Corruption("Corrupted trace file. Incorrect footer.");
+  }
+  return s;
+}
+
+Status TraceAnalyzer::ReadTraceRecord(Trace* trace) {
+  assert(trace != nullptr);
+  std::string encoded_trace;
+  Status s = trace_reader_->Read(&encoded_trace);
+  if (!s.ok()) {
+    return s;
+  }
+
+  Slice enc_slice = Slice(encoded_trace);
+  GetFixed64(&enc_slice, &trace->ts);
+  trace->type = static_cast<TraceType>(enc_slice[0]);
+  enc_slice.remove_prefix(kTraceTypeSize + kTracePayloadLengthSize);
+  trace->payload = enc_slice.ToString();
+  return s;
+}
+
+// process the trace itself and redirect the trace content
+// to different operation type handler. With different race
+// format, this function can be changed
+Status TraceAnalyzer::StartProcessing() {
+  Status s;
+  Trace header;
+  s = ReadTraceHeader(&header);
+  if (!s.ok()) {
+    fprintf(stderr, "Cannot read the header\n");
+    return s;
+  }
+  trace_create_time_ = header.ts;
+  if (FLAGS_output_time_series) {
+    time_series_start_ = header.ts;
+  }
+
+  Trace trace;
+  while (s.ok()) {
+    trace.reset();
+    s = ReadTraceRecord(&trace);
+    if (!s.ok()) {
+      break;
+    }
+
+    total_requests_++;
+    end_time_ = trace.ts;
+    if (trace.type == kTraceWrite) {
+      total_writes_++;
+      c_time_ = trace.ts;
+      WriteBatch batch(trace.payload);
+
+      // Note that, if the write happens in a transaction,
+      // 'Write' will be called twice, one for Prepare, one for
+      // Commit. Thus, in the trace, for the same WriteBatch, there
+      // will be two reords if it is in a transaction. Here, we only
+      // process the reord that is committed. If write is non-transaction,
+      // HasBeginPrepare()==false, so we process it normally.
+      if (batch.HasBeginPrepare() && !batch.HasCommit()) {
+        continue;
+      }
+      TraceWriteHandler write_handler(this);
+      s = batch.Iterate(&write_handler);
+      if (!s.ok()) {
+        fprintf(stderr, "Cannot process the write batch in the trace\n");
+        return s;
+      }
+    } else if (trace.type == kTraceGet) {
+      uint32_t cf_id = 0;
+      Slice key;
+      DecodeCFAndKeyFromString(trace.payload, &cf_id, &key);
+      total_gets_++;
+
+      s = HandleGet(cf_id, key.ToString(), trace.ts, 1);
+      if (!s.ok()) {
+        fprintf(stderr, "Cannot process the get in the trace\n");
+        return s;
+      }
+    } else if (trace.type == kTraceIteratorSeek ||
+               trace.type == kTraceIteratorSeekForPrev) {
+      uint32_t cf_id = 0;
+      Slice key;
+      DecodeCFAndKeyFromString(trace.payload, &cf_id, &key);
+      s = HandleIter(cf_id, key.ToString(), trace.ts, trace.type);
+      if (!s.ok()) {
+        fprintf(stderr, "Cannot process the iterator in the trace\n");
+        return s;
+      }
+    } else if (trace.type == kTraceEnd) {
+      break;
+    }
+  }
+  if (s.IsIncomplete()) {
+    // Fix it: Reaching eof returns Incomplete status at the moment.
+    //
+    return Status::OK();
+  }
+  return s;
+}
+
+// After the trace is processed by StartProcessing, the statistic data
+// is stored in the map or other in memory data structures. To get the
+// other statistic result such as key size distribution, value size
+// distribution, these data structures are re-processed here.
+Status TraceAnalyzer::MakeStatistics() {
+  int ret;
+  Status s;
+  for (int type = 0; type < kTaTypeNum; type++) {
+    if (!ta_[type].enabled) {
+      continue;
+    }
+    for (auto& stat : ta_[type].stats) {
+      stat.second.a_key_id = 0;
+      for (auto& record : stat.second.a_key_stats) {
+        record.second.key_id = stat.second.a_key_id;
+        stat.second.a_key_id++;
+        if (record.second.access_count <=
+            static_cast<uint64_t>(FLAGS_output_ignore_count)) {
+          continue;
+        }
+
+        // Generate the key access count distribution data
+        if (FLAGS_output_access_count_stats) {
+          if (stat.second.a_count_stats.find(record.second.access_count) ==
+              stat.second.a_count_stats.end()) {
+            stat.second.a_count_stats[record.second.access_count] = 1;
+          } else {
+            stat.second.a_count_stats[record.second.access_count]++;
+          }
+        }
+
+        // Generate the key size distribution data
+        if (FLAGS_output_key_distribution) {
+          if (stat.second.a_key_size_stats.find(record.first.size()) ==
+              stat.second.a_key_size_stats.end()) {
+            stat.second.a_key_size_stats[record.first.size()] = 1;
+          } else {
+            stat.second.a_key_size_stats[record.first.size()]++;
+          }
+        }
+
+        if (!FLAGS_print_correlation.empty()) {
+          s = MakeStatisticCorrelation(stat.second, record.second);
+          if (!s.ok()) {
+            return s;
+          }
+        }
+      }
+
+      // Output the prefix cut or the whole content of the accessed key space
+      if (FLAGS_output_key_stats || FLAGS_output_prefix_cut > 0) {
+        s = MakeStatisticKeyStatsOrPrefix(stat.second);
+        if (!s.ok()) {
+          return s;
+        }
+      }
+
+      // output the access count distribution
+      if (FLAGS_output_access_count_stats && stat.second.a_count_dist_f) {
+        for (auto& record : stat.second.a_count_stats) {
+          ret = sprintf(buffer_, "access_count: %" PRIu64 " num: %" PRIu64 "\n",
+                        record.first, record.second);
+          if (ret < 0) {
+            return Status::IOError("Format the output failed");
+          }
+          std::string printout(buffer_);
+          s = stat.second.a_count_dist_f->Append(printout);
+          if (!s.ok()) {
+            fprintf(stderr, "Write access count distribution file failed\n");
+            return s;
+          }
+        }
+      }
+
+      // find the medium of the key size
+      uint64_t k_count = 0;
+      bool get_mid = false;
+      for (auto& record : stat.second.a_key_size_stats) {
+        k_count += record.second;
+        if (!get_mid && k_count >= stat.second.a_key_mid) {
+          stat.second.a_key_mid = record.first;
+          get_mid = true;
+        }
+        if (FLAGS_output_key_distribution && stat.second.a_key_size_f) {
+          ret = sprintf(buffer_, "%" PRIu64 " %" PRIu64 "\n", record.first,
+                        record.second);
+          if (ret < 0) {
+            return Status::IOError("Format output failed");
+          }
+          std::string printout(buffer_);
+          s = stat.second.a_key_size_f->Append(printout);
+          if (!s.ok()) {
+            fprintf(stderr, "Write key size distribution file failed\n");
+            return s;
+          }
+        }
+      }
+
+      // output the value size distribution
+      uint64_t v_begin = 0, v_end = 0, v_count = 0;
+      get_mid = false;
+      for (auto& record : stat.second.a_value_size_stats) {
+        v_begin = v_end;
+        v_end = (record.first + 1) * FLAGS_value_interval;
+        v_count += record.second;
+        if (!get_mid && v_count >= stat.second.a_count / 2) {
+          stat.second.a_value_mid = (v_begin + v_end) / 2;
+          get_mid = true;
+        }
+        if (FLAGS_output_value_distribution && stat.second.a_value_size_f &&
+            (type == TraceOperationType::kPut ||
+             type == TraceOperationType::kMerge)) {
+          ret = sprintf(buffer_,
+                        "Number_of_value_size_between %" PRIu64 " and %" PRIu64
+                        " is: %" PRIu64 "\n",
+                        v_begin, v_end, record.second);
+          if (ret < 0) {
+            return Status::IOError("Format output failed");
+          }
+          std::string printout(buffer_);
+          s = stat.second.a_value_size_f->Append(printout);
+          if (!s.ok()) {
+            fprintf(stderr, "Write value size distribution file failed\n");
+            return s;
+          }
+        }
+      }
+    }
+  }
+
+  // Make the QPS statistics
+  if (FLAGS_output_qps_stats) {
+    s = MakeStatisticQPS();
+    if (!s.ok()) {
+      return s;
+    }
+  }
+
+  return Status::OK();
+}
+
+// Process the statistics of the key access and
+// prefix of the accessed keys if required
+Status TraceAnalyzer::MakeStatisticKeyStatsOrPrefix(TraceStats& stats) {
+  int ret;
+  Status s;
+  std::string prefix = "0";
+  uint64_t prefix_access = 0;
+  uint64_t prefix_count = 0;
+  uint64_t prefix_succ_access = 0;
+  double prefix_ave_access = 0.0;
+  stats.a_succ_count = 0;
+  for (auto& record : stats.a_key_stats) {
+    // write the key access statistic file
+    if (!stats.a_key_f) {
+      return Status::IOError("Failed to open accessed_key_stats file.");
+    }
+    stats.a_succ_count += record.second.succ_count;
+    double succ_ratio = 0.0;
+    if (record.second.access_count > 0) {
+      succ_ratio = (static_cast<double>(record.second.succ_count)) /
+                   record.second.access_count;
+    }
+    ret = sprintf(buffer_, "%u %zu %" PRIu64 " %" PRIu64 " %f\n",
+                  record.second.cf_id, record.second.value_size,
+                  record.second.key_id, record.second.access_count, succ_ratio);
+    if (ret < 0) {
+      return Status::IOError("Format output failed");
+    }
+    std::string printout(buffer_);
+    s = stats.a_key_f->Append(printout);
+    if (!s.ok()) {
+      fprintf(stderr, "Write key access file failed\n");
+      return s;
+    }
+
+    // write the prefix cut of the accessed keys
+    if (FLAGS_output_prefix_cut > 0 && stats.a_prefix_cut_f) {
+      if (record.first.compare(0, FLAGS_output_prefix_cut, prefix) != 0) {
+        std::string prefix_out = rocksdb::LDBCommand::StringToHex(prefix);
+        if (prefix_count == 0) {
+          prefix_ave_access = 0.0;
+        } else {
+          prefix_ave_access =
+              (static_cast<double>(prefix_access)) / prefix_count;
+        }
+        double prefix_succ_ratio = 0.0;
+        if (prefix_access > 0) {
+          prefix_succ_ratio =
+              (static_cast<double>(prefix_succ_access)) / prefix_access;
+        }
+        ret = sprintf(buffer_, "%" PRIu64 " %" PRIu64 " %" PRIu64 " %f %f %s\n",
+                      record.second.key_id, prefix_access, prefix_count,
+                      prefix_ave_access, prefix_succ_ratio, prefix_out.c_str());
+        if (ret < 0) {
+          return Status::IOError("Format output failed");
+        }
+        std::string pout(buffer_);
+        s = stats.a_prefix_cut_f->Append(pout);
+        if (!s.ok()) {
+          fprintf(stderr, "Write accessed key prefix file failed\n");
+          return s;
+        }
+
+        // make the top k statistic for the prefix
+        if (static_cast<int32_t>(stats.top_k_prefix_access.size()) <
+            FLAGS_print_top_k_access) {
+          stats.top_k_prefix_access.push(
+              std::make_pair(prefix_access, prefix_out));
+        } else {
+          if (prefix_access > stats.top_k_prefix_access.top().first) {
+            stats.top_k_prefix_access.pop();
+            stats.top_k_prefix_access.push(
+                std::make_pair(prefix_access, prefix_out));
+          }
+        }
+
+        if (static_cast<int32_t>(stats.top_k_prefix_ave.size()) <
+            FLAGS_print_top_k_access) {
+          stats.top_k_prefix_ave.push(
+              std::make_pair(prefix_ave_access, prefix_out));
+        } else {
+          if (prefix_ave_access > stats.top_k_prefix_ave.top().first) {
+            stats.top_k_prefix_ave.pop();
+            stats.top_k_prefix_ave.push(
+                std::make_pair(prefix_ave_access, prefix_out));
+          }
+        }
+
+        prefix = record.first.substr(0, FLAGS_output_prefix_cut);
+        prefix_access = 0;
+        prefix_count = 0;
+        prefix_succ_access = 0;
+      }
+      prefix_access += record.second.access_count;
+      prefix_count += 1;
+      prefix_succ_access += record.second.succ_count;
+    }
+  }
+  return Status::OK();
+}
+
+// Process the statistics of different query type
+// correlations
+Status TraceAnalyzer::MakeStatisticCorrelation(TraceStats& stats,
+                                               StatsUnit& unit) {
+  if (stats.correlation_output.size() !=
+      analyzer_opts_.correlation_list.size()) {
+    return Status::Corruption("Cannot make the statistic of correlation.");
+  }
+
+  for (int i = 0; i < static_cast<int>(analyzer_opts_.correlation_list.size());
+       i++) {
+    if (i >= static_cast<int>(stats.correlation_output.size()) ||
+        i >= static_cast<int>(unit.v_correlation.size())) {
+      break;
+    }
+    stats.correlation_output[i].first += unit.v_correlation[i].count;
+    stats.correlation_output[i].second += unit.v_correlation[i].total_ts;
+  }
+  return Status::OK();
+}
+
+// Process the statistics of QPS
+Status TraceAnalyzer::MakeStatisticQPS() {
+  if(begin_time_ == 0) {
+    begin_time_ = trace_create_time_;
+  }
+  uint32_t duration =
+      static_cast<uint32_t>((end_time_ - begin_time_) / 1000000);
+  int ret;
+  Status s;
+  std::vector<std::vector<uint32_t>> type_qps(
+      duration, std::vector<uint32_t>(kTaTypeNum + 1, 0));
+  std::vector<uint64_t> qps_sum(kTaTypeNum + 1, 0);
+  std::vector<uint32_t> qps_peak(kTaTypeNum + 1, 0);
+  qps_ave_.resize(kTaTypeNum + 1);
+
+  for (int type = 0; type < kTaTypeNum; type++) {
+    if (!ta_[type].enabled) {
+      continue;
+    }
+    for (auto& stat : ta_[type].stats) {
+      uint32_t time_line = 0;
+      uint64_t cf_qps_sum = 0;
+      for (auto& time_it : stat.second.a_qps_stats) {
+        if (time_it.first >= duration) {
+          continue;
+        }
+        type_qps[time_it.first][kTaTypeNum] += time_it.second;
+        type_qps[time_it.first][type] += time_it.second;
+        cf_qps_sum += time_it.second;
+        if (time_it.second > stat.second.a_peak_qps) {
+          stat.second.a_peak_qps = time_it.second;
+        }
+        if (stat.second.a_qps_f) {
+          while (time_line < time_it.first) {
+            ret = sprintf(buffer_, "%u\n", 0);
+            if (ret < 0) {
+              return Status::IOError("Format the output failed");
+            }
+            std::string printout(buffer_);
+            s = stat.second.a_qps_f->Append(printout);
+            if (!s.ok()) {
+              fprintf(stderr, "Write QPS file failed\n");
+              return s;
+            }
+            time_line++;
+          }
+          ret = sprintf(buffer_, "%u\n", time_it.second);
+          if (ret < 0) {
+            return Status::IOError("Format the output failed");
+          }
+          std::string printout(buffer_);
+          s = stat.second.a_qps_f->Append(printout);
+          if (!s.ok()) {
+            fprintf(stderr, "Write QPS file failed\n");
+            return s;
+          }
+          if (time_line == time_it.first) {
+            time_line++;
+          }
+        }
+
+        // Process the top k QPS peaks
+        if (FLAGS_output_prefix_cut > 0) {
+          if (static_cast<int32_t>(stat.second.top_k_qps_sec.size()) <
+              FLAGS_print_top_k_access) {
+            stat.second.top_k_qps_sec.push(
+                std::make_pair(time_it.second, time_it.first));
+          } else {
+            if (stat.second.top_k_qps_sec.size() > 0 &&
+                stat.second.top_k_qps_sec.top().first < time_it.second) {
+              stat.second.top_k_qps_sec.pop();
+              stat.second.top_k_qps_sec.push(
+                  std::make_pair(time_it.second, time_it.first));
+            }
+          }
+        }
+      }
+      if (duration == 0) {
+        stat.second.a_ave_qps = 0;
+      } else {
+        stat.second.a_ave_qps = (static_cast<double>(cf_qps_sum)) / duration;
+      }
+
+      // Output the accessed unique key number change overtime
+      if (stat.second.a_key_num_f) {
+        uint64_t cur_uni_key =
+            static_cast<uint64_t>(stat.second.a_key_stats.size());
+        double cur_ratio = 0.0;
+        uint64_t cur_num = 0;
+        for (uint32_t i = 0; i < duration; i++) {
+          auto find_time = stat.second.uni_key_num.find(i);
+          if (find_time != stat.second.uni_key_num.end()) {
+            cur_ratio = (static_cast<double>(find_time->second)) / cur_uni_key;
+            cur_num = find_time->second;
+          }
+          ret = sprintf(buffer_, "%" PRIu64 " %.12f\n", cur_num, cur_ratio);
+          if (ret < 0) {
+            return Status::IOError("Format the output failed");
+          }
+          std::string printout(buffer_);
+          s = stat.second.a_key_num_f->Append(printout);
+          if (!s.ok()) {
+            fprintf(stderr,
+                    "Write accessed unique key number change file failed\n");
+            return s;
+          }
+        }
+      }
+
+      // output the prefix of top k access peak
+      if (FLAGS_output_prefix_cut > 0 && stat.second.a_top_qps_prefix_f) {
+        while (!stat.second.top_k_qps_sec.empty()) {
+          ret = sprintf(buffer_, "At time: %u with QPS: %u\n",
+                        stat.second.top_k_qps_sec.top().second,
+                        stat.second.top_k_qps_sec.top().first);
+          if (ret < 0) {
+            return Status::IOError("Format the output failed");
+          }
+          std::string printout(buffer_);
+          s = stat.second.a_top_qps_prefix_f->Append(printout);
+          if (!s.ok()) {
+            fprintf(stderr, "Write prefix QPS top K file failed\n");
+            return s;
+          }
+          uint32_t qps_time = stat.second.top_k_qps_sec.top().second;
+          stat.second.top_k_qps_sec.pop();
+          if (stat.second.a_qps_prefix_stats.find(qps_time) !=
+              stat.second.a_qps_prefix_stats.end()) {
+            for (auto& qps_prefix : stat.second.a_qps_prefix_stats[qps_time]) {
+              std::string qps_prefix_out =
+                  rocksdb::LDBCommand::StringToHex(qps_prefix.first);
+              ret = sprintf(buffer_, "The prefix: %s Access count: %u\n",
+                            qps_prefix_out.c_str(), qps_prefix.second);
+              if (ret < 0) {
+                return Status::IOError("Format the output failed");
+              }
+              std::string pout(buffer_);
+              s = stat.second.a_top_qps_prefix_f->Append(pout);
+              if (!s.ok()) {
+                fprintf(stderr, "Write prefix QPS top K file failed\n");
+                return s;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  if (qps_f_) {
+    for (uint32_t i = 0; i < duration; i++) {
+      for (int type = 0; type <= kTaTypeNum; type++) {
+        if (type < kTaTypeNum) {
+          ret = sprintf(buffer_, "%u ", type_qps[i][type]);
+        } else {
+          ret = sprintf(buffer_, "%u\n", type_qps[i][type]);
+        }
+        if (ret < 0) {
+          return Status::IOError("Format the output failed");
+        }
+        std::string printout(buffer_);
+        s = qps_f_->Append(printout);
+        if (!s.ok()) {
+          return s;
+        }
+        qps_sum[type] += type_qps[i][type];
+        if (type_qps[i][type] > qps_peak[type]) {
+          qps_peak[type] = type_qps[i][type];
+        }
+      }
+    }
+  }
+
+  if (cf_qps_f_) {
+    int cfs_size = static_cast<uint32_t>(cfs_.size());
+    uint32_t v;
+    for (uint32_t i = 0; i < duration; i++) {
+      for (int cf = 0; cf < cfs_size; cf++) {
+        if (cfs_[cf].cf_qps.find(i) != cfs_[cf].cf_qps.end()) {
+          v = cfs_[cf].cf_qps[i];
+        } else {
+          v = 0;
+        }
+        if (cf < cfs_size - 1) {
+          ret = sprintf(buffer_, "%u ", v);
+        } else {
+          ret = sprintf(buffer_, "%u\n", v);
+        }
+        if (ret < 0) {
+          return Status::IOError("Format the output failed");
+        }
+        std::string printout(buffer_);
+        s = cf_qps_f_->Append(printout);
+        if (!s.ok()) {
+          return s;
+        }
+      }
+    }
+  }
+
+  qps_peak_ = qps_peak;
+  for (int type = 0; type <= kTaTypeNum; type++) {
+    if (duration == 0) {
+      qps_ave_[type] = 0;
+    } else {
+      qps_ave_[type] = (static_cast<double>(qps_sum[type])) / duration;
+    }
+  }
+
+  return Status::OK();
+}
+
+// In reprocessing, if we have the whole key space
+// we can output the access count of all keys in a cf
+// we can make some statistics of the whole key space
+// also, we output the top k accessed keys here
+Status TraceAnalyzer::ReProcessing() {
+  int ret;
+  Status s;
+  for (auto& cf_it : cfs_) {
+    uint32_t cf_id = cf_it.first;
+
+    // output the time series;
+    if (FLAGS_output_time_series) {
+      for (int type = 0; type < kTaTypeNum; type++) {
+        if (!ta_[type].enabled ||
+            ta_[type].stats.find(cf_id) == ta_[type].stats.end()) {
+          continue;
+        }
+        TraceStats& stat = ta_[type].stats[cf_id];
+        if (!stat.time_series_f) {
+          fprintf(stderr, "Cannot write time_series of '%s' in '%u'\n",
+                  ta_[type].type_name.c_str(), cf_id);
+          continue;
+        }
+        while (!stat.time_series.empty()) {
+          uint64_t key_id = 0;
+          auto found = stat.a_key_stats.find(stat.time_series.front().key);
+          if (found != stat.a_key_stats.end()) {
+            key_id = found->second.key_id;
+          }
+          ret = sprintf(buffer_, "%u %" PRIu64 " %" PRIu64 "\n",
+                        stat.time_series.front().type,
+                        stat.time_series.front().ts, key_id);
+          if (ret < 0) {
+            return Status::IOError("Format the output failed");
+          }
+          std::string printout(buffer_);
+          s = stat.time_series_f->Append(printout);
+          if (!s.ok()) {
+            fprintf(stderr, "Write time series file failed\n");
+            return s;
+          }
+          stat.time_series.pop_front();
+        }
+      }
+    }
+
+    // process the whole key space if needed
+    if (!FLAGS_key_space_dir.empty()) {
+      std::string whole_key_path =
+          FLAGS_key_space_dir + "/" + std::to_string(cf_id) + ".txt";
+      std::string input_key, get_key;
+      std::vector<std::string> prefix(kTaTypeNum);
+      std::istringstream iss;
+      bool has_data = true;
+      s = env_->NewSequentialFile(whole_key_path, &wkey_input_f_, env_options_);
+      if (!s.ok()) {
+        fprintf(stderr, "Cannot open the whole key space file of CF: %u\n",
+                cf_id);
+        wkey_input_f_.reset();
+      }
+      if (wkey_input_f_) {
+        for (cfs_[cf_id].w_count = 0;
+             ReadOneLine(&iss, wkey_input_f_.get(), &get_key, &has_data, &s);
+             ++cfs_[cf_id].w_count) {
+          if (!s.ok()) {
+            fprintf(stderr, "Read whole key space file failed\n");
+            return s;
+          }
+
+          input_key = rocksdb::LDBCommand::HexToString(get_key);
+          for (int type = 0; type < kTaTypeNum; type++) {
+            if (!ta_[type].enabled) {
+              continue;
+            }
+            TraceStats& stat = ta_[type].stats[cf_id];
+            if (stat.w_key_f) {
+              if (stat.a_key_stats.find(input_key) != stat.a_key_stats.end()) {
+                ret = sprintf(buffer_, "%" PRIu64 " %" PRIu64 "\n",
+                              cfs_[cf_id].w_count,
+                              stat.a_key_stats[input_key].access_count);
+                if (ret < 0) {
+                  return Status::IOError("Format the output failed");
+                }
+                std::string printout(buffer_);
+                s = stat.w_key_f->Append(printout);
+                if (!s.ok()) {
+                  fprintf(stderr, "Write whole key space access file failed\n");
+                  return s;
+                }
+              }
+            }
+
+            // Output the prefix cut file of the whole key space
+            if (FLAGS_output_prefix_cut > 0 && stat.w_prefix_cut_f) {
+              if (input_key.compare(0, FLAGS_output_prefix_cut, prefix[type]) !=
+                  0) {
+                prefix[type] = input_key.substr(0, FLAGS_output_prefix_cut);
+                std::string prefix_out =
+                    rocksdb::LDBCommand::StringToHex(prefix[type]);
+                ret = sprintf(buffer_, "%" PRIu64 " %s\n", cfs_[cf_id].w_count,
+                              prefix_out.c_str());
+                if (ret < 0) {
+                  return Status::IOError("Format the output failed");
+                }
+                std::string printout(buffer_);
+                s = stat.w_prefix_cut_f->Append(printout);
+                if (!s.ok()) {
+                  fprintf(stderr,
+                          "Write whole key space prefix cut file failed\n");
+                  return s;
+                }
+              }
+            }
+          }
+
+          // Make the statistics fo the key size distribution
+          if (FLAGS_output_key_distribution) {
+            if (cfs_[cf_id].w_key_size_stats.find(input_key.size()) ==
+                cfs_[cf_id].w_key_size_stats.end()) {
+              cfs_[cf_id].w_key_size_stats[input_key.size()] = 1;
+            } else {
+              cfs_[cf_id].w_key_size_stats[input_key.size()]++;
+            }
+          }
+        }
+      }
+    }
+
+    // process the top k accessed keys
+    if (FLAGS_print_top_k_access > 0) {
+      for (int type = 0; type < kTaTypeNum; type++) {
+        if (!ta_[type].enabled ||
+            ta_[type].stats.find(cf_id) == ta_[type].stats.end()) {
+          continue;
+        }
+        TraceStats& stat = ta_[type].stats[cf_id];
+        for (auto& record : stat.a_key_stats) {
+          if (static_cast<int32_t>(stat.top_k_queue.size()) <
+              FLAGS_print_top_k_access) {
+            stat.top_k_queue.push(
+                std::make_pair(record.second.access_count, record.first));
+          } else {
+            if (record.second.access_count > stat.top_k_queue.top().first) {
+              stat.top_k_queue.pop();
+              stat.top_k_queue.push(
+                  std::make_pair(record.second.access_count, record.first));
+            }
+          }
+        }
+      }
+    }
+  }
+  return Status::OK();
+}
+
+// End the processing, print the requested results
+Status TraceAnalyzer::EndProcessing() {
+  if (trace_sequence_f_) {
+    trace_sequence_f_->Close();
+  }
+  if (FLAGS_no_print) {
+    return Status::OK();
+  }
+  PrintStatistics();
+  CloseOutputFiles();
+  return Status::OK();
+}
+
+// Insert the corresponding key statistics to the correct type
+// and correct CF, output the time-series file if needed
+Status TraceAnalyzer::KeyStatsInsertion(const uint32_t& type,
+                                        const uint32_t& cf_id,
+                                        const std::string& key,
+                                        const size_t value_size,
+                                        const uint64_t ts) {
+  Status s;
+  StatsUnit unit;
+  unit.key_id = 0;
+  unit.cf_id = cf_id;
+  unit.value_size = value_size;
+  unit.access_count = 1;
+  unit.latest_ts = ts;
+  if (type != TraceOperationType::kGet || value_size > 0) {
+    unit.succ_count = 1;
+  } else {
+    unit.succ_count = 0;
+  }
+  unit.v_correlation.resize(analyzer_opts_.correlation_list.size());
+  for (int i = 0;
+       i < (static_cast<int>(analyzer_opts_.correlation_list.size())); i++) {
+    unit.v_correlation[i].count = 0;
+    unit.v_correlation[i].total_ts = 0;
+  }
+  std::string prefix;
+  if (FLAGS_output_prefix_cut > 0) {
+    prefix = key.substr(0, FLAGS_output_prefix_cut);
+  }
+
+  if (begin_time_ == 0) {
+    begin_time_ = ts;
+  }
+  uint32_t time_in_sec;
+  if (ts < begin_time_) {
+    time_in_sec = 0;
+  } else {
+    time_in_sec = static_cast<uint32_t>((ts - begin_time_) / 1000000);
+  }
+
+  uint64_t dist_value_size = value_size / FLAGS_value_interval;
+  auto found_stats = ta_[type].stats.find(cf_id);
+  if (found_stats == ta_[type].stats.end()) {
+    ta_[type].stats[cf_id].cf_id = cf_id;
+    ta_[type].stats[cf_id].cf_name = std::to_string(cf_id);
+    ta_[type].stats[cf_id].a_count = 1;
+    ta_[type].stats[cf_id].a_key_id = 0;
+    ta_[type].stats[cf_id].a_key_size_sqsum = MultiplyCheckOverflow(
+        static_cast<uint64_t>(key.size()), static_cast<uint64_t>(key.size()));
+    ta_[type].stats[cf_id].a_key_size_sum = key.size();
+    ta_[type].stats[cf_id].a_value_size_sqsum = MultiplyCheckOverflow(
+        static_cast<uint64_t>(value_size), static_cast<uint64_t>(value_size));
+    ta_[type].stats[cf_id].a_value_size_sum = value_size;
+    s = OpenStatsOutputFiles(ta_[type].type_name, ta_[type].stats[cf_id]);
+    if (!FLAGS_print_correlation.empty()) {
+      s = StatsUnitCorrelationUpdate(unit, type, ts, key);
+    }
+    ta_[type].stats[cf_id].a_key_stats[key] = unit;
+    ta_[type].stats[cf_id].a_value_size_stats[dist_value_size] = 1;
+    ta_[type].stats[cf_id].a_qps_stats[time_in_sec] = 1;
+    ta_[type].stats[cf_id].correlation_output.resize(
+        analyzer_opts_.correlation_list.size());
+    if (FLAGS_output_prefix_cut > 0) {
+      std::map<std::string, uint32_t> tmp_qps_map;
+      tmp_qps_map[prefix] = 1;
+      ta_[type].stats[cf_id].a_qps_prefix_stats[time_in_sec] = tmp_qps_map;
+    }
+    if (time_in_sec != cur_time_sec_) {
+      ta_[type].stats[cf_id].uni_key_num[cur_time_sec_] =
+          static_cast<uint64_t>(ta_[type].stats[cf_id].a_key_stats.size());
+      cur_time_sec_ = time_in_sec;
+    }
+  } else {
+    found_stats->second.a_count++;
+    found_stats->second.a_key_size_sqsum += MultiplyCheckOverflow(
+        static_cast<uint64_t>(key.size()), static_cast<uint64_t>(key.size()));
+    found_stats->second.a_key_size_sum += key.size();
+    found_stats->second.a_value_size_sqsum += MultiplyCheckOverflow(
+        static_cast<uint64_t>(value_size), static_cast<uint64_t>(value_size));
+    found_stats->second.a_value_size_sum += value_size;
+    auto found_key = found_stats->second.a_key_stats.find(key);
+    if (found_key == found_stats->second.a_key_stats.end()) {
+      found_stats->second.a_key_stats[key] = unit;
+    } else {
+      found_key->second.access_count++;
+      if (type != TraceOperationType::kGet || value_size > 0) {
+        found_key->second.succ_count++;
+      }
+      if (!FLAGS_print_correlation.empty()) {
+        s = StatsUnitCorrelationUpdate(found_key->second, type, ts, key);
+      }
+    }
+    if (time_in_sec != cur_time_sec_) {
+      found_stats->second.uni_key_num[cur_time_sec_] =
+          static_cast<uint64_t>(found_stats->second.a_key_stats.size());
+      cur_time_sec_ = time_in_sec;
+    }
+
+    auto found_value =
+        found_stats->second.a_value_size_stats.find(dist_value_size);
+    if (found_value == found_stats->second.a_value_size_stats.end()) {
+      found_stats->second.a_value_size_stats[dist_value_size] = 1;
+    } else {
+      found_value->second++;
+    }
+
+    auto found_qps = found_stats->second.a_qps_stats.find(time_in_sec);
+    if (found_qps == found_stats->second.a_qps_stats.end()) {
+      found_stats->second.a_qps_stats[time_in_sec] = 1;
+    } else {
+      found_qps->second++;
+    }
+
+    if (FLAGS_output_prefix_cut > 0) {
+      auto found_qps_prefix =
+          found_stats->second.a_qps_prefix_stats.find(time_in_sec);
+      if (found_qps_prefix == found_stats->second.a_qps_prefix_stats.end()) {
+        std::map<std::string, uint32_t> tmp_qps_map;
+        found_stats->second.a_qps_prefix_stats[time_in_sec] = tmp_qps_map;
+      }
+      if (found_stats->second.a_qps_prefix_stats[time_in_sec].find(prefix) ==
+          found_stats->second.a_qps_prefix_stats[time_in_sec].end()) {
+        found_stats->second.a_qps_prefix_stats[time_in_sec][prefix] = 1;
+      } else {
+        found_stats->second.a_qps_prefix_stats[time_in_sec][prefix]++;
+      }
+    }
+  }
+
+  if (cfs_.find(cf_id) == cfs_.end()) {
+    CfUnit cf_unit;
+    cf_unit.cf_id = cf_id;
+    cf_unit.w_count = 0;
+    cf_unit.a_count = 0;
+    cfs_[cf_id] = cf_unit;
+  }
+
+  if (FLAGS_output_qps_stats) {
+    cfs_[cf_id].cf_qps[time_in_sec]++;
+  }
+
+  if (FLAGS_output_time_series) {
+    TraceUnit trace_u;
+    trace_u.type = type;
+    trace_u.key = key;
+    trace_u.value_size = value_size;
+    trace_u.ts = (ts - time_series_start_) / 1000000;
+    trace_u.cf_id = cf_id;
+    ta_[type].stats[cf_id].time_series.push_back(trace_u);
+  }
+
+  return Status::OK();
+}
+
+// Update the correlation unit of each key if enabled
+Status TraceAnalyzer::StatsUnitCorrelationUpdate(StatsUnit& unit,
+                                                 const uint32_t& type_second,
+                                                 const uint64_t& ts,
+                                                 const std::string& key) {
+  if (type_second >= kTaTypeNum) {
+    fprintf(stderr, "Unknown Type Id: %u\n", type_second);
+    return Status::NotFound();
+  }
+
+  for (int type_first = 0; type_first < kTaTypeNum; type_first++) {
+    if (type_first >= static_cast<int>(ta_.size()) ||
+        type_first >= static_cast<int>(analyzer_opts_.correlation_map.size())) {
+      break;
+    }
+    if (analyzer_opts_.correlation_map[type_first][type_second] < 0 ||
+        ta_[type_first].stats.find(unit.cf_id) == ta_[type_first].stats.end() ||
+        ta_[type_first].stats[unit.cf_id].a_key_stats.find(key) ==
+            ta_[type_first].stats[unit.cf_id].a_key_stats.end() ||
+        ta_[type_first].stats[unit.cf_id].a_key_stats[key].latest_ts == ts) {
+      continue;
+    }
+
+    int correlation_id =
+        analyzer_opts_.correlation_map[type_first][type_second];
+
+    // after get the x-y operation time or x, update;
+    if (correlation_id < 0 ||
+        correlation_id >= static_cast<int>(unit.v_correlation.size())) {
+      continue;
+    }
+    unit.v_correlation[correlation_id].count++;
+    unit.v_correlation[correlation_id].total_ts +=
+        (ts - ta_[type_first].stats[unit.cf_id].a_key_stats[key].latest_ts);
+  }
+
+  unit.latest_ts = ts;
+  return Status::OK();
+}
+
+// when a new trace statistic is created, the file handler
+// pointers should be initiated if needed according to
+// the trace analyzer options
+Status TraceAnalyzer::OpenStatsOutputFiles(const std::string& type,
+                                           TraceStats& new_stats) {
+  Status s;
+  if (FLAGS_output_key_stats) {
+    s = CreateOutputFile(type, new_stats.cf_name, "accessed_key_stats.txt",
+                         &new_stats.a_key_f);
+    s = CreateOutputFile(type, new_stats.cf_name,
+                         "accessed_unique_key_num_change.txt",
+                         &new_stats.a_key_num_f);
+    if (!FLAGS_key_space_dir.empty()) {
+      s = CreateOutputFile(type, new_stats.cf_name, "whole_key_stats.txt",
+                           &new_stats.w_key_f);
+    }
+  }
+
+  if (FLAGS_output_access_count_stats) {
+    s = CreateOutputFile(type, new_stats.cf_name,
+                         "accessed_key_count_distribution.txt",
+                         &new_stats.a_count_dist_f);
+  }
+
+  if (FLAGS_output_prefix_cut > 0) {
+    s = CreateOutputFile(type, new_stats.cf_name, "accessed_key_prefix_cut.txt",
+                         &new_stats.a_prefix_cut_f);
+    if (!FLAGS_key_space_dir.empty()) {
+      s = CreateOutputFile(type, new_stats.cf_name, "whole_key_prefix_cut.txt",
+                           &new_stats.w_prefix_cut_f);
+    }
+
+    if (FLAGS_output_qps_stats) {
+      s = CreateOutputFile(type, new_stats.cf_name,
+                           "accessed_top_k_qps_prefix_cut.txt",
+                           &new_stats.a_top_qps_prefix_f);
+    }
+  }
+
+  if (FLAGS_output_time_series) {
+    s = CreateOutputFile(type, new_stats.cf_name, "time_series.txt",
+                         &new_stats.time_series_f);
+  }
+
+  if (FLAGS_output_value_distribution) {
+    s = CreateOutputFile(type, new_stats.cf_name,
+                         "accessed_value_size_distribution.txt",
+                         &new_stats.a_value_size_f);
+  }
+
+  if (FLAGS_output_key_distribution) {
+    s = CreateOutputFile(type, new_stats.cf_name,
+                         "accessed_key_size_distribution.txt",
+                         &new_stats.a_key_size_f);
+  }
+
+  if (FLAGS_output_qps_stats) {
+    s = CreateOutputFile(type, new_stats.cf_name, "qps_stats.txt",
+                         &new_stats.a_qps_f);
+  }
+
+  return Status::OK();
+}
+
+// create the output path of the files to be opened
+Status TraceAnalyzer::CreateOutputFile(
+    const std::string& type, const std::string& cf_name,
+    const std::string& ending, std::unique_ptr<rocksdb::WritableFile>* f_ptr) {
+  std::string path;
+  path = output_path_ + "/" + FLAGS_output_prefix + "-" + type + "-" + cf_name +
+         "-" + ending;
+  Status s;
+  s = env_->NewWritableFile(path, f_ptr, env_options_);
+  if (!s.ok()) {
+    fprintf(stderr, "Cannot open file: %s\n", path.c_str());
+    exit(1);
+  }
+  return Status::OK();
+}
+
+// Close the output files in the TraceStats if they are opened
+void TraceAnalyzer::CloseOutputFiles() {
+  for (int type = 0; type < kTaTypeNum; type++) {
+    if (!ta_[type].enabled) {
+      continue;
+    }
+    for (auto& stat : ta_[type].stats) {
+      if (stat.second.time_series_f) {
+        stat.second.time_series_f->Close();
+      }
+
+      if (stat.second.a_key_f) {
+        stat.second.a_key_f->Close();
+      }
+
+      if (stat.second.a_key_num_f) {
+        stat.second.a_key_num_f->Close();
+      }
+
+      if (stat.second.a_count_dist_f) {
+        stat.second.a_count_dist_f->Close();
+      }
+
+      if (stat.second.a_prefix_cut_f) {
+        stat.second.a_prefix_cut_f->Close();
+      }
+
+      if (stat.second.a_value_size_f) {
+        stat.second.a_value_size_f->Close();
+      }
+
+      if (stat.second.a_key_size_f) {
+        stat.second.a_key_size_f->Close();
+      }
+
+      if (stat.second.a_qps_f) {
+        stat.second.a_qps_f->Close();
+      }
+
+      if (stat.second.a_top_qps_prefix_f) {
+        stat.second.a_top_qps_prefix_f->Close();
+      }
+
+      if (stat.second.w_key_f) {
+        stat.second.w_key_f->Close();
+      }
+      if (stat.second.w_prefix_cut_f) {
+        stat.second.w_prefix_cut_f->Close();
+      }
+    }
+  }
+  return;
+}
+
+// Handle the Get request in the trace
+Status TraceAnalyzer::HandleGet(uint32_t column_family_id,
+                                const std::string& key, const uint64_t& ts,
+                                const uint32_t& get_ret) {
+  Status s;
+  size_t value_size = 0;
+  if (FLAGS_convert_to_human_readable_trace && trace_sequence_f_) {
+    s = WriteTraceSequence(TraceOperationType::kGet, column_family_id, key,
+                           value_size, ts);
+    if (!s.ok()) {
+      return Status::Corruption("Failed to write the trace sequence to file");
+    }
+  }
+
+  if (ta_[TraceOperationType::kGet].sample_count >= sample_max_) {
+    ta_[TraceOperationType::kGet].sample_count = 0;
+  }
+  if (ta_[TraceOperationType::kGet].sample_count > 0) {
+    ta_[TraceOperationType::kGet].sample_count++;
+    return Status::OK();
+  }
+  ta_[TraceOperationType::kGet].sample_count++;
+
+  if (!ta_[TraceOperationType::kGet].enabled) {
+    return Status::OK();
+  }
+  if (get_ret == 1) {
+    value_size = 10;
+  }
+  s = KeyStatsInsertion(TraceOperationType::kGet, column_family_id, key,
+                        value_size, ts);
+  if (!s.ok()) {
+    return Status::Corruption("Failed to insert key statistics");
+  }
+  return s;
+}
+
+// Handle the Put request in the write batch of the trace
+Status TraceAnalyzer::HandlePut(uint32_t column_family_id, const Slice& key,
+                                const Slice& value) {
+  Status s;
+  size_t value_size = value.ToString().size();
+  if (FLAGS_convert_to_human_readable_trace && trace_sequence_f_) {
+    s = WriteTraceSequence(TraceOperationType::kPut, column_family_id,
+                           key.ToString(), value_size, c_time_);
+    if (!s.ok()) {
+      return Status::Corruption("Failed to write the trace sequence to file");
+    }
+  }
+
+  if (ta_[TraceOperationType::kPut].sample_count >= sample_max_) {
+    ta_[TraceOperationType::kPut].sample_count = 0;
+  }
+  if (ta_[TraceOperationType::kPut].sample_count > 0) {
+    ta_[TraceOperationType::kPut].sample_count++;
+    return Status::OK();
+  }
+  ta_[TraceOperationType::kPut].sample_count++;
+
+  if (!ta_[TraceOperationType::kPut].enabled) {
+    return Status::OK();
+  }
+  s = KeyStatsInsertion(TraceOperationType::kPut, column_family_id,
+                        key.ToString(), value_size, c_time_);
+  if (!s.ok()) {
+    return Status::Corruption("Failed to insert key statistics");
+  }
+  return s;
+}
+
+// Handle the Delete request in the write batch of the trace
+Status TraceAnalyzer::HandleDelete(uint32_t column_family_id,
+                                   const Slice& key) {
+  Status s;
+  size_t value_size = 0;
+  if (FLAGS_convert_to_human_readable_trace && trace_sequence_f_) {
+    s = WriteTraceSequence(TraceOperationType::kDelete, column_family_id,
+                           key.ToString(), value_size, c_time_);
+    if (!s.ok()) {
+      return Status::Corruption("Failed to write the trace sequence to file");
+    }
+  }
+
+  if (ta_[TraceOperationType::kDelete].sample_count >= sample_max_) {
+    ta_[TraceOperationType::kDelete].sample_count = 0;
+  }
+  if (ta_[TraceOperationType::kDelete].sample_count > 0) {
+    ta_[TraceOperationType::kDelete].sample_count++;
+    return Status::OK();
+  }
+  ta_[TraceOperationType::kDelete].sample_count++;
+
+  if (!ta_[TraceOperationType::kDelete].enabled) {
+    return Status::OK();
+  }
+  s = KeyStatsInsertion(TraceOperationType::kDelete, column_family_id,
+                        key.ToString(), value_size, c_time_);
+  if (!s.ok()) {
+    return Status::Corruption("Failed to insert key statistics");
+  }
+  return s;
+}
+
+// Handle the SingleDelete request in the write batch of the trace
+Status TraceAnalyzer::HandleSingleDelete(uint32_t column_family_id,
+                                         const Slice& key) {
+  Status s;
+  size_t value_size = 0;
+  if (FLAGS_convert_to_human_readable_trace && trace_sequence_f_) {
+    s = WriteTraceSequence(TraceOperationType::kSingleDelete, column_family_id,
+                           key.ToString(), value_size, c_time_);
+    if (!s.ok()) {
+      return Status::Corruption("Failed to write the trace sequence to file");
+    }
+  }
+
+  if (ta_[TraceOperationType::kSingleDelete].sample_count >= sample_max_) {
+    ta_[TraceOperationType::kSingleDelete].sample_count = 0;
+  }
+  if (ta_[TraceOperationType::kSingleDelete].sample_count > 0) {
+    ta_[TraceOperationType::kSingleDelete].sample_count++;
+    return Status::OK();
+  }
+  ta_[TraceOperationType::kSingleDelete].sample_count++;
+
+  if (!ta_[TraceOperationType::kSingleDelete].enabled) {
+    return Status::OK();
+  }
+  s = KeyStatsInsertion(TraceOperationType::kSingleDelete, column_family_id,
+                        key.ToString(), value_size, c_time_);
+  if (!s.ok()) {
+    return Status::Corruption("Failed to insert key statistics");
+  }
+  return s;
+}
+
+// Handle the DeleteRange request in the write batch of the trace
+Status TraceAnalyzer::HandleDeleteRange(uint32_t column_family_id,
+                                        const Slice& begin_key,
+                                        const Slice& end_key) {
+  Status s;
+  size_t value_size = 0;
+  if (FLAGS_convert_to_human_readable_trace && trace_sequence_f_) {
+    s = WriteTraceSequence(TraceOperationType::kRangeDelete, column_family_id,
+                           begin_key.ToString(), value_size, c_time_);
+    if (!s.ok()) {
+      return Status::Corruption("Failed to write the trace sequence to file");
+    }
+  }
+
+  if (ta_[TraceOperationType::kRangeDelete].sample_count >= sample_max_) {
+    ta_[TraceOperationType::kRangeDelete].sample_count = 0;
+  }
+  if (ta_[TraceOperationType::kRangeDelete].sample_count > 0) {
+    ta_[TraceOperationType::kRangeDelete].sample_count++;
+    return Status::OK();
+  }
+  ta_[TraceOperationType::kRangeDelete].sample_count++;
+
+  if (!ta_[TraceOperationType::kRangeDelete].enabled) {
+    return Status::OK();
+  }
+  s = KeyStatsInsertion(TraceOperationType::kRangeDelete, column_family_id,
+                        begin_key.ToString(), value_size, c_time_);
+  s = KeyStatsInsertion(TraceOperationType::kRangeDelete, column_family_id,
+                        end_key.ToString(), value_size, c_time_);
+  if (!s.ok()) {
+    return Status::Corruption("Failed to insert key statistics");
+  }
+  return s;
+}
+
+// Handle the Merge request in the write batch of the trace
+Status TraceAnalyzer::HandleMerge(uint32_t column_family_id, const Slice& key,
+                                  const Slice& value) {
+  Status s;
+  size_t value_size = value.ToString().size();
+  if (FLAGS_convert_to_human_readable_trace && trace_sequence_f_) {
+    s = WriteTraceSequence(TraceOperationType::kMerge, column_family_id,
+                           key.ToString(), value_size, c_time_);
+    if (!s.ok()) {
+      return Status::Corruption("Failed to write the trace sequence to file");
+    }
+  }
+
+  if (ta_[TraceOperationType::kMerge].sample_count >= sample_max_) {
+    ta_[TraceOperationType::kMerge].sample_count = 0;
+  }
+  if (ta_[TraceOperationType::kMerge].sample_count > 0) {
+    ta_[TraceOperationType::kMerge].sample_count++;
+    return Status::OK();
+  }
+  ta_[TraceOperationType::kMerge].sample_count++;
+
+  if (!ta_[TraceOperationType::kMerge].enabled) {
+    return Status::OK();
+  }
+  s = KeyStatsInsertion(TraceOperationType::kMerge, column_family_id,
+                        key.ToString(), value_size, c_time_);
+  if (!s.ok()) {
+    return Status::Corruption("Failed to insert key statistics");
+  }
+  return s;
+}
+
+// Handle the Iterator request in the trace
+Status TraceAnalyzer::HandleIter(uint32_t column_family_id,
+                                 const std::string& key, const uint64_t& ts,
+                                 TraceType& trace_type) {
+  Status s;
+  size_t value_size = 0;
+  int type = -1;
+  if (trace_type == kTraceIteratorSeek) {
+    type = TraceOperationType::kIteratorSeek;
+  } else if (trace_type == kTraceIteratorSeekForPrev) {
+    type = TraceOperationType::kIteratorSeekForPrev;
+  } else {
+    return s;
+  }
+  if (type == -1) {
+    return s;
+  }
+
+  if (FLAGS_convert_to_human_readable_trace && trace_sequence_f_) {
+    s = WriteTraceSequence(type, column_family_id, key, value_size, ts);
+    if (!s.ok()) {
+      return Status::Corruption("Failed to write the trace sequence to file");
+    }
+  }
+
+  if (ta_[type].sample_count >= sample_max_) {
+    ta_[type].sample_count = 0;
+  }
+  if (ta_[type].sample_count > 0) {
+    ta_[type].sample_count++;
+    return Status::OK();
+  }
+  ta_[type].sample_count++;
+
+  if (!ta_[type].enabled) {
+    return Status::OK();
+  }
+  s = KeyStatsInsertion(type, column_family_id, key, value_size, ts);
+  if (!s.ok()) {
+    return Status::Corruption("Failed to insert key statistics");
+  }
+  return s;
+}
+
+// Before the analyzer is closed, the requested general statistic results are
+// printed out here. In current stage, these information are not output to
+// the files.
+// -----type
+//          |__cf_id
+//                |_statistics
+void TraceAnalyzer::PrintStatistics() {
+  for (int type = 0; type < kTaTypeNum; type++) {
+    if (!ta_[type].enabled) {
+      continue;
+    }
+    ta_[type].total_keys = 0;
+    ta_[type].total_access = 0;
+    ta_[type].total_succ_access = 0;
+    printf("\n################# Operation Type: %s #####################\n",
+           ta_[type].type_name.c_str());
+    if (qps_ave_.size() == kTaTypeNum + 1) {
+      printf("Peak QPS is: %u Average QPS is: %f\n", qps_peak_[type],
+             qps_ave_[type]);
+    }
+    for (auto& stat_it : ta_[type].stats) {
+      if (stat_it.second.a_count == 0) {
+        continue;
+      }
+      TraceStats& stat = stat_it.second;
+      uint64_t total_a_keys = static_cast<uint64_t>(stat.a_key_stats.size());
+      double key_size_ave = 0.0;
+      double value_size_ave = 0.0;
+      double key_size_vari = 0.0;
+      double value_size_vari = 0.0;
+      if (stat.a_count > 0) {
+        key_size_ave =
+            (static_cast<double>(stat.a_key_size_sum)) / stat.a_count;
+        value_size_ave =
+            (static_cast<double>(stat.a_value_size_sum)) / stat.a_count;
+        key_size_vari = std::sqrt((static_cast<double>(stat.a_key_size_sqsum)) /
+                                      stat.a_count -
+                                  key_size_ave * key_size_ave);
+        value_size_vari = std::sqrt(
+            (static_cast<double>(stat.a_value_size_sqsum)) / stat.a_count -
+            value_size_ave * value_size_ave);
+      }
+      if (value_size_ave == 0.0) {
+        stat.a_value_mid = 0;
+      }
+      cfs_[stat.cf_id].a_count += total_a_keys;
+      ta_[type].total_keys += total_a_keys;
+      ta_[type].total_access += stat.a_count;
+      ta_[type].total_succ_access += stat.a_succ_count;
+      printf("*********************************************************\n");
+      printf("colume family id: %u\n", stat.cf_id);
+      printf("Total number of queries to this cf by %s: %" PRIu64 "\n",
+             ta_[type].type_name.c_str(), stat.a_count);
+      printf("Total unique keys in this cf: %" PRIu64 "\n", total_a_keys);
+      printf("Average key size: %f key size medium: %" PRIu64
+             " Key size Variation: %f\n",
+             key_size_ave, stat.a_key_mid, key_size_vari);
+      if (type == kPut || type == kMerge) {
+        printf("Average value size: %f Value size medium: %" PRIu64
+               " Value size variation: %f\n",
+               value_size_ave, stat.a_value_mid, value_size_vari);
+      }
+      printf("Peak QPS is: %u Average QPS is: %f\n", stat.a_peak_qps,
+             stat.a_ave_qps);
+
+      // print the top k accessed key and its access count
+      if (FLAGS_print_top_k_access > 0) {
+        printf("The Top %d keys that are accessed:\n",
+               FLAGS_print_top_k_access);
+        while (!stat.top_k_queue.empty()) {
+          std::string hex_key =
+              rocksdb::LDBCommand::StringToHex(stat.top_k_queue.top().second);
+          printf("Access_count: %" PRIu64 " %s\n", stat.top_k_queue.top().first,
+                 hex_key.c_str());
+          stat.top_k_queue.pop();
+        }
+      }
+
+      // print the top k access prefix range and
+      // top k prefix range with highest average access per key
+      if (FLAGS_output_prefix_cut > 0) {
+        printf("The Top %d accessed prefix range:\n", FLAGS_print_top_k_access);
+        while (!stat.top_k_prefix_access.empty()) {
+          printf("Prefix: %s Access count: %" PRIu64 "\n",
+                 stat.top_k_prefix_access.top().second.c_str(),
+                 stat.top_k_prefix_access.top().first);
+          stat.top_k_prefix_access.pop();
+        }
+
+        printf("The Top %d prefix with highest access per key:\n",
+               FLAGS_print_top_k_access);
+        while (!stat.top_k_prefix_ave.empty()) {
+          printf("Prefix: %s access per key: %f\n",
+                 stat.top_k_prefix_ave.top().second.c_str(),
+                 stat.top_k_prefix_ave.top().first);
+          stat.top_k_prefix_ave.pop();
+        }
+      }
+
+      // print the operation correlations
+      if (!FLAGS_print_correlation.empty()) {
+        for (int correlation = 0;
+             correlation <
+             static_cast<int>(analyzer_opts_.correlation_list.size());
+             correlation++) {
+          printf(
+              "The correlation statistics of '%s' after '%s' is:",
+              taIndexToOpt[analyzer_opts_.correlation_list[correlation].second]
+                  .c_str(),
+              taIndexToOpt[analyzer_opts_.correlation_list[correlation].first]
+                  .c_str());
+          double correlation_ave = 0.0;
+          if (stat.correlation_output[correlation].first > 0) {
+            correlation_ave =
+                (static_cast<double>(
+                    stat.correlation_output[correlation].second)) /
+                (stat.correlation_output[correlation].first * 1000);
+          }
+          printf(" total numbers: %" PRIu64 " average time: %f(ms)\n",
+                 stat.correlation_output[correlation].first, correlation_ave);
+        }
+      }
+    }
+    printf("*********************************************************\n");
+    printf("Total keys of '%s' is: %" PRIu64 "\n", ta_[type].type_name.c_str(),
+           ta_[type].total_keys);
+    printf("Total access is: %" PRIu64 "\n", ta_[type].total_access);
+    total_access_keys_ += ta_[type].total_keys;
+  }
+
+  // Print the overall statistic information of the trace
+  printf("\n*********************************************************\n");
+  printf("*********************************************************\n");
+  printf("The column family based statistics\n");
+  for (auto& cf : cfs_) {
+    printf("The column family id: %u\n", cf.first);
+    printf("The whole key space key numbers: %" PRIu64 "\n", cf.second.w_count);
+    printf("The accessed key space key numbers: %" PRIu64 "\n",
+           cf.second.a_count);
+  }
+
+  if (FLAGS_print_overall_stats) {
+    printf("\n*********************************************************\n");
+    printf("*********************************************************\n");
+    if (qps_peak_.size() == kTaTypeNum + 1) {
+      printf("Average QPS per second: %f Peak QPS: %u\n", qps_ave_[kTaTypeNum],
+             qps_peak_[kTaTypeNum]);
+    }
+    printf("The statistics related to query number need to times: %u\n",
+           sample_max_);
+    printf("Total_requests: %" PRIu64 " Total_accessed_keys: %" PRIu64
+           " Total_gets: %" PRIu64 " Total_write_batch: %" PRIu64 "\n",
+           total_requests_, total_access_keys_, total_gets_, total_writes_);
+    for (int type = 0; type < kTaTypeNum; type++) {
+      if (!ta_[type].enabled) {
+        continue;
+      }
+      printf("Operation: '%s' has: %" PRIu64 "\n", ta_[type].type_name.c_str(),
+             ta_[type].total_access);
+    }
+  }
+}
+
+// Write the trace sequence to file
+Status TraceAnalyzer::WriteTraceSequence(const uint32_t& type,
+                                         const uint32_t& cf_id,
+                                         const std::string& key,
+                                         const size_t value_size,
+                                         const uint64_t ts) {
+  std::string hex_key = rocksdb::LDBCommand::StringToHex(key);
+  int ret;
+  ret =
+      sprintf(buffer_, "%u %u %zu %" PRIu64 "\n", type, cf_id, value_size, ts);
+  if (ret < 0) {
+    return Status::IOError("failed to format the output");
+  }
+  std::string printout(buffer_);
+  if (!FLAGS_no_key) {
+    printout = hex_key + " " + printout;
+  }
+  return trace_sequence_f_->Append(printout);
+}
+
+// The entrance function of Trace_Analyzer
+int trace_analyzer_tool(int argc, char** argv) {
+  std::string trace_path;
+  std::string output_path;
+
+  AnalyzerOptions analyzer_opts;
+
+  ParseCommandLineFlags(&argc, &argv, true);
+
+  if (!FLAGS_print_correlation.empty()) {
+    analyzer_opts.SparseCorrelationInput(FLAGS_print_correlation);
+  }
+
+  std::unique_ptr<TraceAnalyzer> analyzer(
+      new TraceAnalyzer(FLAGS_trace_path, FLAGS_output_dir, analyzer_opts));
+
+  if (!analyzer) {
+    fprintf(stderr, "Cannot initiate the trace analyzer\n");
+    exit(1);
+  }
+
+  rocksdb::Status s = analyzer->PrepareProcessing();
+  if (!s.ok()) {
+    fprintf(stderr, "%s\n", s.getState());
+    fprintf(stderr, "Cannot initiate the trace reader\n");
+    exit(1);
+  }
+
+  s = analyzer->StartProcessing();
+  if (!s.ok() && !FLAGS_try_process_corrupted_trace) {
+    fprintf(stderr, "%s\n", s.getState());
+    fprintf(stderr, "Cannot processing the trace\n");
+    exit(1);
+  }
+
+  s = analyzer->MakeStatistics();
+  if (!s.ok()) {
+    fprintf(stderr, "%s\n", s.getState());
+    analyzer->EndProcessing();
+    fprintf(stderr, "Cannot make the statistics\n");
+    exit(1);
+  }
+
+  s = analyzer->ReProcessing();
+  if (!s.ok()) {
+    fprintf(stderr, "%s\n", s.getState());
+    fprintf(stderr, "Cannot re-process the trace for more statistics\n");
+    analyzer->EndProcessing();
+    exit(1);
+  }
+
+  s = analyzer->EndProcessing();
+  if (!s.ok()) {
+    fprintf(stderr, "%s\n", s.getState());
+    fprintf(stderr, "Cannot close the trace analyzer\n");
+    exit(1);
+  }
+
+  return 0;
+}
+}  // namespace rocksdb
+
+#endif  // Endif of Gflag
+#endif  // RocksDB LITE
diff --git a/src/rocksdb/tools/trace_analyzer_tool.h b/src/rocksdb/tools/trace_analyzer_tool.h
new file mode 100644
index 00000000..be96f500
--- /dev/null
+++ b/src/rocksdb/tools/trace_analyzer_tool.h
@@ -0,0 +1,290 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#pragma once
+#ifndef ROCKSDB_LITE
+
+#include <list>
+#include <map>
+#include <queue>
+#include <set>
+#include <utility>
+#include <vector>
+
+#include "rocksdb/env.h"
+#include "rocksdb/trace_reader_writer.h"
+#include "rocksdb/write_batch.h"
+#include "util/trace_replay.h"
+
+namespace rocksdb {
+
+class DBImpl;
+class WriteBatch;
+
+enum TraceOperationType : int {
+  kGet = 0,
+  kPut = 1,
+  kDelete = 2,
+  kSingleDelete = 3,
+  kRangeDelete = 4,
+  kMerge = 5,
+  kIteratorSeek = 6,
+  kIteratorSeekForPrev = 7,
+  kTaTypeNum = 8
+};
+
+struct TraceUnit {
+  uint64_t ts;
+  uint32_t type;
+  uint32_t cf_id;
+  size_t value_size;
+  std::string key;
+};
+
+struct TypeCorrelation {
+  uint64_t count;
+  uint64_t total_ts;
+};
+
+struct StatsUnit {
+  uint64_t key_id;
+  uint64_t access_count;
+  uint64_t latest_ts;
+  uint64_t succ_count;  // current only used to count Get if key found
+  uint32_t cf_id;
+  size_t value_size;
+  std::vector<TypeCorrelation> v_correlation;
+};
+
+class AnalyzerOptions {
+ public:
+  std::vector<std::vector<int>> correlation_map;
+  std::vector<std::pair<int, int>> correlation_list;
+
+  AnalyzerOptions();
+
+  ~AnalyzerOptions();
+
+  void SparseCorrelationInput(const std::string& in_str);
+};
+
+// Note that, for the variable names  in the trace_analyzer,
+// Starting with 'a_' means the variable is used for 'accessed_keys'.
+// Starting with 'w_' means it is used for 'the whole key space'.
+// Ending with '_f' means a file write or reader pointer.
+// For example, 'a_count' means 'accessed_keys_count',
+// 'w_key_f' means 'whole_key_space_file'.
+
+struct TraceStats {
+  uint32_t cf_id;
+  std::string cf_name;
+  uint64_t a_count;
+  uint64_t a_succ_count;
+  uint64_t a_key_id;
+  uint64_t a_key_size_sqsum;
+  uint64_t a_key_size_sum;
+  uint64_t a_key_mid;
+  uint64_t a_value_size_sqsum;
+  uint64_t a_value_size_sum;
+  uint64_t a_value_mid;
+  uint32_t a_peak_qps;
+  double a_ave_qps;
+  std::map<std::string, StatsUnit> a_key_stats;
+  std::map<uint64_t, uint64_t> a_count_stats;
+  std::map<uint64_t, uint64_t> a_key_size_stats;
+  std::map<uint64_t, uint64_t> a_value_size_stats;
+  std::map<uint32_t, uint32_t> a_qps_stats;
+  std::map<uint32_t, std::map<std::string, uint32_t>> a_qps_prefix_stats;
+  std::priority_queue<std::pair<uint64_t, std::string>,
+                      std::vector<std::pair<uint64_t, std::string>>,
+                      std::greater<std::pair<uint64_t, std::string>>>
+      top_k_queue;
+  std::priority_queue<std::pair<uint64_t, std::string>,
+                      std::vector<std::pair<uint64_t, std::string>>,
+                      std::greater<std::pair<uint64_t, std::string>>>
+      top_k_prefix_access;
+  std::priority_queue<std::pair<double, std::string>,
+                      std::vector<std::pair<double, std::string>>,
+                      std::greater<std::pair<double, std::string>>>
+      top_k_prefix_ave;
+  std::priority_queue<std::pair<uint32_t, uint32_t>,
+                      std::vector<std::pair<uint32_t, uint32_t>>,
+                      std::greater<std::pair<uint32_t, uint32_t>>>
+      top_k_qps_sec;
+  std::list<TraceUnit> time_series;
+  std::vector<std::pair<uint64_t, uint64_t>> correlation_output;
+  std::map<uint32_t, uint64_t> uni_key_num;
+
+  std::unique_ptr<rocksdb::WritableFile> time_series_f;
+  std::unique_ptr<rocksdb::WritableFile> a_key_f;
+  std::unique_ptr<rocksdb::WritableFile> a_count_dist_f;
+  std::unique_ptr<rocksdb::WritableFile> a_prefix_cut_f;
+  std::unique_ptr<rocksdb::WritableFile> a_value_size_f;
+  std::unique_ptr<rocksdb::WritableFile> a_key_size_f;
+  std::unique_ptr<rocksdb::WritableFile> a_key_num_f;
+  std::unique_ptr<rocksdb::WritableFile> a_qps_f;
+  std::unique_ptr<rocksdb::WritableFile> a_top_qps_prefix_f;
+  std::unique_ptr<rocksdb::WritableFile> w_key_f;
+  std::unique_ptr<rocksdb::WritableFile> w_prefix_cut_f;
+
+  TraceStats();
+  ~TraceStats();
+  TraceStats(const TraceStats&) = delete;
+  TraceStats& operator=(const TraceStats&) = delete;
+  TraceStats(TraceStats&&) = default;
+  TraceStats& operator=(TraceStats&&) = default;
+};
+
+struct TypeUnit {
+  std::string type_name;
+  bool enabled;
+  uint64_t total_keys;
+  uint64_t total_access;
+  uint64_t total_succ_access;
+  uint32_t sample_count;
+  std::map<uint32_t, TraceStats> stats;
+  TypeUnit() = default;
+  ~TypeUnit() = default;
+  TypeUnit(const TypeUnit&) = delete;
+  TypeUnit& operator=(const TypeUnit&) = delete;
+  TypeUnit(TypeUnit&&) = default;
+  TypeUnit& operator=(TypeUnit&&) = default;
+};
+
+struct CfUnit {
+  uint32_t cf_id;
+  uint64_t w_count;  // total keys in this cf if we use the whole key space
+  uint64_t a_count;  // the total keys in this cf that are accessed
+  std::map<uint64_t, uint64_t> w_key_size_stats;  // whole key space key size
+                                                  // statistic this cf
+  std::map<uint32_t, uint32_t> cf_qps;
+};
+
+class TraceAnalyzer {
+ public:
+  TraceAnalyzer(std::string& trace_path, std::string& output_path,
+                AnalyzerOptions _analyzer_opts);
+  ~TraceAnalyzer();
+
+  Status PrepareProcessing();
+
+  Status StartProcessing();
+
+  Status MakeStatistics();
+
+  Status ReProcessing();
+
+  Status EndProcessing();
+
+  Status WriteTraceUnit(TraceUnit& unit);
+
+  // The trace  processing functions for different type
+  Status HandleGet(uint32_t column_family_id, const std::string& key,
+                   const uint64_t& ts, const uint32_t& get_ret);
+  Status HandlePut(uint32_t column_family_id, const Slice& key,
+                   const Slice& value);
+  Status HandleDelete(uint32_t column_family_id, const Slice& key);
+  Status HandleSingleDelete(uint32_t column_family_id, const Slice& key);
+  Status HandleDeleteRange(uint32_t column_family_id, const Slice& begin_key,
+                           const Slice& end_key);
+  Status HandleMerge(uint32_t column_family_id, const Slice& key,
+                     const Slice& value);
+  Status HandleIter(uint32_t column_family_id, const std::string& key,
+                    const uint64_t& ts, TraceType& trace_type);
+  std::vector<TypeUnit>& GetTaVector() { return ta_; }
+
+ private:
+  rocksdb::Env* env_;
+  EnvOptions env_options_;
+  std::unique_ptr<TraceReader> trace_reader_;
+  size_t offset_;
+  char buffer_[1024];
+  uint64_t c_time_;
+  std::string trace_name_;
+  std::string output_path_;
+  AnalyzerOptions analyzer_opts_;
+  uint64_t total_requests_;
+  uint64_t total_access_keys_;
+  uint64_t total_gets_;
+  uint64_t total_writes_;
+  uint64_t trace_create_time_;
+  uint64_t begin_time_;
+  uint64_t end_time_;
+  uint64_t time_series_start_;
+  uint32_t sample_max_;
+  uint32_t cur_time_sec_;
+  std::unique_ptr<rocksdb::WritableFile> trace_sequence_f_;  // readable trace
+  std::unique_ptr<rocksdb::WritableFile> qps_f_;             // overall qps
+  std::unique_ptr<rocksdb::WritableFile> cf_qps_f_;  // The qps of each CF>
+  std::unique_ptr<rocksdb::SequentialFile> wkey_input_f_;
+  std::vector<TypeUnit> ta_;  // The main statistic collecting data structure
+  std::map<uint32_t, CfUnit> cfs_;  // All the cf_id appears in this trace;
+  std::vector<uint32_t> qps_peak_;
+  std::vector<double> qps_ave_;
+
+  Status ReadTraceHeader(Trace* header);
+  Status ReadTraceFooter(Trace* footer);
+  Status ReadTraceRecord(Trace* trace);
+  Status KeyStatsInsertion(const uint32_t& type, const uint32_t& cf_id,
+                           const std::string& key, const size_t value_size,
+                           const uint64_t ts);
+  Status StatsUnitCorrelationUpdate(StatsUnit& unit, const uint32_t& type,
+                                    const uint64_t& ts, const std::string& key);
+  Status OpenStatsOutputFiles(const std::string& type, TraceStats& new_stats);
+  Status CreateOutputFile(const std::string& type, const std::string& cf_name,
+                          const std::string& ending,
+                          std::unique_ptr<rocksdb::WritableFile>* f_ptr);
+  void CloseOutputFiles();
+
+  void PrintStatistics();
+  Status TraceUnitWriter(std::unique_ptr<rocksdb::WritableFile>& f_ptr,
+                         TraceUnit& unit);
+  Status WriteTraceSequence(const uint32_t& type, const uint32_t& cf_id,
+                            const std::string& key, const size_t value_size,
+                            const uint64_t ts);
+  Status MakeStatisticKeyStatsOrPrefix(TraceStats& stats);
+  Status MakeStatisticCorrelation(TraceStats& stats, StatsUnit& unit);
+  Status MakeStatisticQPS();
+};
+
+// write bach handler to be used for WriteBache iterator
+// when processing the write trace
+class TraceWriteHandler : public WriteBatch::Handler {
+ public:
+  TraceWriteHandler() { ta_ptr = nullptr; }
+  explicit TraceWriteHandler(TraceAnalyzer* _ta_ptr) { ta_ptr = _ta_ptr; }
+  ~TraceWriteHandler() {}
+
+  virtual Status PutCF(uint32_t column_family_id, const Slice& key,
+                       const Slice& value) override {
+    return ta_ptr->HandlePut(column_family_id, key, value);
+  }
+  virtual Status DeleteCF(uint32_t column_family_id,
+                          const Slice& key) override {
+    return ta_ptr->HandleDelete(column_family_id, key);
+  }
+  virtual Status SingleDeleteCF(uint32_t column_family_id,
+                                const Slice& key) override {
+    return ta_ptr->HandleSingleDelete(column_family_id, key);
+  }
+  virtual Status DeleteRangeCF(uint32_t column_family_id,
+                               const Slice& begin_key,
+                               const Slice& end_key) override {
+    return ta_ptr->HandleDeleteRange(column_family_id, begin_key, end_key);
+  }
+  virtual Status MergeCF(uint32_t column_family_id, const Slice& key,
+                         const Slice& value) override {
+    return ta_ptr->HandleMerge(column_family_id, key, value);
+  }
+
+ private:
+  TraceAnalyzer* ta_ptr;
+};
+
+int trace_analyzer_tool(int argc, char** argv);
+
+}  // namespace rocksdb
+
+#endif  // ROCKSDB_LITE
diff --git a/src/rocksdb/tools/verify_random_db.sh b/src/rocksdb/tools/verify_random_db.sh
new file mode 100755
index 00000000..12923300
--- /dev/null
+++ b/src/rocksdb/tools/verify_random_db.sh
@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+#
+# A shell script to verify DB generated by generate_random_db.sh cannot opened and read correct data.
+# ./ldb needs to be avaible to be executed.
+#
+# Usage: <SCRIPT> <DB Path>
+
+scriptpath=`dirname $BASH_SOURCE`
+if [ "$#" -lt 2 ]; then
+  echo "usage: $BASH_SOURCE <db_directory> <compare_base_db_directory> [dump_file_name] [if_try_load_options] [if_ignore_unknown_options]"
+  exit 1
+fi
+
+db_dir=$1
+base_db_dir=$2
+dump_file_name=${3:-"dump_file.txt"}
+try_load_options=${4:-"1"}
+ignore_unknown_options=${5:-"0"}
+db_dump=$db_dir"/"$dump_file_name
+base_db_dump=$base_db_dir"/"$dump_file_name
+extra_param=
+
+if [ "$try_load_options" = "1" ]; then
+ extra_param=" --try_load_options "
+fi
+
+if [ "$ignore_unknown_options" = "1" ]; then
+ extra_param=" --ignore_unknown_options "
+fi
+
+set -e
+echo == Dumping data from $db_dir to $db_dump
+./ldb dump --db=$db_dir $extra_param > $db_dump
+
+echo == Dumping data from $base_db_dir to $base_db_dump
+./ldb dump --db=$base_db_dir $extra_param > $base_db_dump
+
+diff $db_dump $base_db_dir
diff --git a/src/rocksdb/tools/write_external_sst.sh b/src/rocksdb/tools/write_external_sst.sh
new file mode 100755
index 00000000..6efc3002
--- /dev/null
+++ b/src/rocksdb/tools/write_external_sst.sh
@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+#
+#
+#
+
+if [ "$#" -lt 3 ]; then
+  echo "usage: $BASH_SOURCE <input_data_path> <DB Path> <extern SST dir>"
+  exit 1
+fi
+
+input_data_dir=$1
+db_dir=$2
+extern_sst_dir=$3
+rm -rf $db_dir
+
+set -e
+
+n=0
+
+for f in `find $input_data_dir -name sorted_data*`
+do
+  echo == Writing external SST file $f to $extern_sst_dir/extern_sst${n}
+  ./ldb --db=$db_dir --create_if_missing write_extern_sst $extern_sst_dir/extern_sst${n} < $f
+  let "n = n + 1"
+done
diff --git a/src/rocksdb/tools/write_stress.cc b/src/rocksdb/tools/write_stress.cc
new file mode 100644
index 00000000..ddb1d0ae
--- /dev/null
+++ b/src/rocksdb/tools/write_stress.cc
@@ -0,0 +1,309 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+//
+// The goal of this tool is to be a simple stress test with focus on catching:
+// * bugs in compaction/flush processes, especially the ones that cause
+// assertion errors
+// * bugs in the code that deletes obsolete files
+//
+// There are two parts of the test:
+// * write_stress, a binary that writes to the database
+// * write_stress_runner.py, a script that invokes and kills write_stress
+//
+// Here are some interesting parts of write_stress:
+// * Runs with very high concurrency of compactions and flushes (32 threads
+// total) and tries to create a huge amount of small files
+// * The keys written to the database are not uniformly distributed -- there is
+// a 3-character prefix that mutates occasionally (in prefix mutator thread), in
+// such a way that the first character mutates slower than second, which mutates
+// slower than third character. That way, the compaction stress tests some
+// interesting compaction features like trivial moves and bottommost level
+// calculation
+// * There is a thread that creates an iterator, holds it for couple of seconds
+// and then iterates over all keys. This is supposed to test RocksDB's abilities
+// to keep the files alive when there are references to them.
+// * Some writes trigger WAL sync. This is stress testing our WAL sync code.
+// * At the end of the run, we make sure that we didn't leak any of the sst
+// files
+//
+// write_stress_runner.py changes the mode in which we run write_stress and also
+// kills and restarts it. There are some interesting characteristics:
+// * At the beginning we divide the full test runtime into smaller parts --
+// shorter runtimes (couple of seconds) and longer runtimes (100, 1000) seconds
+// * The first time we run write_stress, we destroy the old DB. Every next time
+// during the test, we use the same DB.
+// * We can run in kill mode or clean-restart mode. Kill mode kills the
+// write_stress violently.
+// * We can run in mode where delete_obsolete_files_with_fullscan is true or
+// false
+// * We can run with low_open_files mode turned on or off. When it's turned on,
+// we configure table cache to only hold a couple of files -- that way we need
+// to reopen files every time we access them.
+//
+// Another goal was to create a stress test without a lot of parameters. So
+// tools/write_stress_runner.py should only take one parameter -- runtime_sec
+// and it should figure out everything else on its own.
+
+#include <cstdio>
+
+#ifndef GFLAGS
+int main() {
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+  return 1;
+}
+#else
+
+#ifndef __STDC_FORMAT_MACROS
+#define __STDC_FORMAT_MACROS
+#endif // __STDC_FORMAT_MACROS
+
+#include <inttypes.h>
+#include <atomic>
+#include <random>
+#include <set>
+#include <string>
+#include <thread>
+
+#include "port/port.h"
+#include "rocksdb/db.h"
+#include "rocksdb/env.h"
+#include "rocksdb/options.h"
+#include "rocksdb/slice.h"
+#include "util/filename.h"
+#include "util/gflags_compat.h"
+
+using GFLAGS_NAMESPACE::ParseCommandLineFlags;
+using GFLAGS_NAMESPACE::RegisterFlagValidator;
+using GFLAGS_NAMESPACE::SetUsageMessage;
+
+DEFINE_int32(key_size, 10, "Key size");
+DEFINE_int32(value_size, 100, "Value size");
+DEFINE_string(db, "", "Use the db with the following name.");
+DEFINE_bool(destroy_db, true,
+            "Destroy the existing DB before running the test");
+
+DEFINE_int32(runtime_sec, 10 * 60, "How long are we running for, in seconds");
+DEFINE_int32(seed, 139, "Random seed");
+
+DEFINE_double(prefix_mutate_period_sec, 1.0,
+              "How often are we going to mutate the prefix");
+DEFINE_double(first_char_mutate_probability, 0.1,
+              "How likely are we to mutate the first char every period");
+DEFINE_double(second_char_mutate_probability, 0.2,
+              "How likely are we to mutate the second char every period");
+DEFINE_double(third_char_mutate_probability, 0.5,
+              "How likely are we to mutate the third char every period");
+
+DEFINE_int32(iterator_hold_sec, 5,
+             "How long will the iterator hold files before it gets destroyed");
+
+DEFINE_double(sync_probability, 0.01, "How often are we syncing writes");
+DEFINE_bool(delete_obsolete_files_with_fullscan, false,
+            "If true, we delete obsolete files after each compaction/flush "
+            "using GetChildren() API");
+DEFINE_bool(low_open_files_mode, false,
+            "If true, we set max_open_files to 20, so that every file access "
+            "needs to reopen it");
+
+namespace rocksdb {
+
+static const int kPrefixSize = 3;
+
+class WriteStress {
+ public:
+  WriteStress() : stop_(false) {
+    // initialize key_prefix
+    for (int i = 0; i < kPrefixSize; ++i) {
+      key_prefix_[i].store('a');
+    }
+
+    // Choose a location for the test database if none given with --db=<path>
+    if (FLAGS_db.empty()) {
+      std::string default_db_path;
+      Env::Default()->GetTestDirectory(&default_db_path);
+      default_db_path += "/write_stress";
+      FLAGS_db = default_db_path;
+    }
+
+    Options options;
+    if (FLAGS_destroy_db) {
+      DestroyDB(FLAGS_db, options);  // ignore
+    }
+
+    // make the LSM tree deep, so that we have many concurrent flushes and
+    // compactions
+    options.create_if_missing = true;
+    options.write_buffer_size = 256 * 1024;              // 256k
+    options.max_bytes_for_level_base = 1 * 1024 * 1024;  // 1MB
+    options.target_file_size_base = 100 * 1024;          // 100k
+    options.max_write_buffer_number = 16;
+    options.max_background_compactions = 16;
+    options.max_background_flushes = 16;
+    options.max_open_files = FLAGS_low_open_files_mode ? 20 : -1;
+    if (FLAGS_delete_obsolete_files_with_fullscan) {
+      options.delete_obsolete_files_period_micros = 0;
+    }
+
+    // open DB
+    DB* db;
+    Status s = DB::Open(options, FLAGS_db, &db);
+    if (!s.ok()) {
+      fprintf(stderr, "Can't open database: %s\n", s.ToString().c_str());
+      std::abort();
+    }
+    db_.reset(db);
+  }
+
+  void WriteThread() {
+    std::mt19937 rng(static_cast<unsigned int>(FLAGS_seed));
+    std::uniform_real_distribution<double> dist(0, 1);
+
+    auto random_string = [](std::mt19937& r, int len) {
+      std::uniform_int_distribution<int> char_dist('a', 'z');
+      std::string ret;
+      for (int i = 0; i < len; ++i) {
+        ret += static_cast<char>(char_dist(r));
+      }
+      return ret;
+    };
+
+    while (!stop_.load(std::memory_order_relaxed)) {
+      std::string prefix;
+      prefix.resize(kPrefixSize);
+      for (int i = 0; i < kPrefixSize; ++i) {
+        prefix[i] = key_prefix_[i].load(std::memory_order_relaxed);
+      }
+      auto key = prefix + random_string(rng, FLAGS_key_size - kPrefixSize);
+      auto value = random_string(rng, FLAGS_value_size);
+      WriteOptions woptions;
+      woptions.sync = dist(rng) < FLAGS_sync_probability;
+      auto s = db_->Put(woptions, key, value);
+      if (!s.ok()) {
+        fprintf(stderr, "Write to DB failed: %s\n", s.ToString().c_str());
+        std::abort();
+      }
+    }
+  }
+
+  void IteratorHoldThread() {
+    while (!stop_.load(std::memory_order_relaxed)) {
+      std::unique_ptr<Iterator> iterator(db_->NewIterator(ReadOptions()));
+      Env::Default()->SleepForMicroseconds(FLAGS_iterator_hold_sec * 1000 *
+                                           1000LL);
+      for (iterator->SeekToFirst(); iterator->Valid(); iterator->Next()) {
+      }
+      if (!iterator->status().ok()) {
+        fprintf(stderr, "Iterator statuts not OK: %s\n",
+                iterator->status().ToString().c_str());
+        std::abort();
+      }
+    }
+  }
+
+  void PrefixMutatorThread() {
+    std::mt19937 rng(static_cast<unsigned int>(FLAGS_seed));
+    std::uniform_real_distribution<double> dist(0, 1);
+    std::uniform_int_distribution<int> char_dist('a', 'z');
+    while (!stop_.load(std::memory_order_relaxed)) {
+      Env::Default()->SleepForMicroseconds(static_cast<int>(
+                                           FLAGS_prefix_mutate_period_sec *
+                                           1000 * 1000LL));
+      if (dist(rng) < FLAGS_first_char_mutate_probability) {
+        key_prefix_[0].store(static_cast<char>(char_dist(rng)), std::memory_order_relaxed);
+      }
+      if (dist(rng) < FLAGS_second_char_mutate_probability) {
+        key_prefix_[1].store(static_cast<char>(char_dist(rng)), std::memory_order_relaxed);
+      }
+      if (dist(rng) < FLAGS_third_char_mutate_probability) {
+        key_prefix_[2].store(static_cast<char>(char_dist(rng)), std::memory_order_relaxed);
+      }
+    }
+  }
+
+  int Run() {
+    threads_.emplace_back([&]() { WriteThread(); });
+    threads_.emplace_back([&]() { PrefixMutatorThread(); });
+    threads_.emplace_back([&]() { IteratorHoldThread(); });
+
+    if (FLAGS_runtime_sec == -1) {
+      // infinite runtime, until we get killed
+      while (true) {
+        Env::Default()->SleepForMicroseconds(1000 * 1000);
+      }
+    }
+
+    Env::Default()->SleepForMicroseconds(FLAGS_runtime_sec * 1000 * 1000);
+
+    stop_.store(true, std::memory_order_relaxed);
+    for (auto& t : threads_) {
+      t.join();
+    }
+    threads_.clear();
+
+// Skip checking for leaked files in ROCKSDB_LITE since we don't have access to
+// function GetLiveFilesMetaData
+#ifndef ROCKSDB_LITE
+    // let's see if we leaked some files
+    db_->PauseBackgroundWork();
+    std::vector<LiveFileMetaData> metadata;
+    db_->GetLiveFilesMetaData(&metadata);
+    std::set<uint64_t> sst_file_numbers;
+    for (const auto& file : metadata) {
+      uint64_t number;
+      FileType type;
+      if (!ParseFileName(file.name, &number, "LOG", &type)) {
+        continue;
+      }
+      if (type == kTableFile) {
+        sst_file_numbers.insert(number);
+      }
+    }
+
+    std::vector<std::string> children;
+    Env::Default()->GetChildren(FLAGS_db, &children);
+    for (const auto& child : children) {
+      uint64_t number;
+      FileType type;
+      if (!ParseFileName(child, &number, "LOG", &type)) {
+        continue;
+      }
+      if (type == kTableFile) {
+        if (sst_file_numbers.find(number) == sst_file_numbers.end()) {
+          fprintf(stderr,
+                  "Found a table file in DB path that should have been "
+                  "deleted: %s\n",
+                  child.c_str());
+          std::abort();
+        }
+      }
+    }
+    db_->ContinueBackgroundWork();
+#endif  // !ROCKSDB_LITE
+
+    return 0;
+  }
+
+ private:
+  // each key is prepended with this prefix. we occasionally change it. third
+  // letter is changed more frequently than second, which is changed more
+  // frequently than the first one.
+  std::atomic<char> key_prefix_[kPrefixSize];
+  std::atomic<bool> stop_;
+  std::vector<port::Thread> threads_;
+  std::unique_ptr<DB> db_;
+};
+
+}  // namespace rocksdb
+
+int main(int argc, char** argv) {
+  SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) +
+                  " [OPTIONS]...");
+  ParseCommandLineFlags(&argc, &argv, true);
+  rocksdb::WriteStress write_stress;
+  return write_stress.Run();
+}
+
+#endif  // GFLAGS
diff --git a/src/rocksdb/tools/write_stress_runner.py b/src/rocksdb/tools/write_stress_runner.py
new file mode 100644
index 00000000..b84dfd3c
--- /dev/null
+++ b/src/rocksdb/tools/write_stress_runner.py
@@ -0,0 +1,73 @@
+#! /usr/bin/env python
+import subprocess
+import argparse
+import random
+import time
+import sys
+
+
+def generate_runtimes(total_runtime):
+    # combination of short runtimes and long runtimes, with heavier
+    # weight on short runtimes
+    possible_runtimes_sec = range(1, 10) + range(1, 20) + [100, 1000]
+    runtimes = []
+    while total_runtime > 0:
+        chosen = random.choice(possible_runtimes_sec)
+        chosen = min(chosen, total_runtime)
+        runtimes.append(chosen)
+        total_runtime -= chosen
+    return runtimes
+
+
+def main(args):
+    runtimes = generate_runtimes(int(args.runtime_sec))
+    print "Going to execute write stress for " + str(runtimes)  # noqa: E999 T25377293 Grandfathered in
+    first_time = True
+
+    for runtime in runtimes:
+        kill = random.choice([False, True])
+
+        cmd = './write_stress --runtime_sec=' + \
+            ("-1" if kill else str(runtime))
+
+        if len(args.db) > 0:
+            cmd = cmd + ' --db=' + args.db
+
+        if first_time:
+            first_time = False
+        else:
+            # use current db
+            cmd = cmd + ' --destroy_db=false'
+        if random.choice([False, True]):
+            cmd = cmd + ' --delete_obsolete_files_with_fullscan=true'
+        if random.choice([False, True]):
+            cmd = cmd + ' --low_open_files_mode=true'
+
+        print("Running write_stress for %d seconds (%s): %s" %
+              (runtime, ("kill-mode" if kill else "clean-shutdown-mode"),
+              cmd))
+
+        child = subprocess.Popen([cmd], shell=True)
+        killtime = time.time() + runtime
+        while not kill or time.time() < killtime:
+            time.sleep(1)
+            if child.poll() is not None:
+                if child.returncode == 0:
+                    break
+                else:
+                    print("ERROR: write_stress died with exitcode=%d\n"
+                          % child.returncode)
+                    sys.exit(1)
+        if kill:
+            child.kill()
+        # breathe
+        time.sleep(3)
+
+if __name__ == '__main__':
+    random.seed(time.time())
+    parser = argparse.ArgumentParser(description="This script runs and kills \
+        write_stress multiple times")
+    parser.add_argument("--runtime_sec", default='1000')
+    parser.add_argument("--db", default='')
+    args = parser.parse_args()
+    main(args)