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// 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.
#pragma once
#include <atomic>
#include <deque>
#include <limits>
#include <list>
#include <set>
#include <string>
#include <utility>
#include <vector>
#include "db/blob/blob_file_completion_callback.h"
#include "db/column_family.h"
#include "db/flush_scheduler.h"
#include "db/internal_stats.h"
#include "db/job_context.h"
#include "db/log_writer.h"
#include "db/logs_with_prep_tracker.h"
#include "db/memtable_list.h"
#include "db/seqno_to_time_mapping.h"
#include "db/snapshot_impl.h"
#include "db/version_edit.h"
#include "db/write_controller.h"
#include "db/write_thread.h"
#include "logging/event_logger.h"
#include "monitoring/instrumented_mutex.h"
#include "options/db_options.h"
#include "port/port.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/listener.h"
#include "rocksdb/memtablerep.h"
#include "rocksdb/transaction_log.h"
#include "table/scoped_arena_iterator.h"
#include "util/autovector.h"
#include "util/stop_watch.h"
#include "util/thread_local.h"
namespace ROCKSDB_NAMESPACE {
class DBImpl;
class MemTable;
class SnapshotChecker;
class TableCache;
class Version;
class VersionEdit;
class VersionSet;
class Arena;
class FlushJob {
public:
// TODO(icanadi) make effort to reduce number of parameters here
// IMPORTANT: mutable_cf_options needs to be alive while FlushJob is alive
FlushJob(const std::string& dbname, ColumnFamilyData* cfd,
const ImmutableDBOptions& db_options,
const MutableCFOptions& mutable_cf_options, uint64_t max_memtable_id,
const FileOptions& file_options, VersionSet* versions,
InstrumentedMutex* db_mutex, std::atomic<bool>* shutting_down,
std::vector<SequenceNumber> existing_snapshots,
SequenceNumber earliest_write_conflict_snapshot,
SnapshotChecker* snapshot_checker, JobContext* job_context,
LogBuffer* log_buffer, FSDirectory* db_directory,
FSDirectory* output_file_directory,
CompressionType output_compression, Statistics* stats,
EventLogger* event_logger, bool measure_io_stats,
const bool sync_output_directory, const bool write_manifest,
Env::Priority thread_pri, const std::shared_ptr<IOTracer>& io_tracer,
const SeqnoToTimeMapping& seq_time_mapping,
const std::string& db_id = "", const std::string& db_session_id = "",
std::string full_history_ts_low = "",
BlobFileCompletionCallback* blob_callback = nullptr);
~FlushJob();
// Require db_mutex held.
// Once PickMemTable() is called, either Run() or Cancel() has to be called.
void PickMemTable();
Status Run(LogsWithPrepTracker* prep_tracker = nullptr,
FileMetaData* file_meta = nullptr,
bool* switched_to_mempurge = nullptr);
void Cancel();
const autovector<MemTable*>& GetMemTables() const { return mems_; }
#ifndef ROCKSDB_LITE
std::list<std::unique_ptr<FlushJobInfo>>* GetCommittedFlushJobsInfo() {
return &committed_flush_jobs_info_;
}
#endif // !ROCKSDB_LITE
private:
friend class FlushJobTest_GetRateLimiterPriorityForWrite_Test;
void ReportStartedFlush();
void ReportFlushInputSize(const autovector<MemTable*>& mems);
void RecordFlushIOStats();
Status WriteLevel0Table();
// Memtable Garbage Collection algorithm: a MemPurge takes the list
// of immutable memtables and filters out (or "purge") the outdated bytes
// out of it. The output (the filtered bytes, or "useful payload") is
// then transfered into a new memtable. If this memtable is filled, then
// the mempurge is aborted and rerouted to a regular flush process. Else,
// depending on the heuristics, placed onto the immutable memtable list.
// The addition to the imm list will not trigger a flush operation. The
// flush of the imm list will instead be triggered once the mutable memtable
// is added to the imm list.
// This process is typically intended for workloads with heavy overwrites
// when we want to avoid SSD writes (and reads) as much as possible.
// "MemPurge" is an experimental feature still at a very early stage
// of development. At the moment it is only compatible with the Get, Put,
// Delete operations as well as Iterators and CompactionFilters.
// For this early version, "MemPurge" is called by setting the
// options.experimental_mempurge_threshold value as >0.0. When this is
// the case, ALL automatic flush operations (kWRiteBufferManagerFull) will
// first go through the MemPurge process. Therefore, we strongly
// recommend all users not to set this flag as true given that the MemPurge
// process has not matured yet.
Status MemPurge();
bool MemPurgeDecider(double threshold);
// The rate limiter priority (io_priority) is determined dynamically here.
Env::IOPriority GetRateLimiterPriorityForWrite();
#ifndef ROCKSDB_LITE
std::unique_ptr<FlushJobInfo> GetFlushJobInfo() const;
#endif // !ROCKSDB_LITE
const std::string& dbname_;
const std::string db_id_;
const std::string db_session_id_;
ColumnFamilyData* cfd_;
const ImmutableDBOptions& db_options_;
const MutableCFOptions& mutable_cf_options_;
// A variable storing the largest memtable id to flush in this
// flush job. RocksDB uses this variable to select the memtables to flush in
// this job. All memtables in this column family with an ID smaller than or
// equal to max_memtable_id_ will be selected for flush.
uint64_t max_memtable_id_;
const FileOptions file_options_;
VersionSet* versions_;
InstrumentedMutex* db_mutex_;
std::atomic<bool>* shutting_down_;
std::vector<SequenceNumber> existing_snapshots_;
SequenceNumber earliest_write_conflict_snapshot_;
SnapshotChecker* snapshot_checker_;
JobContext* job_context_;
LogBuffer* log_buffer_;
FSDirectory* db_directory_;
FSDirectory* output_file_directory_;
CompressionType output_compression_;
Statistics* stats_;
EventLogger* event_logger_;
TableProperties table_properties_;
bool measure_io_stats_;
// True if this flush job should call fsync on the output directory. False
// otherwise.
// Usually sync_output_directory_ is true. A flush job needs to call sync on
// the output directory before committing to the MANIFEST.
// However, an individual flush job does not have to call sync on the output
// directory if it is part of an atomic flush. After all flush jobs in the
// atomic flush succeed, call sync once on each distinct output directory.
const bool sync_output_directory_;
// True if this flush job should write to MANIFEST after successfully
// flushing memtables. False otherwise.
// Usually write_manifest_ is true. A flush job commits to the MANIFEST after
// flushing the memtables.
// However, an individual flush job cannot rashly write to the MANIFEST
// immediately after it finishes the flush if it is part of an atomic flush.
// In this case, only after all flush jobs succeed in flush can RocksDB
// commit to the MANIFEST.
const bool write_manifest_;
// The current flush job can commit flush result of a concurrent flush job.
// We collect FlushJobInfo of all jobs committed by current job and fire
// OnFlushCompleted for them.
std::list<std::unique_ptr<FlushJobInfo>> committed_flush_jobs_info_;
// Variables below are set by PickMemTable():
FileMetaData meta_;
autovector<MemTable*> mems_;
VersionEdit* edit_;
Version* base_;
bool pick_memtable_called;
Env::Priority thread_pri_;
const std::shared_ptr<IOTracer> io_tracer_;
SystemClock* clock_;
const std::string full_history_ts_low_;
BlobFileCompletionCallback* blob_callback_;
// reference to the seqno_time_mapping_ in db_impl.h, not safe to read without
// db mutex
const SeqnoToTimeMapping& db_impl_seqno_time_mapping_;
SeqnoToTimeMapping seqno_to_time_mapping_;
};
} // namespace ROCKSDB_NAMESPACE
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