1 files changed, 347 insertions, 0 deletions
diff --git a/src/rocksdb/table/block_based/block_based_filter_block.cc b/src/rocksdb/table/block_based/block_based_filter_block.cc
new file mode 100644
index 000000000..de3f5cb13
--- /dev/null
+++ b/src/rocksdb/table/block_based/block_based_filter_block.cc
@@ -0,0 +1,347 @@
+//  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.
+
+#include "table/block_based/block_based_filter_block.h"
+#include <algorithm>
+
+#include "db/dbformat.h"
+#include "monitoring/perf_context_imp.h"
+#include "rocksdb/filter_policy.h"
+#include "table/block_based/block_based_table_reader.h"
+#include "util/coding.h"
+#include "util/string_util.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+namespace {
+
+void AppendItem(std::string* props, const std::string& key,
+                const std::string& value) {
+  char cspace = ' ';
+  std::string value_str("");
+  size_t i = 0;
+  const size_t dataLength = 64;
+  const size_t tabLength = 2;
+  const size_t offLength = 16;
+
+  value_str.append(&value[i], std::min(size_t(dataLength), value.size()));
+  i += dataLength;
+  while (i < value.size()) {
+    value_str.append("\n");
+    value_str.append(offLength, cspace);
+    value_str.append(&value[i], std::min(size_t(dataLength), value.size() - i));
+    i += dataLength;
+  }
+
+  std::string result("");
+  if (key.size() < (offLength - tabLength))
+    result.append(size_t((offLength - tabLength)) - key.size(), cspace);
+  result.append(key);
+
+  props->append(result + ": " + value_str + "\n");
+}
+
+template <class TKey>
+void AppendItem(std::string* props, const TKey& key, const std::string& value) {
+  std::string key_str = ROCKSDB_NAMESPACE::ToString(key);
+  AppendItem(props, key_str, value);
+}
+}  // namespace
+
+// See doc/table_format.txt for an explanation of the filter block format.
+
+// Generate new filter every 2KB of data
+static const size_t kFilterBaseLg = 11;
+static const size_t kFilterBase = 1 << kFilterBaseLg;
+
+BlockBasedFilterBlockBuilder::BlockBasedFilterBlockBuilder(
+    const SliceTransform* prefix_extractor,
+    const BlockBasedTableOptions& table_opt)
+    : policy_(table_opt.filter_policy.get()),
+      prefix_extractor_(prefix_extractor),
+      whole_key_filtering_(table_opt.whole_key_filtering),
+      prev_prefix_start_(0),
+      prev_prefix_size_(0),
+      num_added_(0) {
+  assert(policy_);
+}
+
+void BlockBasedFilterBlockBuilder::StartBlock(uint64_t block_offset) {
+  uint64_t filter_index = (block_offset / kFilterBase);
+  assert(filter_index >= filter_offsets_.size());
+  while (filter_index > filter_offsets_.size()) {
+    GenerateFilter();
+  }
+}
+
+void BlockBasedFilterBlockBuilder::Add(const Slice& key) {
+  if (prefix_extractor_ && prefix_extractor_->InDomain(key)) {
+    AddPrefix(key);
+  }
+
+  if (whole_key_filtering_) {
+    AddKey(key);
+  }
+}
+
+// Add key to filter if needed
+inline void BlockBasedFilterBlockBuilder::AddKey(const Slice& key) {
+  num_added_++;
+  start_.push_back(entries_.size());
+  entries_.append(key.data(), key.size());
+}
+
+// Add prefix to filter if needed
+inline void BlockBasedFilterBlockBuilder::AddPrefix(const Slice& key) {
+  // get slice for most recently added entry
+  Slice prev;
+  if (prev_prefix_size_ > 0) {
+    prev = Slice(entries_.data() + prev_prefix_start_, prev_prefix_size_);
+  }
+
+  Slice prefix = prefix_extractor_->Transform(key);
+  // insert prefix only when it's different from the previous prefix.
+  if (prev.size() == 0 || prefix != prev) {
+    prev_prefix_start_ = entries_.size();
+    prev_prefix_size_ = prefix.size();
+    AddKey(prefix);
+  }
+}
+
+Slice BlockBasedFilterBlockBuilder::Finish(const BlockHandle& /*tmp*/,
+                                           Status* status) {
+  // In this impl we ignore BlockHandle
+  *status = Status::OK();
+  if (!start_.empty()) {
+    GenerateFilter();
+  }
+
+  // Append array of per-filter offsets
+  const uint32_t array_offset = static_cast<uint32_t>(result_.size());
+  for (size_t i = 0; i < filter_offsets_.size(); i++) {
+    PutFixed32(&result_, filter_offsets_[i]);
+  }
+
+  PutFixed32(&result_, array_offset);
+  result_.push_back(kFilterBaseLg);  // Save encoding parameter in result
+  return Slice(result_);
+}
+
+void BlockBasedFilterBlockBuilder::GenerateFilter() {
+  const size_t num_entries = start_.size();
+  if (num_entries == 0) {
+    // Fast path if there are no keys for this filter
+    filter_offsets_.push_back(static_cast<uint32_t>(result_.size()));
+    return;
+  }
+
+  // Make list of keys from flattened key structure
+  start_.push_back(entries_.size());  // Simplify length computation
+  tmp_entries_.resize(num_entries);
+  for (size_t i = 0; i < num_entries; i++) {
+    const char* base = entries_.data() + start_[i];
+    size_t length = start_[i + 1] - start_[i];
+    tmp_entries_[i] = Slice(base, length);
+  }
+
+  // Generate filter for current set of keys and append to result_.
+  filter_offsets_.push_back(static_cast<uint32_t>(result_.size()));
+  policy_->CreateFilter(&tmp_entries_[0], static_cast<int>(num_entries),
+                        &result_);
+
+  tmp_entries_.clear();
+  entries_.clear();
+  start_.clear();
+  prev_prefix_start_ = 0;
+  prev_prefix_size_ = 0;
+}
+
+BlockBasedFilterBlockReader::BlockBasedFilterBlockReader(
+    const BlockBasedTable* t, CachableEntry<BlockContents>&& filter_block)
+    : FilterBlockReaderCommon(t, std::move(filter_block)) {
+  assert(table());
+  assert(table()->get_rep());
+  assert(table()->get_rep()->filter_policy);
+}
+
+std::unique_ptr<FilterBlockReader> BlockBasedFilterBlockReader::Create(
+    const BlockBasedTable* table, FilePrefetchBuffer* prefetch_buffer,
+    bool use_cache, bool prefetch, bool pin,
+    BlockCacheLookupContext* lookup_context) {
+  assert(table);
+  assert(table->get_rep());
+  assert(!pin || prefetch);
+
+  CachableEntry<BlockContents> filter_block;
+  if (prefetch || !use_cache) {
+    const Status s = ReadFilterBlock(table, prefetch_buffer, ReadOptions(),
+                                     use_cache, nullptr /* get_context */,
+                                     lookup_context, &filter_block);
+    if (!s.ok()) {
+      return std::unique_ptr<FilterBlockReader>();
+    }
+
+    if (use_cache && !pin) {
+      filter_block.Reset();
+    }
+  }
+
+  return std::unique_ptr<FilterBlockReader>(
+      new BlockBasedFilterBlockReader(table, std::move(filter_block)));
+}
+
+bool BlockBasedFilterBlockReader::KeyMayMatch(
+    const Slice& key, const SliceTransform* /* prefix_extractor */,
+    uint64_t block_offset, const bool no_io,
+    const Slice* const /*const_ikey_ptr*/, GetContext* get_context,
+    BlockCacheLookupContext* lookup_context) {
+  assert(block_offset != kNotValid);
+  if (!whole_key_filtering()) {
+    return true;
+  }
+  return MayMatch(key, block_offset, no_io, get_context, lookup_context);
+}
+
+bool BlockBasedFilterBlockReader::PrefixMayMatch(
+    const Slice& prefix, const SliceTransform* /* prefix_extractor */,
+    uint64_t block_offset, const bool no_io,
+    const Slice* const /*const_ikey_ptr*/, GetContext* get_context,
+    BlockCacheLookupContext* lookup_context) {
+  assert(block_offset != kNotValid);
+  return MayMatch(prefix, block_offset, no_io, get_context, lookup_context);
+}
+
+bool BlockBasedFilterBlockReader::ParseFieldsFromBlock(
+    const BlockContents& contents, const char** data, const char** offset,
+    size_t* num, size_t* base_lg) {
+  assert(data);
+  assert(offset);
+  assert(num);
+  assert(base_lg);
+
+  const size_t n = contents.data.size();
+  if (n < 5) {  // 1 byte for base_lg and 4 for start of offset array
+    return false;
+  }
+
+  const uint32_t last_word = DecodeFixed32(contents.data.data() + n - 5);
+  if (last_word > n - 5) {
+    return false;
+  }
+
+  *data = contents.data.data();
+  *offset = (*data) + last_word;
+  *num = (n - 5 - last_word) / 4;
+  *base_lg = contents.data[n - 1];
+
+  return true;
+}
+
+bool BlockBasedFilterBlockReader::MayMatch(
+    const Slice& entry, uint64_t block_offset, bool no_io,
+    GetContext* get_context, BlockCacheLookupContext* lookup_context) const {
+  CachableEntry<BlockContents> filter_block;
+
+  const Status s =
+      GetOrReadFilterBlock(no_io, get_context, lookup_context, &filter_block);
+  if (!s.ok()) {
+    return true;
+  }
+
+  assert(filter_block.GetValue());
+
+  const char* data = nullptr;
+  const char* offset = nullptr;
+  size_t num = 0;
+  size_t base_lg = 0;
+  if (!ParseFieldsFromBlock(*filter_block.GetValue(), &data, &offset, &num,
+                            &base_lg)) {
+    return true;  // Errors are treated as potential matches
+  }
+
+  const uint64_t index = block_offset >> base_lg;
+  if (index < num) {
+    const uint32_t start = DecodeFixed32(offset + index * 4);
+    const uint32_t limit = DecodeFixed32(offset + index * 4 + 4);
+    if (start <= limit && limit <= (uint32_t)(offset - data)) {
+      const Slice filter = Slice(data + start, limit - start);
+
+      assert(table());
+      assert(table()->get_rep());
+      const FilterPolicy* const policy = table()->get_rep()->filter_policy;
+
+      const bool may_match = policy->KeyMayMatch(entry, filter);
+      if (may_match) {
+        PERF_COUNTER_ADD(bloom_sst_hit_count, 1);
+        return true;
+      } else {
+        PERF_COUNTER_ADD(bloom_sst_miss_count, 1);
+        return false;
+      }
+    } else if (start == limit) {
+      // Empty filters do not match any entries
+      return false;
+    }
+  }
+  return true;  // Errors are treated as potential matches
+}
+
+size_t BlockBasedFilterBlockReader::ApproximateMemoryUsage() const {
+  size_t usage = ApproximateFilterBlockMemoryUsage();
+#ifdef ROCKSDB_MALLOC_USABLE_SIZE
+  usage += malloc_usable_size(const_cast<BlockBasedFilterBlockReader*>(this));
+#else
+  usage += sizeof(*this);
+#endif  // ROCKSDB_MALLOC_USABLE_SIZE
+  return usage;
+}
+
+std::string BlockBasedFilterBlockReader::ToString() const {
+  CachableEntry<BlockContents> filter_block;
+
+  const Status s =
+      GetOrReadFilterBlock(false /* no_io */, nullptr /* get_context */,
+                           nullptr /* lookup_context */, &filter_block);
+  if (!s.ok()) {
+    return std::string("Unable to retrieve filter block");
+  }
+
+  assert(filter_block.GetValue());
+
+  const char* data = nullptr;
+  const char* offset = nullptr;
+  size_t num = 0;
+  size_t base_lg = 0;
+  if (!ParseFieldsFromBlock(*filter_block.GetValue(), &data, &offset, &num,
+                            &base_lg)) {
+    return std::string("Error parsing filter block");
+  }
+
+  std::string result;
+  result.reserve(1024);
+
+  std::string s_bo("Block offset"), s_hd("Hex dump"), s_fb("# filter blocks");
+  AppendItem(&result, s_fb, ROCKSDB_NAMESPACE::ToString(num));
+  AppendItem(&result, s_bo, s_hd);
+
+  for (size_t index = 0; index < num; index++) {
+    uint32_t start = DecodeFixed32(offset + index * 4);
+    uint32_t limit = DecodeFixed32(offset + index * 4 + 4);
+
+    if (start != limit) {
+      result.append(" filter block # " +
+                    ROCKSDB_NAMESPACE::ToString(index + 1) + "\n");
+      Slice filter = Slice(data + start, limit - start);
+      AppendItem(&result, start, filter.ToString(true));
+    }
+  }
+  return result;
+}
+
+}  // namespace ROCKSDB_NAMESPACE