Summary: Our valgrind continuous test found an interesting leak which got introduced in #3614. We were adding the prefix key before saving the previous prefix start offset, due to which previous prefix offset is always incorrect. Fixed it by saving the the previous sate before adding the key. Closes https://github.com/facebook/rocksdb/pull/3660 Differential Revision: D7418698 Pulled By: sagar0 fbshipit-source-id: 9933685f943cf2547ed5c553f490035a2fa785cf
257 lines
8.1 KiB
C++
257 lines
8.1 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include "table/block_based_filter_block.h"
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#include <algorithm>
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#include "db/dbformat.h"
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#include "monitoring/perf_context_imp.h"
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#include "rocksdb/filter_policy.h"
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#include "util/coding.h"
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#include "util/string_util.h"
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namespace rocksdb {
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namespace {
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void AppendItem(std::string* props, const std::string& key,
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const std::string& value) {
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char cspace = ' ';
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std::string value_str("");
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size_t i = 0;
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const size_t dataLength = 64;
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const size_t tabLength = 2;
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const size_t offLength = 16;
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value_str.append(&value[i], std::min(size_t(dataLength), value.size()));
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i += dataLength;
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while (i < value.size()) {
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value_str.append("\n");
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value_str.append(offLength, cspace);
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value_str.append(&value[i], std::min(size_t(dataLength), value.size() - i));
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i += dataLength;
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}
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std::string result("");
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if (key.size() < (offLength - tabLength))
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result.append(size_t((offLength - tabLength)) - key.size(), cspace);
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result.append(key);
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props->append(result + ": " + value_str + "\n");
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}
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template <class TKey>
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void AppendItem(std::string* props, const TKey& key, const std::string& value) {
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std::string key_str = rocksdb::ToString(key);
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AppendItem(props, key_str, value);
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}
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} // namespace
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// See doc/table_format.txt for an explanation of the filter block format.
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// Generate new filter every 2KB of data
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static const size_t kFilterBaseLg = 11;
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static const size_t kFilterBase = 1 << kFilterBaseLg;
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BlockBasedFilterBlockBuilder::BlockBasedFilterBlockBuilder(
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const SliceTransform* prefix_extractor,
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const BlockBasedTableOptions& table_opt)
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: policy_(table_opt.filter_policy.get()),
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prefix_extractor_(prefix_extractor),
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whole_key_filtering_(table_opt.whole_key_filtering),
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prev_prefix_start_(0),
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prev_prefix_size_(0),
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num_added_(0) {
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assert(policy_);
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}
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void BlockBasedFilterBlockBuilder::StartBlock(uint64_t block_offset) {
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uint64_t filter_index = (block_offset / kFilterBase);
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assert(filter_index >= filter_offsets_.size());
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while (filter_index > filter_offsets_.size()) {
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GenerateFilter();
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}
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}
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void BlockBasedFilterBlockBuilder::Add(const Slice& key) {
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if (prefix_extractor_ && prefix_extractor_->InDomain(key)) {
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AddPrefix(key);
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}
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if (whole_key_filtering_) {
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AddKey(key);
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}
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}
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// Add key to filter if needed
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inline void BlockBasedFilterBlockBuilder::AddKey(const Slice& key) {
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num_added_++;
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start_.push_back(entries_.size());
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entries_.append(key.data(), key.size());
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}
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// Add prefix to filter if needed
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inline void BlockBasedFilterBlockBuilder::AddPrefix(const Slice& key) {
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// get slice for most recently added entry
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Slice prev;
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if (prev_prefix_size_ > 0) {
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prev = Slice(entries_.data() + prev_prefix_start_, prev_prefix_size_);
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}
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Slice prefix = prefix_extractor_->Transform(key);
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// insert prefix only when it's different from the previous prefix.
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if (prev.size() == 0 || prefix != prev) {
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prev_prefix_start_ = entries_.size();
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prev_prefix_size_ = prefix.size();
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AddKey(prefix);
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}
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}
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Slice BlockBasedFilterBlockBuilder::Finish(const BlockHandle& /*tmp*/,
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Status* status) {
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// In this impl we ignore BlockHandle
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*status = Status::OK();
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if (!start_.empty()) {
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GenerateFilter();
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}
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// Append array of per-filter offsets
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const uint32_t array_offset = static_cast<uint32_t>(result_.size());
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for (size_t i = 0; i < filter_offsets_.size(); i++) {
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PutFixed32(&result_, filter_offsets_[i]);
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}
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PutFixed32(&result_, array_offset);
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result_.push_back(kFilterBaseLg); // Save encoding parameter in result
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return Slice(result_);
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}
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void BlockBasedFilterBlockBuilder::GenerateFilter() {
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const size_t num_entries = start_.size();
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if (num_entries == 0) {
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// Fast path if there are no keys for this filter
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filter_offsets_.push_back(static_cast<uint32_t>(result_.size()));
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return;
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}
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// Make list of keys from flattened key structure
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start_.push_back(entries_.size()); // Simplify length computation
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tmp_entries_.resize(num_entries);
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for (size_t i = 0; i < num_entries; i++) {
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const char* base = entries_.data() + start_[i];
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size_t length = start_[i + 1] - start_[i];
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tmp_entries_[i] = Slice(base, length);
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}
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// Generate filter for current set of keys and append to result_.
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filter_offsets_.push_back(static_cast<uint32_t>(result_.size()));
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policy_->CreateFilter(&tmp_entries_[0], static_cast<int>(num_entries),
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&result_);
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tmp_entries_.clear();
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entries_.clear();
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start_.clear();
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prev_prefix_start_ = 0;
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prev_prefix_size_ = 0;
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}
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BlockBasedFilterBlockReader::BlockBasedFilterBlockReader(
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const SliceTransform* prefix_extractor,
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const BlockBasedTableOptions& table_opt, bool _whole_key_filtering,
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BlockContents&& contents, Statistics* stats)
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: FilterBlockReader(contents.data.size(), stats, _whole_key_filtering),
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policy_(table_opt.filter_policy.get()),
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prefix_extractor_(prefix_extractor),
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data_(nullptr),
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offset_(nullptr),
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num_(0),
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base_lg_(0),
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contents_(std::move(contents)) {
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assert(policy_);
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size_t n = contents_.data.size();
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if (n < 5) return; // 1 byte for base_lg_ and 4 for start of offset array
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base_lg_ = contents_.data[n - 1];
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uint32_t last_word = DecodeFixed32(contents_.data.data() + n - 5);
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if (last_word > n - 5) return;
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data_ = contents_.data.data();
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offset_ = data_ + last_word;
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num_ = (n - 5 - last_word) / 4;
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}
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bool BlockBasedFilterBlockReader::KeyMayMatch(
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const Slice& key, uint64_t block_offset, const bool /*no_io*/,
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const Slice* const /*const_ikey_ptr*/) {
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assert(block_offset != kNotValid);
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if (!whole_key_filtering_) {
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return true;
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}
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return MayMatch(key, block_offset);
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}
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bool BlockBasedFilterBlockReader::PrefixMayMatch(
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const Slice& prefix, uint64_t block_offset, const bool /*no_io*/,
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const Slice* const /*const_ikey_ptr*/) {
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assert(block_offset != kNotValid);
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if (!prefix_extractor_) {
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return true;
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}
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return MayMatch(prefix, block_offset);
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}
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bool BlockBasedFilterBlockReader::MayMatch(const Slice& entry,
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uint64_t block_offset) {
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uint64_t index = block_offset >> base_lg_;
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if (index < num_) {
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uint32_t start = DecodeFixed32(offset_ + index * 4);
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uint32_t limit = DecodeFixed32(offset_ + index * 4 + 4);
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if (start <= limit && limit <= (uint32_t)(offset_ - data_)) {
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Slice filter = Slice(data_ + start, limit - start);
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bool const may_match = policy_->KeyMayMatch(entry, filter);
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if (may_match) {
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PERF_COUNTER_ADD(bloom_sst_hit_count, 1);
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return true;
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} else {
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PERF_COUNTER_ADD(bloom_sst_miss_count, 1);
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return false;
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}
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} else if (start == limit) {
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// Empty filters do not match any entries
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return false;
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}
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}
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return true; // Errors are treated as potential matches
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}
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size_t BlockBasedFilterBlockReader::ApproximateMemoryUsage() const {
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return num_ * 4 + 5 + (offset_ - data_);
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}
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std::string BlockBasedFilterBlockReader::ToString() const {
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std::string result;
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result.reserve(1024);
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std::string s_bo("Block offset"), s_hd("Hex dump"), s_fb("# filter blocks");
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AppendItem(&result, s_fb, rocksdb::ToString(num_));
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AppendItem(&result, s_bo, s_hd);
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for (size_t index = 0; index < num_; index++) {
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uint32_t start = DecodeFixed32(offset_ + index * 4);
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uint32_t limit = DecodeFixed32(offset_ + index * 4 + 4);
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if (start != limit) {
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result.append(" filter block # " + rocksdb::ToString(index + 1) + "\n");
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Slice filter = Slice(data_ + start, limit - start);
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AppendItem(&result, start, filter.ToString(true));
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}
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}
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return result;
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}
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} // namespace rocksdb
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