82b3888433
Summary: This PR does the following: - Enable backward iteration for keys with user-defined timestamp. Note that merge, single delete, range delete are not supported yet. - Introduces a new helper API `Comparator::EqualWithoutTimestamp()`. - Fix a typo in `SetTimestamp()`. - Add/update unit tests Run db_bench (built with DEBUG_LEVEL=0) to demonstrate that no overhead is introduced for CPU-intensive workloads with a lot of `Prev()`. Also provided results of iterating keys with timestamps. 1. Disable timestamp, run: ``` ./db_bench -db=/dev/shm/rocksdb -disable_wal=1 -benchmarks=fillseq,seekrandom[-W1-X6] -reverse_iterator=1 -seek_nexts=5 ``` Results: > Baseline > - seekrandom [AVG 6 runs] : 96115 ops/sec; 53.2 MB/sec > - seekrandom [MEDIAN 6 runs] : 98075 ops/sec; 54.2 MB/sec > > This PR > - seekrandom [AVG 6 runs] : 95521 ops/sec; 52.8 MB/sec > - seekrandom [MEDIAN 6 runs] : 96338 ops/sec; 53.3 MB/sec 2. Enable timestamp, run: ``` ./db_bench -user_timestamp_size=8 -db=/dev/shm/rocksdb -disable_wal=1 -benchmarks=fillseq,seekrandom[-W1-X6] -reverse_iterator=1 -seek_nexts=5 ``` Result: > Baseline: not supported > > This PR > - seekrandom [AVG 6 runs] : 90514 ops/sec; 50.1 MB/sec > - seekrandom [MEDIAN 6 runs] : 90834 ops/sec; 50.2 MB/sec Pull Request resolved: https://github.com/facebook/rocksdb/pull/8035 Reviewed By: ltamasi Differential Revision: D26926668 Pulled By: riversand963 fbshipit-source-id: 95330cc2242397c03e09d29e5417dfb0adc98ef5
85 lines
3.0 KiB
C++
85 lines
3.0 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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// Copyright (c) 2011 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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#pragma once
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#include "monitoring/perf_context_imp.h"
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#include "rocksdb/comparator.h"
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namespace ROCKSDB_NAMESPACE {
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// Wrapper of user comparator, with auto increment to
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// perf_context.user_key_comparison_count.
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class UserComparatorWrapper final : public Comparator {
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public:
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// `UserComparatorWrapper`s constructed with the default constructor are not
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// usable and will segfault on any attempt to use them for comparisons.
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UserComparatorWrapper() : user_comparator_(nullptr) {}
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explicit UserComparatorWrapper(const Comparator* const user_cmp)
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: Comparator(user_cmp->timestamp_size()), user_comparator_(user_cmp) {}
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~UserComparatorWrapper() = default;
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const Comparator* user_comparator() const { return user_comparator_; }
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int Compare(const Slice& a, const Slice& b) const override {
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PERF_COUNTER_ADD(user_key_comparison_count, 1);
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return user_comparator_->Compare(a, b);
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}
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bool Equal(const Slice& a, const Slice& b) const override {
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PERF_COUNTER_ADD(user_key_comparison_count, 1);
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return user_comparator_->Equal(a, b);
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}
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const char* Name() const override { return user_comparator_->Name(); }
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void FindShortestSeparator(std::string* start,
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const Slice& limit) const override {
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return user_comparator_->FindShortestSeparator(start, limit);
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}
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void FindShortSuccessor(std::string* key) const override {
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return user_comparator_->FindShortSuccessor(key);
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}
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const Comparator* GetRootComparator() const override {
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return user_comparator_->GetRootComparator();
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}
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bool IsSameLengthImmediateSuccessor(const Slice& s,
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const Slice& t) const override {
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return user_comparator_->IsSameLengthImmediateSuccessor(s, t);
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}
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bool CanKeysWithDifferentByteContentsBeEqual() const override {
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return user_comparator_->CanKeysWithDifferentByteContentsBeEqual();
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}
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int CompareTimestamp(const Slice& ts1, const Slice& ts2) const override {
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return user_comparator_->CompareTimestamp(ts1, ts2);
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}
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using Comparator::CompareWithoutTimestamp;
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int CompareWithoutTimestamp(const Slice& a, bool a_has_ts, const Slice& b,
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bool b_has_ts) const override {
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PERF_COUNTER_ADD(user_key_comparison_count, 1);
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return user_comparator_->CompareWithoutTimestamp(a, a_has_ts, b, b_has_ts);
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}
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bool EqualWithoutTimestamp(const Slice& a, const Slice& b) const override {
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return user_comparator_->EqualWithoutTimestamp(a, b);
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}
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private:
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const Comparator* user_comparator_;
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};
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} // namespace ROCKSDB_NAMESPACE
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