mirror of
https://github.com/facebook/rocksdb.git
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d93812c9ae
Summary:
Preliminary support for iterator with user timestamp. Current implementation does not consider merge operator and reverse iterator. Auto compaction is also disabled in unit tests.
Create an iterator with timestamp.
```
...
read_opts.timestamp = &ts;
auto* iter = db->NewIterator(read_opts);
// target is key without timestamp.
for (iter->Seek(target); iter->Valid(); iter->Next()) {}
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {}
delete iter;
read_opts.timestamp = &ts1;
// lower_bound and upper_bound are without timestamp.
read_opts.iterate_lower_bound = &lower_bound;
read_opts.iterate_upper_bound = &upper_bound;
auto* iter1 = db->NewIterator(read_opts);
// Do Seek or SeekToFirst()
delete iter1;
```
Test plan (dev server)
```
$make check
```
Simple benchmarking (dev server)
1. The overhead introduced by this PR even when timestamp is disabled.
key size: 16 bytes
value size: 100 bytes
Entries: 1000000
Data reside in main memory, and try to stress iterator.
Repeated three times on master and this PR.
- Seek without next
```
./db_bench -db=/dev/shm/rocksdbtest-1000 -benchmarks=fillseq,seekrandom -enable_pipelined_write=false -disable_wal=true -format_version=3
```
master: 159047.0 ops/sec
this PR: 158922.3 ops/sec (2% drop in throughput)
- Seek and next 10 times
```
./db_bench -db=/dev/shm/rocksdbtest-1000 -benchmarks=fillseq,seekrandom -enable_pipelined_write=false -disable_wal=true -format_version=3 -seek_nexts=10
```
master: 109539.3 ops/sec
this PR: 107519.7 ops/sec (2% drop in throughput)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6255
Differential Revision: D19438227
Pulled By: riversand963
fbshipit-source-id: b66b4979486f8474619f4aa6bdd88598870b0746
77 lines
2.7 KiB
C++
77 lines
2.7 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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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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private:
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const Comparator* user_comparator_;
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};
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} // namespace ROCKSDB_NAMESPACE
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