rocksdb/util/user_comparator_wrapper.h

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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 "monitoring/perf_context_imp.h"
#include "rocksdb/comparator.h"
namespace ROCKSDB_NAMESPACE {
// Wrapper of user comparator, with auto increment to
// perf_context.user_key_comparison_count.
class UserComparatorWrapper final : public Comparator {
public:
explicit UserComparatorWrapper(const Comparator* const user_cmp)
Iterator with timestamp (#6255) 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
2020-03-07 01:21:03 +01:00
: Comparator(user_cmp->timestamp_size()), user_comparator_(user_cmp) {}
~UserComparatorWrapper() = default;
const Comparator* user_comparator() const { return user_comparator_; }
int Compare(const Slice& a, const Slice& b) const override {
PERF_COUNTER_ADD(user_key_comparison_count, 1);
return user_comparator_->Compare(a, b);
}
bool Equal(const Slice& a, const Slice& b) const override {
PERF_COUNTER_ADD(user_key_comparison_count, 1);
return user_comparator_->Equal(a, b);
}
const char* Name() const override { return user_comparator_->Name(); }
void FindShortestSeparator(std::string* start,
const Slice& limit) const override {
return user_comparator_->FindShortestSeparator(start, limit);
}
void FindShortSuccessor(std::string* key) const override {
return user_comparator_->FindShortSuccessor(key);
}
const Comparator* GetRootComparator() const override {
return user_comparator_->GetRootComparator();
}
bool IsSameLengthImmediateSuccessor(const Slice& s,
const Slice& t) const override {
return user_comparator_->IsSameLengthImmediateSuccessor(s, t);
}
bool CanKeysWithDifferentByteContentsBeEqual() const override {
return user_comparator_->CanKeysWithDifferentByteContentsBeEqual();
}
Iterator with timestamp (#6255) 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
2020-03-07 01:21:03 +01:00
int CompareTimestamp(const Slice& ts1, const Slice& ts2) const override {
return user_comparator_->CompareTimestamp(ts1, ts2);
}
using Comparator::CompareWithoutTimestamp;
int CompareWithoutTimestamp(const Slice& a, bool a_has_ts, const Slice& b,
bool b_has_ts) const override {
PERF_COUNTER_ADD(user_key_comparison_count, 1);
return user_comparator_->CompareWithoutTimestamp(a, a_has_ts, b, b_has_ts);
}
private:
const Comparator* user_comparator_;
};
} // namespace ROCKSDB_NAMESPACE