74781a0c49
Summary: This patch adds three new MemTableRep's: UnsortedRep, PrefixHashRep, and VectorRep. UnsortedRep stores keys in an std::unordered_map of std::sets. When an iterator is requested, it dumps the keys into an std::set and iterates over that. VectorRep stores keys in an std::vector. When an iterator is requested, it creates a copy of the vector and sorts it using std::sort. The iterator accesses that new vector. PrefixHashRep stores keys in an unordered_map mapping prefixes to ordered sets. I also added one API change. I added a function MemTableRep::MarkImmutable. This function is called when the rep is added to the immutable list. It doesn't do anything yet, but it seems like that could be useful. In particular, for the vectorrep, it means we could elide the extra copy and just sort in place. The only reason I haven't done that yet is because the use of the ArenaAllocator complicates things (I can elaborate on this if needed). Test Plan: make -j32 check ./db_stress --memtablerep=vector ./db_stress --memtablerep=unsorted ./db_stress --memtablerep=prefixhash --prefix_size=10 Reviewers: dhruba, haobo, emayanke Reviewed By: dhruba CC: leveldb Differential Revision: https://reviews.facebook.net/D12117
69 lines
1.4 KiB
C++
69 lines
1.4 KiB
C++
// 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 "leveldb/slice_transform.h"
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#include "leveldb/slice.h"
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namespace leveldb {
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namespace {
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class FixedPrefixTransform : public SliceTransform {
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private:
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size_t prefix_len_;
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public:
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explicit FixedPrefixTransform(size_t prefix_len) : prefix_len_(prefix_len) { }
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virtual const char* Name() const {
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return "rocksdb.FixedPrefix";
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}
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virtual Slice Transform(const Slice& src) const {
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assert(InDomain(src));
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return Slice(src.data(), prefix_len_);
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}
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virtual bool InDomain(const Slice& src) const {
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return (src.size() >= prefix_len_);
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}
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virtual bool InRange(const Slice& dst) const {
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return (dst.size() == prefix_len_);
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}
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};
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class NoopTransform : public SliceTransform {
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public:
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explicit NoopTransform() { }
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virtual const char* Name() const {
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return "rocksdb.Noop";
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}
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virtual Slice Transform(const Slice& src) const {
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return src;
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}
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virtual bool InDomain(const Slice& src) const {
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return true;
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}
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virtual bool InRange(const Slice& dst) const {
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return true;
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}
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};
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}
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const SliceTransform* NewFixedPrefixTransform(size_t prefix_len) {
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return new FixedPrefixTransform(prefix_len);
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}
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const SliceTransform* NewNoopTransform() {
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return new NoopTransform;
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}
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} // namespace leveldb
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