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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
44 lines
1.3 KiB
C++
44 lines
1.3 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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//
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// Class for specifying user-defined functions which perform a
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// transformation on a slice. It is not required that every slice
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// belong to the domain and/or range of a function. Subclasses should
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// define InDomain and InRange to determine which slices are in either
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// of these sets respectively.
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#ifndef STORAGE_LEVELDB_INCLUDE_SLICE_TRANSFORM_H_
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#define STORAGE_LEVELDB_INCLUDE_SLICE_TRANSFORM_H_
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#include <string>
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namespace leveldb {
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class Slice;
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class SliceTransform {
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public:
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virtual ~SliceTransform() {};
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// Return the name of this transformation.
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virtual const char* Name() const = 0;
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// transform a src in domain to a dst in the range
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virtual Slice Transform(const Slice& src) const = 0;
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// determine whether this is a valid src upon the function applies
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virtual bool InDomain(const Slice& src) const = 0;
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// determine whether dst=Transform(src) for some src
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virtual bool InRange(const Slice& dst) const = 0;
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};
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extern const SliceTransform* NewFixedPrefixTransform(size_t prefix_len);
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extern const SliceTransform* NewNoopTransform();
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}
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#endif // STORAGE_LEVELDB_INCLUDE_SLICE_TRANSFORM_H_
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