mirror of https://github.com/facebook/rocksdb.git
46 lines
1.6 KiB
C++
46 lines
1.6 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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//
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// Compression context cache allows to cache compression/uncompression contexts
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// This helps with Random Read latencies and reduces CPU utilization
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// Caching is implemented using CoreLocal facility. Compression/Uncompression
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// instances are cached on a per core basis using CoreLocalArray. A borrowed
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// instance is atomically replaced with a sentinel value for the time of being
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// used. If it turns out that another thread is already makes use of the
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// instance we still create one on the heap which is later is destroyed.
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#pragma once
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#include <stdint.h>
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namespace rocksdb {
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class ZSTDUncompressCachedData;
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class CompressionContextCache {
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public:
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// Singleton
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static CompressionContextCache* Instance();
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static void InitSingleton();
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CompressionContextCache(const CompressionContextCache&) = delete;
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CompressionContextCache& operator=(const CompressionContextCache&) = delete;
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ZSTDUncompressCachedData GetCachedZSTDUncompressData();
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void ReturnCachedZSTDUncompressData(int64_t idx);
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private:
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// Singleton
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CompressionContextCache();
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~CompressionContextCache();
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class Rep;
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Rep* rep_;
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};
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} // namespace rocksdb
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