4118e13330
Summary: Exposing persistent cache stats (counters) to the user via public API. Closes https://github.com/facebook/rocksdb/pull/1485 Differential Revision: D4155274 Pulled By: siying fbshipit-source-id: 30a9f50
66 lines
2.2 KiB
C++
66 lines
2.2 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same 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 <stdint.h>
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#include <memory>
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#include <string>
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#include "rocksdb/env.h"
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#include "rocksdb/slice.h"
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#include "rocksdb/statistics.h"
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#include "rocksdb/status.h"
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namespace rocksdb {
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// PersistentCache
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//
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// Persistent cache interface for caching IO pages on a persistent medium. The
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// cache interface is specifically designed for persistent read cache.
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class PersistentCache {
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public:
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typedef std::vector<std::map<std::string, double>> StatsType;
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virtual ~PersistentCache() {}
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// Insert to page cache
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//
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// page_key Identifier to identify a page uniquely across restarts
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// data Page data
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// size Size of the page
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virtual Status Insert(const Slice& key, const char* data,
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const size_t size) = 0;
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// Lookup page cache by page identifier
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//
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// page_key Page identifier
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// buf Buffer where the data should be copied
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// size Size of the page
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virtual Status Lookup(const Slice& key, std::unique_ptr<char[]>* data,
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size_t* size) = 0;
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// Is cache storing uncompressed data ?
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//
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// True if the cache is configured to store uncompressed data else false
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virtual bool IsCompressed() = 0;
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// Return stats as map of {string, double} per-tier
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//
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// Persistent cache can be initialized as a tier of caches. The stats are per
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// tire top-down
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virtual StatsType Stats() = 0;
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};
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// Factor method to create a new persistent cache
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Status NewPersistentCache(Env* const env, const std::string& path,
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const uint64_t size,
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const std::shared_ptr<Logger>& log,
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const bool optimized_for_nvm,
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std::shared_ptr<PersistentCache>* cache);
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} // namespace rocksdb
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