fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
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73 lines
2.7 KiB
73 lines
2.7 KiB
// Copyright (c) 2013, 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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#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_NAMESPACE {
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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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using StatsType = std::vector<std::map<std::string, double>>;
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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 to copy (caller retains ownership)
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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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// True if the cache is configured to store serialized blocks, which are
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// potentially compressed and include a trailer (when SST format calls for
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// one). False if the cache stores uncompressed blocks (no trailer).
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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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virtual std::string GetPrintableOptions() const = 0;
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// Return a new numeric id. May be used by multiple clients who are
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// sharding the same persistent cache to partition the key space. Typically
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// the client will allocate a new id at startup and prepend the id to its
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// cache keys.
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virtual uint64_t NewId() = 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_NAMESPACE
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