ad96563b79
Summary: This patch allows an application to specify whether to use bufferedio, reads-via-mmaps and writes-via-mmaps per database. Earlier, there was a global static variable that was used to configure this functionality. The default setting remains the same (and is backward compatible): 1. use bufferedio 2. do not use mmaps for reads 3. use mmap for writes 4. use readaheads for reads needed for compaction I also added a parameter to db_bench to be able to explicitly specify whether to do readaheads for compactions or not. Test Plan: make check Reviewers: sheki, heyongqiang, MarkCallaghan Reviewed By: sheki CC: leveldb Differential Revision: https://reviews.facebook.net/D9429
70 lines
2.3 KiB
C++
70 lines
2.3 KiB
C++
// 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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// Thread-safe (provides internal synchronization)
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#ifndef STORAGE_LEVELDB_DB_TABLE_CACHE_H_
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#define STORAGE_LEVELDB_DB_TABLE_CACHE_H_
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#include <string>
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#include <stdint.h>
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#include "db/dbformat.h"
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#include "leveldb/env.h"
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#include "leveldb/cache.h"
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#include "leveldb/table.h"
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#include "port/port.h"
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#include "util/storage_options.h"
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namespace leveldb {
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class Env;
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class TableCache {
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public:
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TableCache(const std::string& dbname, const Options* options,
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const StorageOptions& storage_options, int entries);
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~TableCache();
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// Return an iterator for the specified file number (the corresponding
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// file length must be exactly "file_size" bytes). If "tableptr" is
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// non-nullptr, also sets "*tableptr" to point to the Table object
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// underlying the returned iterator, or nullptr if no Table object underlies
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// the returned iterator. The returned "*tableptr" object is owned by
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// the cache and should not be deleted, and is valid for as long as the
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// returned iterator is live.
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Iterator* NewIterator(const ReadOptions& options,
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const EnvOptions& toptions,
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uint64_t file_number,
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uint64_t file_size,
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Table** tableptr = nullptr);
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// If a seek to internal key "k" in specified file finds an entry,
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// call (*handle_result)(arg, found_key, found_value).
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Status Get(const ReadOptions& options,
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uint64_t file_number,
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uint64_t file_size,
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const Slice& k,
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void* arg,
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void (*handle_result)(void*, const Slice&, const Slice&, bool),
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bool* tableIO);
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// Evict any entry for the specified file number
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void Evict(uint64_t file_number);
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private:
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Env* const env_;
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const std::string dbname_;
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const Options* options_;
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const StorageOptions& storage_options_;
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std::shared_ptr<Cache> cache_;
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Status FindTable(const EnvOptions& toptions,
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uint64_t file_number, uint64_t file_size, Cache::Handle**,
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bool* tableIO = nullptr);
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};
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} // namespace leveldb
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#endif // STORAGE_LEVELDB_DB_TABLE_CACHE_H_
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