c24d8c4e90
Summary: Adapting table cache to column families is interesting. We want table cache to be global LRU, so if some column families are use not as often as others, we want them to be evicted from cache. However, current TableCache object also constructs tables on its own. If table is not found in the cache, TableCache automatically creates new table. We want each column family to be able to specify different table factory. To solve the problem, we still have a single LRU, but we provide the LRUCache object to TableCache on construction. We have one TableCache per column family, but the underyling cache is shared by all TableCache objects. This allows us to have a global LRU, but still be able to support different table factories for different column families. Also, in the future it will also be able to support different directories for different column families. Test Plan: make check Reviewers: dhruba, haobo, kailiu, sdong CC: leveldb Differential Revision: https://reviews.facebook.net/D15915
81 lines
3.1 KiB
C++
81 lines
3.1 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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//
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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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// Thread-safe (provides internal synchronization)
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#pragma once
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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 "rocksdb/env.h"
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#include "rocksdb/cache.h"
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#include "port/port.h"
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#include "rocksdb/table.h"
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namespace rocksdb {
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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* db_options,
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const ColumnFamilyOptions* cf_options,
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const EnvOptions& storage_options, Cache* cache);
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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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TableReader** table_reader_ptr = nullptr,
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bool for_compaction = false);
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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) repeatedly until
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// it returns false.
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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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bool (*handle_result)(void*, const Slice&, const Slice&, bool),
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bool* table_io,
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void (*mark_key_may_exist)(void*) = nullptr);
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// Determine whether the table may contain the specified prefix. If
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// the table index of blooms are not in memory, this may cause an I/O
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bool PrefixMayMatch(const ReadOptions& options, uint64_t file_number,
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uint64_t file_size, const Slice& internal_prefix,
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bool* table_io);
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// Evict any entry for the specified file number
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static void Evict(Cache* cache, 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* db_options_;
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const ColumnFamilyOptions* cf_options_;
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const EnvOptions& storage_options_;
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Cache* const cache_;
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Status FindTable(const EnvOptions& toptions, uint64_t file_number,
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uint64_t file_size, Cache::Handle**, bool* table_io=nullptr,
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const bool no_io = false);
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};
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} // namespace rocksdb
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