85584d497e
In particular, we add a new FilterPolicy class. An instance of this class can be supplied in Options when opening a database. If supplied, the instance is used to generate summaries of keys (e.g., a bloom filter) which are placed in sstables. These summaries are consulted by DB::Get() so we can avoid reading sstable blocks that are guaranteed to not contain the key we are looking for. This change provides one implementation of FilterPolicy based on bloom filters. Other changes: - Updated version number to 1.4. - Some build tweaks. - C binding for CompactRange. - A few more benchmarks: deleteseq, deleterandom, readmissing, seekrandom. - Minor .gitignore update.
62 lines
2.0 KiB
C++
62 lines
2.0 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/cache.h"
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#include "leveldb/table.h"
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#include "port/port.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, 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-NULL, also sets "*tableptr" to point to the Table object
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// underlying the returned iterator, or NULL 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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uint64_t file_number,
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uint64_t file_size,
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Table** tableptr = NULL);
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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&));
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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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Cache* cache_;
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Status FindTable(uint64_t file_number, uint64_t file_size, Cache::Handle**);
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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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