05e8854085
Summary: This diff introduces a new Merge operation into rocksdb. The purpose of this review is mostly getting feedback from the team (everyone please) on the design. Please focus on the four files under include/leveldb/, as they spell the client visible interface change. include/leveldb/db.h include/leveldb/merge_operator.h include/leveldb/options.h include/leveldb/write_batch.h Please go over local/my_test.cc carefully, as it is a concerete use case. Please also review the impelmentation files to see if the straw man implementation makes sense. Note that, the diff does pass all make check and truly supports forward iterator over db and a version of Get that's based on iterator. Future work: - Integration with compaction - A raw Get implementation I am working on a wiki that explains the design and implementation choices, but coding comes just naturally and I think it might be a good idea to share the code earlier. The code is heavily commented. Test Plan: run all local tests Reviewers: dhruba, heyongqiang Reviewed By: dhruba CC: leveldb, zshao, sheki, emayanke, MarkCallaghan Differential Revision: https://reviews.facebook.net/D9651
71 lines
2.4 KiB
C++
71 lines
2.4 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 "port/port.h"
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#include "table/table.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) 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* 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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