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782a1590f9
Summary: Implementation of a table-level row cache. It only caches point queries done through the `DB::Get` interface, queries done through the `Iterator` interface will completely skip the cache. Supports snapshots and merge operations. Test Plan: Ran `make valgrind_check commit-prereq` Reviewers: igor, philipp, sdong Reviewed By: sdong Subscribers: dhruba Differential Revision: https://reviews.facebook.net/D39849
59 lines
1.8 KiB
C++
59 lines
1.8 KiB
C++
// Copyright (c) 2014, 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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#pragma once
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#include <string>
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#include "db/merge_context.h"
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#include "rocksdb/env.h"
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namespace rocksdb {
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class MergeContext;
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class GetContext {
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public:
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enum GetState {
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kNotFound,
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kFound,
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kDeleted,
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kCorrupt,
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kMerge // saver contains the current merge result (the operands)
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};
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GetContext(const Comparator* ucmp, const MergeOperator* merge_operator,
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Logger* logger, Statistics* statistics, GetState init_state,
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const Slice& user_key, std::string* ret_value, bool* value_found,
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MergeContext* merge_context, Env* env_);
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void MarkKeyMayExist();
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void SaveValue(const Slice& value);
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bool SaveValue(const ParsedInternalKey& parsed_key, const Slice& value);
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GetState State() const { return state_; }
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// If a non-null string is passed, all the SaveValue calls will be
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// logged into the string. The operations can then be replayed on
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// another GetContext with replayGetContextLog.
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void SetReplayLog(std::string* replay_log) { replay_log_ = replay_log; }
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private:
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const Comparator* ucmp_;
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const MergeOperator* merge_operator_;
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// the merge operations encountered;
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Logger* logger_;
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Statistics* statistics_;
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GetState state_;
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Slice user_key_;
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std::string* value_;
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bool* value_found_; // Is value set correctly? Used by KeyMayExist
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MergeContext* merge_context_;
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Env* env_;
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std::string* replay_log_;
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};
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void replayGetContextLog(const Slice& replay_log, const Slice& user_key,
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GetContext* get_context);
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} // namespace rocksdb
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