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f46464d383
Summary: This patch instruments the read path to verify each read value against an optional ReadCallback class. If the value is rejected, the reader moves on to the next value. The WritePreparedTxn makes use of this feature to skip sequence numbers that are not in the read snapshot. Closes https://github.com/facebook/rocksdb/pull/2850 Differential Revision: D5787375 Pulled By: maysamyabandeh fbshipit-source-id: 49d808b3062ab35e7ae98ad388f659757794184c
103 lines
3.4 KiB
C++
103 lines
3.4 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root 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 "db/range_del_aggregator.h"
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#include "db/read_callback.h"
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#include "rocksdb/env.h"
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#include "rocksdb/types.h"
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#include "table/block.h"
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namespace rocksdb {
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class MergeContext;
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class PinnedIteratorsManager;
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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, PinnableSlice* value, bool* value_found,
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MergeContext* merge_context, RangeDelAggregator* range_del_agg,
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Env* env, SequenceNumber* seq = nullptr,
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PinnedIteratorsManager* _pinned_iters_mgr = nullptr,
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ReadCallback* callback = nullptr);
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void MarkKeyMayExist();
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// Records this key, value, and any meta-data (such as sequence number and
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// state) into this GetContext.
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//
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// Returns True if more keys need to be read (due to merges) or
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// False if the complete value has been found.
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bool SaveValue(const ParsedInternalKey& parsed_key, const Slice& value,
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Cleanable* value_pinner = nullptr);
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// Simplified version of the previous function. Should only be used when we
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// know that the operation is a Put.
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void SaveValue(const Slice& value, SequenceNumber seq);
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GetState State() const { return state_; }
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RangeDelAggregator* range_del_agg() { return range_del_agg_; }
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PinnedIteratorsManager* pinned_iters_mgr() { return pinned_iters_mgr_; }
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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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// Do we need to fetch the SequenceNumber for this key?
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bool NeedToReadSequence() const { return (seq_ != nullptr); }
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bool sample() const { return sample_; }
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bool CheckCallback(SequenceNumber seq) {
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if (callback_) {
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return callback_->IsCommitted(seq);
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}
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return true;
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}
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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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PinnableSlice* pinnable_val_;
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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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RangeDelAggregator* range_del_agg_;
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Env* env_;
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// If a key is found, seq_ will be set to the SequenceNumber of most recent
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// write to the key or kMaxSequenceNumber if unknown
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SequenceNumber* seq_;
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std::string* replay_log_;
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// Used to temporarily pin blocks when state_ == GetContext::kMerge
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PinnedIteratorsManager* pinned_iters_mgr_;
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ReadCallback* callback_;
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bool sample_;
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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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Cleanable* value_pinner = nullptr);
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} // namespace rocksdb
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