9eb3e1f77d
Summary: Use delete to disable automatic generated methods instead of private, and put the constructor together for more clear.This modification cause the unused field warning, so add unused attribute to disable this warning. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5009 Differential Revision: D17288733 fbshipit-source-id: 8a767ce096f185f1db01bd28fc88fef1cdd921f3
75 lines
2.9 KiB
C++
75 lines
2.9 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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// 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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#pragma once
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#include "rocksdb/stats_history.h"
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namespace rocksdb {
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// InMemoryStatsHistoryIterator can be used to access stats history that was
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// stored by an in-memory two level std::map(DBImpl::stats_history_). It keeps
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// a copy of the stats snapshot (in stats_map_) that is currently being pointed
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// to, which allows the iterator to access the stats snapshot even when
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// the background garbage collecting thread purges it from the source of truth
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// (`DBImpl::stats_history_`). In that case, the iterator will continue to be
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// valid until a call to `Next()` returns no result and invalidates it. In
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// some extreme cases, the iterator may also return fragmented segments of
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// stats snapshots due to long gaps between `Next()` calls and interleaved
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// garbage collection.
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class InMemoryStatsHistoryIterator final : public StatsHistoryIterator {
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public:
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// Setup InMemoryStatsHistoryIterator to return stats snapshots between
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// seconds timestamps [start_time, end_time)
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InMemoryStatsHistoryIterator(uint64_t start_time, uint64_t end_time,
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DBImpl* db_impl)
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: start_time_(start_time),
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end_time_(end_time),
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valid_(true),
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db_impl_(db_impl) {
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AdvanceIteratorByTime(start_time_, end_time_);
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}
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// no copying allowed
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InMemoryStatsHistoryIterator(const InMemoryStatsHistoryIterator&) = delete;
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void operator=(const InMemoryStatsHistoryIterator&) = delete;
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InMemoryStatsHistoryIterator(InMemoryStatsHistoryIterator&&) = delete;
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InMemoryStatsHistoryIterator& operator=(InMemoryStatsHistoryIterator&&) =
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delete;
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~InMemoryStatsHistoryIterator() override;
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bool Valid() const override;
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Status status() const override;
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// Move to the next stats snapshot currently available
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// This function may invalidate the iterator
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// REQUIRES: Valid()
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void Next() override;
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// REQUIRES: Valid()
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uint64_t GetStatsTime() const override;
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// This function is idempotent
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// REQUIRES: Valid()
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const std::map<std::string, uint64_t>& GetStatsMap() const override;
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private:
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// advance the iterator to the next stats history record with timestamp
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// between [start_time, end_time)
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void AdvanceIteratorByTime(uint64_t start_time, uint64_t end_time);
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uint64_t time_;
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uint64_t start_time_;
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uint64_t end_time_;
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std::map<std::string, uint64_t> stats_map_;
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Status status_;
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bool valid_;
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DBImpl* db_impl_;
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};
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} // namespace rocksdb
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