mirror of https://github.com/facebook/rocksdb.git
45 lines
1.3 KiB
C++
45 lines
1.3 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 <stdint.h>
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#include <atomic>
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#include <mutex>
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#include "util/autovector.h"
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namespace rocksdb {
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class ColumnFamilyData;
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// Similar to FlushScheduler, TrimHistoryScheduler is a FIFO queue that keeps
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// track of column families whose flushed immutable memtables may need to be
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// removed (aka trimmed). The actual trimming may be slightly delayed. Due to
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// the use of the mutex and atomic variable, ScheduleWork,
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// TakeNextColumnFamily, and, Empty can be called concurrently.
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class TrimHistoryScheduler {
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public:
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TrimHistoryScheduler() : is_empty_(true) {}
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// When a column family needs history trimming, add cfd to the FIFO queue
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void ScheduleWork(ColumnFamilyData* cfd);
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// Remove the column family from the queue, the caller is responsible for
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// calling `MemtableList::TrimHistory`
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ColumnFamilyData* TakeNextColumnFamily();
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bool Empty();
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void Clear();
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// Not on critical path, use mutex to ensure thread safety
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private:
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std::atomic<bool> is_empty_;
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autovector<ColumnFamilyData*> cfds_;
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std::mutex checking_mutex_;
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};
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} // namespace rocksdb
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