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18dcf7f98d
Summary: Add PreReleaseCallback to be called at the end of WriteImpl but before publishing the sequence number. The callback is used in WritePrepareTxn to i) update the commit map, ii) update the last published sequence number in the 2nd write queue. It also ensures that all the commits will go to the 2nd queue. These changes will ensure that the commit map is updated before the sequence number is published and used by reading snapshots. If we use two write queues, the snapshots will use the seq number published by the 2nd queue. If we use one write queue (the default, the snapshots will use the last seq number in the memtable, which also indicates the last published seq number. Closes https://github.com/facebook/rocksdb/pull/3205 Differential Revision: D6438959 Pulled By: maysamyabandeh fbshipit-source-id: f8b6c434e94bc5f5ab9cb696879d4c23e2577ab9
31 lines
1.1 KiB
C++
31 lines
1.1 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 "rocksdb/status.h"
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namespace rocksdb {
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class DB;
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class PreReleaseCallback {
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public:
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virtual ~PreReleaseCallback() {}
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// Will be called while on the write thread after the write and before the
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// release of the sequence number. This is useful if any operation needs to be
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// done before the write gets visible to the readers, or if we want to reduce
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// the overhead of locking by updating something sequentially while we are on
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// the write thread. If the callback fails, this function returns a non-OK
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// status, the sequence number will not be released, and same status will be
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// propagated to all the writers in the write group.
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// seq is the sequence number that is used for this write and will be
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// released.
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virtual Status Callback(SequenceNumber seq) = 0;
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};
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} // namespace rocksdb
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