rocksdb/db/pre_release_callback.h
Maysam Yabandeh 7429b20e39 WritePrepared Txn: fix race condition on publishing seq
Summary:
This commit fixes a race condition on calling SetLastPublishedSequence. The function must be called only from the 2nd write queue when two_write_queues is enabled. However there was a bug that would also call it from the main write queue if CommitTimeWriteBatch is provided to the commit request and yet use_only_the_last_commit_time_batch_for_recovery optimization is not enabled. To fix that we penalize the commit request in such cases by doing an additional write solely to publish the seq number from the 2nd queue.
Closes https://github.com/facebook/rocksdb/pull/3641

Differential Revision: D7361508

Pulled By: maysamyabandeh

fbshipit-source-id: bf8f7a27e5cccf5425dccbce25eb0032e8e5a4d7
2018-03-22 14:43:36 -07:00

33 lines
1.2 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include "rocksdb/status.h"
namespace rocksdb {
class DB;
class PreReleaseCallback {
public:
virtual ~PreReleaseCallback() {}
// Will be called while on the write thread after the write and before the
// release of the sequence number. This is useful if any operation needs to be
// done before the write gets visible to the readers, or if we want to reduce
// the overhead of locking by updating something sequentially while we are on
// the write thread. If the callback fails, this function returns a non-OK
// status, the sequence number will not be released, and same status will be
// propagated to all the writers in the write group.
// seq is the sequence number that is used for this write and will be
// released.
// is_mem_disabled is currently used for debugging purposes to assert that
// the callback is done from the right write queue.
virtual Status Callback(SequenceNumber seq, const bool is_mem_disabled) = 0;
};
} // namespace rocksdb