77ebc82b92
Summary: PreReleaseCallback meant to be called before the writes are visible to the readers. Since the sequence number is known after the WAL write, there is no reason to delay calling PreReleaseCallback to after the memtable write, which would complicates the reader's logic in presence of our memtable writes that are made visible by the other write thread. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5015 Differential Revision: D14221670 Pulled By: maysamyabandeh fbshipit-source-id: a504dd665cf923226d7af09cc8e9c7739a25edc6
33 lines
1.2 KiB
C++
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 to the WAL and
|
|
// before the write to memtable. 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, bool is_mem_disabled) = 0;
|
|
};
|
|
|
|
} // namespace rocksdb
|