mirror of https://github.com/facebook/rocksdb.git
38 lines
1.7 KiB
C++
38 lines
1.7 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"
|
|
#include "rocksdb/types.h"
|
|
|
|
namespace ROCKSDB_NAMESPACE {
|
|
|
|
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.
|
|
// If non-zero, log_number indicates the WAL log to which we wrote.
|
|
// index >= 0 specifies the order of callback in the same write thread.
|
|
// total > index specifies the total number of callbacks in the same write
|
|
// thread. Together with index, could be used to reduce the redundant
|
|
// operations among the callbacks.
|
|
virtual Status Callback(SequenceNumber seq, bool is_mem_disabled,
|
|
uint64_t log_number, size_t index, size_t total) = 0;
|
|
};
|
|
|
|
} // namespace ROCKSDB_NAMESPACE
|