DBMIRROR_DBM_MUTEX

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Description:

This wait type is when a thread is waiting for parallel threads that are replaying one or more log records on the mirror database in a database mirroring partnership. This wait only occurs on the mirror server.

(Books Online description: “Identified for informational purposes only. Not supported. Future compatibility is not guaranteed.”)

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Added in SQL Server version:

Pre-2005/2005

Removed in SQL Server version:

N/A

Extended Events wait_type value:

The map_key value in sys.dm_xe_map_values is 137 in 2008 and 2008 R2, and 141 in 2012 and 2014 RTM. After 2014 RTM, you must check the DMV to get the latest value as some map_key values have changed in later builds.

Other information:

I have not seen this wait type be a noticeable contention point.

Known occurrences in SQL Server (list number matches call stack list):

In all cases, waiting for parallel redo threads to complete an operation.

And many more similar call stacks.

Abbreviated call stacks (list number matches known occurrences list):

1. SOS_Task::PostWait+9e
   EventInternal<SuspendQueueSLock>::Wait+1fb
   DBMRedoManager::StartParallelRedoThreads+193
   LsBackupStateMachine::ChangeState+77
   LsBackupStateMachine::ChooseRealtimeShipping+19a
   LsBackupStateMachine::WaitingForEndOfLogAction+14d
   LsStateMachineBase::PostEvent+1d7
   LsStateMachineBase::PostEvent+8a
   LsDatabaseStateMachine::BackupAction+4a2
   LsStateMachineBase::PostEvent+1d7
   LsStateMachineBase::PostEvent+8a
   LsStateMachineBase::EscalateEvent+96
   LsStateMachineBase::PostEvent+1d7
   LsStateMgr::ProcessEvents+113
   DbmDatabaseStateMgr::MasterThreadRoutine+303
   SOS_Task::Param::Execute+21e
   SOS_Scheduler::RunTask+a8
2. SOS_Task::PostWait+9e
   EventInternal<SuspendQueueSLock>::Wait+1fb
   DBMRedoManager::WaitForRedo+171
   LsMgr::ProcessLogStream+bef
   LsMgr::ProcessLogStreamResponse+6e
   LsWorkRequest::Execute+47
   LsWorker::ThreadRoutine+152
   LsWorker::ThreadRoutine+1c7
   SOS_Task::Param::Execute+21e
   SOS_Scheduler::RunTask+a8
3. SOS_Task::PostWait+9e
   EventInternal<SuspendQueueSLock>::Wait+1fb
   DBMRedoManager::ApplyLogSegment+5ee
   DBMRedoManager::Execute+5e7
   SubprocEntrypoint+a7f
   SOS_Task::Param::Execute+21e
   SOS_Scheduler::RunTask+a8