UCS_SESSION_REGISTRATION

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Description:

This wait type is when a thread is waiting for access to the list of Service Broker sessions so it can add or remove one.

(Books Online description: N/A)

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Added in SQL Server version:

2012

Removed in SQL Server version:

N/A

Extended Events wait_type value:

The map_key value in sys.dm_xe_map_values is 783 in 2012 and 801 in 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):

1. Waiting for access to the Service Broker session list (in this case, when registering a session as part of the underlying availability group transport)
2. Waiting for access to the Service Broker session list (in this case, when unregistering a session as part of the underlying availability group transport)

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

1. SOS_Task::PostWait+90
   EventInternal<SuspendQueueSLock>::Wait+25c
   SOS_Mutex::Wait+a7
   TAutoMutex<SOS_Mutex,1>::GetAccess+dd
   CSbServiceManager::RegisterSession+4b
   CSbTransmitter::RegisterSession+10c
   CHadrTransportReplica::SendDbMessage+994
   DbMgrPartner::SendNextMessage+32e
   DbMgrPartner::BuildAndSendLogMsg+7b
   DbMgrPartner::StartScans+24b
   HadrWorkItem::Execute+151
   HadrWorkRoutine+1c5
   SOS_Task::Param::Execute+21e
   SOS_Scheduler::RunTask+a8
2. SOS_Task::PostWait+90
   EventInternal<SuspendQueueSLock>::Wait+25c
   SOS_Mutex::Wait+a7
   TAutoMutex<SOS_Mutex,1>::GetAccess+dd
   CSbServiceManager::UnregisterSession+4c
   CSbTransmitter::UnregisterSession+10a
   CHadrTransportReplica::GetNextMessage+6ba
   CHadrSession::GetNextMessageToTransmit+1c
   CSbServiceManager::TransmitMessages+83
   CSbServiceManager::CBrokerService::Process+14f
   CSbDestinationManager::CDestination::Process+23a
   CSbDestinationManager::Process+c7
   CSbTransmitter::TransmitterThread+58c
   CSbTransmitter::BeginTransmitterThread+9
   CSbTask::TaskStart+14b
   CSbTask::BeginTaskStart+17
   SOS_Task::Param::Execute+21e
   SOS_Scheduler::RunTask+a8