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Description:
This wait type is just as the Books Online entry describes.
(Books Online description: “A background task that processes Windows Server Failover Clustering notifications is waiting for the next notification. Internal use only.”)
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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 836 in 2012 and 855 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.
This wait type is one that I usually filter out as a benign wait when doing wait statistics analysis.
Known occurrences in SQL Server (list number matches call stack list):
- Waiting for a failover cluster notification
Abbreviated call stacks (list number matches known occurrences list):
- SOS_Task::PostWait+90
EventInternal<SuspendQueueSLock>::Wait+2c6
ResQueueBase::Dequeue+1cf
CHadrNotificationWorker::RunThread+151
SOS_Task::Param::Execute+21e
SOS_Scheduler::RunTask+a8