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Description:
This wait type is when a thread is waiting for access to the queue of query store information that is asynchronously persisted to disk.
(Books Online description: N/A)
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Added in SQL Server version:
2016
Removed in SQL Server version:
N/A
Extended Events wait_type value:
The map_key value in sys.dm_xe_map_values is 1102 in 2016 RTM. After 2016 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 access to the queue (in this case, the background task that persists query store information to disk)
Abbreviated call stacks (list number matches known occurrences list):
- SOS_Task::PostWait+6f
SOS_Semaphore::Wait+16c
CQDSAsyncPersistManager::FnAsyncPersistTask+12a
SOS_Task::Param::Execute+231
SOS_Scheduler::RunTask+aa