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QDS_ASYNC_QUEUE

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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.

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

  1. 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):

  1. SOS_Task::PostWait+6f
    SOS_Semaphore::Wait+16c
    CQDSAsyncPersistManager::FnAsyncPersistTask+12a
    SOS_Task::Param::Execute+231
    SOS_Scheduler::RunTask+aa