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FT_IFTS_RWLOCK

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Description:

This wait type is when a thread is waiting for synchronization on the full-text background task queue so it can remove an item from it.

(Books Online description: “Full-text is waiting on internal synchronization. Documented for informational purposes only. Not supported. Future compatibility is not guaranteed.”)

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Added in SQL Server version:

2008

Removed in SQL Server version:

N/A

Extended Events wait_type value:

Maps to the FT_RWLOCK map_value in sys.dm_xe_map_values (thanks to Jonathan’s post here).

The map_key value in sys.dm_xe_map_values is 587 in 2008 and 2008 R2, 637 in 2012, and 653 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 full-text background task queue

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

  1. SOS_Task::PostWait+90
    EventInternal<SuspendQueueSLock>::Wait+2c6
    SOS_RWLock::GetLongWait+10b
    IFTSAutoRWLock::IFTSAutoRWLock+1e4
    CFTScheduler::FGetWorkItem+37
    IFTSWorkerTask+164
    SystemTaskEntryPoint+431
    SOS_Scheduler::SystemTimerEntryPoint+132
    SOS_Scheduler::SystemTimerInit+61
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+a8