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FT_IFTS_SCHEDULER_IDLE_WAIT

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Description:

This wait type is when a thread is waiting for some work to be entered on the full-text search background task queue.

(Books Online description: “Full-text scheduler sleep wait type. The scheduler is idle.”)

Questions/comments on this wait type? Click here to send Paul an email, especially if you have any information to add to this topic.

Added in SQL Server version:

2008

Removed in SQL Server version:

N/A

Extended Events wait_type value:

Maps to the FT_SCHEDULER_IDLE_WAIT 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 594 in 2008 and 2008 R2, 645 in 2012, and 661 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 and it can be safely ignored.

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):

  1. Waiting for full-text work to be queued
  2. Waiting for full-text work to be queued

And other similar call stacks.

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

  1. SOS_Task::PostWait+90
    EventInternal<SuspendQueueSLock>::Wait+25c
    CFTScheduler::Wait+41
    FTSchedulerTask+260
    SOS_Scheduler::SystemTimerEntryPoint+132
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+a8
  2. SOS_Task::PostWait+90
    EventInternal<SuspendQueueSLock>::Wait+25c
    CFTScheduler::WaitForNotification+41
    CFTWIAutoCrawlMonitor::ExecuteImpl+58
    IFTSWorkerTask+37c
    SystemTaskEntryPoint+450
    SOS_Scheduler::SystemTimerEntryPoint+132
    SOS_Scheduler::SystemTimerInit+8e
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+a8