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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.”)
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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_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):
- Waiting for full-text work to be queued
- Waiting for full-text work to be queued
And other similar call stacks.
Abbreviated call stacks (list number matches known occurrences list):
- 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 - 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