Information About Waits Stats in SQL Server PREEMPTIVE Operating System Related Waits

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SQL Server internally uses worker threads to execute SQL queries sent by various applications. While threads are executing they may be either running on CPU processing the request or would be waiting on a certain resource or waiting in waiting for its chance to run on CPU. SQL Server assigns a certain wait type to the worker thread that is waiting.

If a query is taking long time to complete, we can look at the query sessions wait type to get an understanding of what kind of resource it is the query waiting for and take appropriate action to avoid the queries to wait, thus making the queries complete fast.

Below are some of the SQL Server Wait Types related to PREEMPTIVE Operating System related waits.

PREEMPTIVE_ABR
Identified for informational purposes only. Not supported. Future compatibility is not guaranteed.

PREEMPTIVE_AUDIT_ACCESS_EVENTLOG
Occurs when the SQL Server Operating System (SQLOS) scheduler switches to preemptive mode to write an audit event to the Windows event log.

PREEMPTIVE_AUDIT_ACCESS_SECLOG
Occurs when the SQLOS scheduler switches to preemptive mode to write an audit event to the Windows Security log.

PREEMPTIVE_CLOSEBACKUPMEDIA
Occurs when the SQLOS scheduler switches to preemptive mode to close backup media.

PREEMPTIVE_CLOSEBACKUPTAPE
Occurs when the SQLOS scheduler switches to preemptive mode to close a tape backup device.

PREEMPTIVE_CLOSEBACKUPVDIDEVICE
Occurs when the SQLOS scheduler switches to preemptive mode to close a virtual backup device.

PREEMPTIVE_CLUSAPI_CLUSTERRESOURCECONTROL
Occurs when the SQLOS scheduler switches to preemptive mode to perform Windows failover cluster operations.

PREEMPTIVE_COM_COCREATEINSTANCE
Occurs when the SQLOS scheduler switches to preemptive mode to create a COM object.

PREEMPTIVE_HADR_LEASE_MECHANISM
AlwaysOn Availability Groups lease manager scheduling for CSS diagnostics.
Applies to: SQL Server 2012 through SQL Server 2014.

PREEMPTIVE_SOSTESTING
Identified for informational purposes only. Not supported. Future compatibility is not guaranteed.

PREEMPTIVE_STRESSDRIVER
Identified for informational purposes only. Not supported. Future compatibility is not guaranteed.

PREEMPTIVE_TESTING
Identified for informational purposes only. Not supported. Future compatibility is not guaranteed.

PREEMPTIVE_XETESTING
Identified for informational purposes only. Not supported. Future compatibility is not guaranteed.

This is applicable on below versions of SQL Server

SQL Server 2005
SQL Server 2008 R2
SQL Server 2012
SQL Server 2014

Hope this was helpful.

Thanks,
SQLServerF1 Team
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