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SP_SERVER_DIAGNOSTICS_SLEEP

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Description:

This wait type is when the background system health monitor thread is waiting between checking whether to run the sp_server_diagnostics procedure. This was added for SQL Server 2012 to aid with automatic detection of failures to allow automatic failover with availability groups. You can read more about it:

  • In Books Online, here
  • On the PSS blog (long, detailed post) here

(Books Online description: N/A)

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Added in SQL Server version:

2012

Removed in SQL Server version:

N/A

Extended Events wait_type value:

The map_key value in sys.dm_xe_map_values is 736 in 2012 and 754 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 between checking whether to run sp_server_diagnostics_sleep

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

  1. SOS_Task::PostWait+90
    SOS_Task::Sleep+ea
    DiagnoseComponentMgr::Execute+f7f
    SystemHealthMonitor+12b
    SystemHealthMonitorThread+94
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+a8