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SLEEP_DBSTARTUP

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Description:

This wait type is when the main thread driving parallel database startup sleeps between checks to see if all the databases have started up. If you check the cumulative wait time for this wait type when the server has finished starting, that time is how long it took for all databases to be started in parallel.

(Books Online description: “Occurs during database startup while waiting for all databases to recover.”)

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Added in SQL Server version:

2008

Removed in SQL Server version:

N/A

Extended Events wait_type value:

The map_key value in sys.dm_xe_map_values is 102 in all versions through 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.

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. Sleeping between checks to see if all databases have been started

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

  1. SOS_Task::PostWait+9e
    EventInternal<SuspendQueueSLock>::Wait+1fb
    DBMgr::StartupDatabasesMainThread+54a
    DBMgr::StartupUserDatabases+5be
    StartUp::OpenDBsAndRecover+9c7
    StartUp::InitDBMS+aa
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+ab