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SLEEP_MASTERDBREADY

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Description:

This wait type is when a thread is waiting for the master database to start during instance startup. There will be exactly one of these waits and its wait time is how long the master database took to start.

(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 106 in 2012 and 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. Waiting for the master database to start during instance startup

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

  1. SOS_Task::PostWait+9e
    EventInternal<SuspendQueueSLock>::Wait+1fb
    StartUp::WaitForMasterDbReady+39
    StartUp::StartModelAndTempdb+380
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+ab