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WAIT_XTP_RECOVERY

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Description:

Just as the description below states. This can occur during regular crash recovery, after a failover or restore, or during certain database state changes (e.g. offline to online, read-only to read-write, and vice-versa).

(Books Online description: “Occurs when database recovery is waiting for recovery of memory-optimized objects to finish.”)

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Added in SQL Server version:

2014

Removed in SQL Server version:

N/A

Extended Events wait_type value:

Maps to the XTP_RECOVERY map_value in sys.dm_xe_map_values.

The map_key value in sys.dm_xe_map_values is 923 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, but be aware that the database will not be available until the thread waiting for this wait type completes.

Known occurrences in SQL Server (list number matches call stack list):

  1. Waiting for recovery of memory-optimized objects to finish during a database startup

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

  1. SOS_Task::PostWait+9e
    EventInternal<SuspendQueueSLock>::Wait+2ca
    SOS_Task::WaitForDone+a0
    HkHostRestoreDbJoin+10c
    RecoveryUnit::CompleteRecovery+5aa
    RecoveryUnit::PhaseStart+87
    DBTABLE::StartupPostRecovery+4d
    DBTABLE::Startup+15c2
    DBMgr::StartupDB+6c6
    DBMgr::StartDBsInParallel+511
    DBMgr::ParallelDbStartupEntryPoint+10f
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+a8