(Republishing, or using this info in a commercial product/website, is prohibited without permission. All other uses are permitted. If in doubt, please ask.)

PREEMPTIVE_XE_SESSIONCOMMIT

(Back to main page…)

Description:

This wait type is when a thread switches to preemptive mode as part of committing changes to the list of Extended Event sessions on the instance.

(Books Online description: N/A)

Questions/comments on this wait type? Click here to send Paul an email, especially if you have any information to add to this topic.

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 542 in 2008 and 2008 R2, 590 in 2012, and 606 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.

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

  1. Committing the event session changes (in this case, as part of a CREATE EVENT SESSION operation)
  2. Committing the event session changes (in this case, as part of starting up the master database)

And other similar call stacks.

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

  1. SOS_Task::PopWait+b1
    SOS_ExternalAutoWait::~SOS_ExternalAutoWait+7a
    XE_Session::Commit+4ff
    XE_Session::Close+325
    XE_Session::Destroy+33
    XE_Engine::ReleaseObjectReference+8e
    XEventController::AlterEventSession+5ab
    CStmtCreateEventSession::XretExecute+126
    CMsqlExecContext::ExecuteStmts<0,1>+8bd
    CMsqlExecContext::FExecute+a58
    CSQLSource::Execute+86c
    process_request+a57
    process_commands+4a3
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+ab
  2. SOS_Task::PopWait+b1
    SOS_ExternalAutoWait::~SOS_ExternalAutoWait+7a
    XE_Session::Commit+4ff
    XEventController::VLR_StartXESession::CommitAndRelease+81
    XdesRMReadWrite::CommitAllVirtualLogRecs+e4
    XdesRMReadWrite::PreDestruct+23e
    XdesRMFull::~XdesRMFull+b2
    XdesRMFull::`vector deleting destructor’+14
    XactRM::SinglePhaseCommit+1e3
    XactRM::CommitInternal+472
    FullXactImp::Commit+33f
    CMsqlXactInternalReadWrite::Commit+19
    CMsqlXactImp::Commit+1d6
    CAutoMsqlXact::CommitNestedXact+bf
    FEventSessionStartup+2b9
    NotifyXEventMasterDbStarted+1bd
    NotifyMasterDatabaseReady+47
    StartUp::OpenDBsAndRecover+699
    StartUp::InitDBMS+aa
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+ab