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CLR_AUTO_EVENT

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Description:

This wait type is described below, and is really just a CLR worker thread waiting for something to do. You can read more about this on the PSS blog here.

(Books Online description: “Occurs when a task is currently performing common language runtime (CLR) execution and is waiting for a particular autoevent to be initiated. Long waits are typical, and do not indicate a problem.”)

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:

Pre-2005/2005

Removed in SQL Server version:

N/A

Extended Events wait_type value:

The map_key value in sys.dm_xe_map_values is 218 in 2008 and 2008 R2, 225 in 2012, and 232 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:

The only time you should be concerned about this wait type is if you are using an AutoResetEvent in an unsafe assembly. For safe assemblies, this wait type can be 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 for an auto reset event

And other similar call stacks.

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

  1. SOS_Task::PostWait+90
    EventInternal<SuspendQueueSLock>::Wait+25c
    HostWait<EventAutoInternal<SuspendQueueSLock> >+18b
    CHostEvent<IHostAutoEvent,EventAutoInternal<SuspendQueueSLock>,4194529,DD_NullHelper>::Wait+4d
    CHostEventWrapper<IHostAutoEvent,EventAutoInternal<SuspendQueueSLock>,4194529,DD_NullHelper>::Wait+b0
    TranslateSecurityAttributes+39bc3
    StrongNameTokenFromAssemblyEx+f304f
    GetPrivateContextsPerfCounters+c80
    CallProtectorImpl::CallExternalTrustedFull<ClrEntryPointCallTraits,unsigned long,FunctionCallBinder_1<unsigned long,unsigned long (__cdecl*)(void * __ptr64),void * __ptr64> >+78
    CHostTask::TaskExecute+72
    CHostTask::TaskProcWrapper+9
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+a8
    SOS_Scheduler::ProcessTasks+299
    SchedulerManager::WorkerEntryPoint+261
    SystemThread::RunWorker+8f
    SystemThreadDispatcher::ProcessWorker+3c8
    SchedulerManager::ThreadEntryPoint+236
    BaseThreadInitThunk+d
    RtlUserThreadStart+21