SQLTRACE_FILE_READ_IO_COMPLETION

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Description:

This wait type is when a thread is waiting for a read from a trace file to complete.

(Books Online description: N/A)

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Added in SQL Server version:

2008 R2

Removed in SQL Server version:

N/A

Extended Events wait_type value:

The map_key value in sys.dm_xe_map_values is 601 in 2008 R2, 683 in 2012, and 701 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 I suppose these waits may become longer if there is I/O subsystem contention.

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

  1. Waiting for a read from a trace file to complete

And other similar call stacks.

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

  1. SOS_Task::PostWait+90
    EventInternal<SuspendQueueSLock>::Wait+1f9
    CTraceReadBuf::WaitForIoCompletion+bc
    CTraceFileReader::GetNextBlock+10e
    CRowsetTraceTable::OpenNextFile+128
    CRowsetTraceTable::GetRowImpl+2b0
    CRowsetTraceTable::GetRow+23
    CQScanTVFStreamNew::GetRow+d5
    CQScanFilterNew::GetRowHelper+20
    CQueryScan::GetRow+81
    CXStmtQuery::ErsqExecuteQuery+54a
    CXStmtSelect::XretExecute+2f7
    CMsqlExecContext::ExecuteStmts<1,1>+400
    CMsqlExecContext::FExecute+a33
    CSQLSource::Execute+866
    process_request+73c
    process_commands+51c
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+a8