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Description:
This wait type is when a thread is performing operations as part of a query using the sys.fn_xe_file_target_read_file table-value function to read event data from a file target. Note that this is a preemptive wait so the thread remains on the processor until the operation has completed.
(Books Online description: N/A)
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Added in SQL Server version:
2016
Removed in SQL Server version:
N/A
Extended Events wait_type value:
The map_key value in sys.dm_xe_map_values is 1094 in 2016 RTM. After 2016 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):
- Waiting for event data from the sys.fn_xe_file_target_read_file table-value function during a query
And other similar call stacks for operations with that TVF.
Abbreviated call stacks (list number matches known occurrences list):
- SOS_Task::PopWait+0xb4
XE_FileTargetTVF::InternalGetRow+0x26a
CQScanTVFStreamNew::GetRow+0xd6
CQScanSortNew::BuildSortTable+0x266
CQScanSortNew::OpenHelper+0xbc
CQScanNLJoinNew::Open+0x27
CQScanNLJoinNew::Open+0x27
CQueryScan::StartupQuery+0x2a7
CXStmtQuery::SetupQueryScanAndExpression+0x33e
CXStmtQuery::InitForExecute+0x34
CXStmtQuery::ErsqExecuteQuery+0x4df
CXStmtSelect::XretExecute+0x322
CMsqlExecContext::ExecuteStmts<1,1>+0x40d
CMsqlExecContext::FExecute+0xa9e
CSQLSource::Execute+0x981
process_request+0xe61
process_commands_internal+0x2df
process_messages+0x253
SOS_Task::Param::Execute+0x231
SOS_Scheduler::RunTask+0xaa