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Description:
This wait type seems to be a generic wait for background worker threads involved in in-memory table processing. Note that this is a preemptive wait, so the thread continues executing on the processor until the work is complete.
(Books Online description: “Internal use only.”)
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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 1065 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:
Anecdotal evidence suggests that this wait type may become a bottleneck when using the Telemetry Extended Events session.
Known occurrences in SQL Server (list number matches call stack list):
- An in-memory background worker thread ending a period of running in preemptive mode.
And other similar call stacks.
Abbreviated call stacks (list number matches known occurrences list):
- sqldk.dll!SOS_Task::PopWait+0x107
sqlmin.dll!SOS_ExternalAutoWait::~SOS_ExternalAutoWait+0x5f
sqlmin.dll!SOS_Task::AutoSwitchPreemptive::~AutoSwitchPreemptive+0x5c
sqlmin.dll!HkHostThreadWrapper+0x2fc
sqldk.dll!SOS_Task::Param::Execute+0x232
sqldk.dll!SOS_Scheduler::RunTask+0xb5