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Description:
This wait type is when a thread that is reading from the transaction log is waiting for a log block to be supplied to it.
(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:
Maps to the DIRECTLOGCONSUMER_GETNEXT map_value in sys.dm_xe_map_values.
The map_key value in sys.dm_xe_map_values is 1106 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):
- Consuming the log (in this case, for checkpoint of a Hekaton table)
And other similar call stacks.
Abbreviated call stacks (list number matches known occurrences list):
- SOS_Task::PostWait+0x6f
EventInternal<SuspendQueueSLock>::Wait+0x1f4
DirectLogConsumer::GetNextLogBlock+0x5f7
HkHostCheckpointController::DoWork+0x264
HkHostControllerCtxtImpl::WorkLoop+0x1f7
SOS_Task::Param::Execute+0x231
SOS_Scheduler::RunTask+0xaa