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PARALLEL_REDO_WORKER_WAIT_WORK

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Description:

This wait type is when one of the parallel threads performing redo for a database is waiting for some work to do.

(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 1135 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. Although this wait type can be high on some systems, that just means there is a lot of time when there’s nothing for the redo threads to do.

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

  1. Waiting for some work to be queued for redo

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

  1. SOS_Task::PostWait+0x6f
    EventInternal<SuspendQueueSLock>::Wait+0x1f4
    ParallelRedoWorker::RedoWorkerLoop+0x38d
    ParallelRedoWorker::RedoWorkerEntryPoint+0xa2
    SOS_Task::Param::Execute+0x231
    SOS_Scheduler::RunTask+0xaa