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CHECKPOINT_QUEUE

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Description:

This wait type is when the background checkpoint process is idle waiting to be signaled that a new checkpoint request has been entered into the checkpoint queue.

(Books Online description: “Occurs while the checkpoint task is waiting for the next checkpoint request.”)

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Added in SQL Server version:

2008

Removed in SQL Server version:

N/A

Extended Events wait_type value:

The map_key value in sys.dm_xe_map_values is 129 in 2008 and 2008 R2, and 133 in 2012 and 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. Wait times will vary for this wait type as it depends on how long it takes for new checkpoint requests to happen. Note that manual CHECKPOINT operations do not incur this wait type as they do not go through the checkpoint queue.

This wait type is one that I usually filter out as a benign wait when doing wait statistics analysis.

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

  1. Waiting for a new checkpoint request

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

  1. SOS_Task::PostWait+9e
    EventInternal<SuspendQueueSLock>::Wait+2ca
    ResQueueBase::Dequeue+1cf
    CheckpointHelper+ca
    CheckpointLoopWorker+da
    RegisterCheckPtWorker+133
    CheckpointLoop+d3
    CheckpointThread+55
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+ab