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LOGPOOL_CONSUMERSET

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Description:

This wait type is when a thread is waiting for an operation to do with the log pool. This is an in-memory cache of recently flushed log blocks, to help avoid log readers having to do physical reads of the log file (e.g. for sending log blocks to asynchronous availability group replicas).

(Books Online description: N/A)

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Added in SQL Server version:

2012

Removed in SQL Server version:

N/A

Extended Events wait_type value:

The map_key value in sys.dm_xe_map_values is 772 in 2012 and 790 in 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.

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

  1. Initializing a log pool consumer (in this case, while utilizing the log pool when rolling back a transaction)
  2. Destroying a log pool consumer (in this case, while utilizing the log pool when rolling back a transaction)

And other similar call stacks.

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

  1. SOS_Task::PostWait+9e
    EventInternal<SuspendQueueSLock>::Wait+2ca
    SOS_RWLock::GetLongWait+10b
    LogPoolMgr::WaitOnConsumerSet+1d2
    LogConsumer::Init+2c8
    SQLServerLogIter::Init+9b
    XdesRMFull::Rollback+3ef
    XactRM::RollbackInternal+346
    CMsqlXactInternalBase::RollbackInternal+c1
    CMsqlXactInternalReadWrite::Rollback+e
    CMsqlXactImp::RollbackInternal+b6
    CMsqlXactImp::Rollback+6a
    CXStmtDML::FinishNormalImp+cd
    CXStmtDML::FinishOnExceptionImp+423
  2. SOS_Task::PostWait+9e
    EventInternal<SuspendQueueSLock>::Wait+2ca
    SOS_RWLock::GetLongWait+10b
    LogPoolMgr::WaitOnConsumerSet+1d2
    LogPoolMgr::UnRegisterLogConsumer+1a
    LogConsumer::Close+4ea
    SQLServerLogIter::Close+4b
    XdesRMFull::RollbackNested+2a5
    XactRM::RollbackNestedXact+ff
    FullXactImpBase::RollbackNestedXact+53
    CMsqlXactInternalReadWrite::RollbackNestedXact+5d
    CMsqlXactImp::RollbackNestedXact+19
    CAutoMsqlXact::RollbackNestedXact+5b
    CXStmtDML::RollbackNestedXact+1b
    CXStmtDML::FinishOnExceptionImp+1a7