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PREEMPTIVE_OS_REMOVEDIRECTORY

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Description:

This wait type is when a thread is calling the Windows RemoveDirectory function.

(Books Online description: N/A)

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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 461 in 2008 and 2008 R2, 509 in 2012, and 525 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:

This wait type is generally not an issue unless FILESTREAM’ data is being used. If there are a large amount of files in the FILESTREAM data container, dropping the database can take a long time (many seconds) and it will register this wait type for the duration.

Note that when a thread calls out to Windows, the thread changes from non-preemptive (SQL Server controls the thread) to preemptive (Windows controls the thread) mode. The thread’s state will be listed as RUNNING, as SQL Server doesn’t know what Windows is doing with the thread.

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

  1. Removing the FILESTREAM data container while dropping a database

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

  1. SOS_Task::PopWait+0xb1
    AutoSwitchPreemptive::~AutoSwitchPreemptive+0x95
    StreamFileMgr::RemoveContainer+0xdf
    StreamFileMgr::DoDeleteFsFile+0x50
    AsynchronousDiskAction::ExecuteDeferredAction+0xbf
    AsynchronousDiskWorker::ThreadRoutine+0x15c
    SubprocEntrypoint+0xa7f
    SOS_Task::Param::Execute+0x21e
    SOS_Scheduler::RunTask+0xab