(Republishing, or using this info in a commercial product/website, is prohibited without permission. All other uses are permitted. If in doubt, please ask.)

PREEMPTIVE_OS_SECURITYOPS

(Back to main page…)

Description:

This wait type is a generic wait for when a thread is calling one of several Windows functions related to security.

(Books Online description: N/A)

Questions/comments on this wait type? Click here to send Paul an email, especially if you have any information to add to this topic.

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 487 in 2008 and 2008 R2, 535 in 2012, and 551 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.

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. Impersonating a login as part of running a distributed query
  2. Impersonating a login as part of running a distributed query
  3. Impersonating a login as part of running a distributed query

And other similar call stacks.

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

  1. SOS_Task::PopWait+bc
    SOS_Task::AutoSwitchPreemptive::~AutoSwitchPreemptive+72
    CSECAutoImpersonateForDQ::Impersonate+226
    COledbConnect::GetSession+1fc
    COledbRangeSchema::GetRowset+cb
    COledbRangeSchema::GetRowset+2e4
    CQScanRmtScanNew::OpenConnection+1c4
    CQScanRmtBaseNew::OpenHelper+76
    CQScanSortNew::BuildSortTable+56
    CQScanSortNew::OpenHelper+cc
    CQScanSortNew::Open+10
    CQueryScan::StartupQuery+1e0
    CXStmtQuery::SetupQueryScanAndExpression+19f
    CXStmtQuery::InitForExecute+1f
    CXStmtQuery::ErsqExecuteQuery+2fb
    CXStmtSelect::XretExecute+28a
    CMsqlExecContext::ExecuteStmts<1,1>+352
    CMsqlExecContext::FExecute+878
    CSQLSource::Execute+7d3
  2. SOS_Task::PopWait+bc
    SOS_Task::AutoSwitchPreemptive::~AutoSwitchPreemptive+72
    CSECAutoImpersonateForDQ::Impersonate+226
    COledbConnect::GetSession+1fc
    SpTestLinkedServer+241
    CSpecProc::ExecuteSpecial+25b
    CXProc::Execute+14e
  3. SOS_Task::PopWait+bc
    AutoSwitchPreemptive::~AutoSwitchPreemptive+9a
    CSECAutoImpersonateForDQ::Impersonate+271
    CQScanRmtQueryNew::CreateQueryRowset+68
    CQScanRmtQueryNew::Open+84
    CQueryScan::StartupQuery+1e0
    CXStmtQuery::SetupQueryScanAndExpression+19f
    CXStmtQuery::InitForExecute+1f
    CXStmtQuery::ErsqExecuteQuery+2fb
    CXStmtSelect::XretExecute+28a
    CMsqlExecContext::ExecuteStmts<1,1>+352
    CMsqlExecContext::FExecute+878
    CSQLSource::Execute+7d3