(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_WINSOCKOPS

(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 Winsock (Windows sockets).

(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 490 in 2008 and 2008 R2, 538 in 2012, and 554 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. Setting the hostname for a connection during database mirroring
  2. Setting the hostname for a connection during database mirroring

And other similar call stacks.

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

  1. SOS_Task::PopWait+b1
    AutoSwitchPreemptive::~AutoSwitchPreemptive+95
    DbmGlobalStateMgr::SetHostName+209
    DbmServer::GetServerConnectString+6e
    LSConfigureRequest::Init+5c
    LSConfigureRequestV2::Init+52
    LsConnectionStateMachine::SendConfigureRequest+cb
    LsConnectionStateMachine::StartingAction+d0
    LsStateMachineBase::PostEvent+1d7
    LsStateMgr::ProcessEvents+113
    DbmDatabaseStateMgr::MasterThreadRoutine+303
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+ab
  2. SOS_Task::PopWait+b1
    AutoSwitchPreemptive::~AutoSwitchPreemptive+95
    DbmGlobalStateMgr::SetHostName+209
    DbmGlobalStateMgr::Init+94
    DbmServer::Init+1b0
    DBMirroring::UpdateEndpoint+1f
    IBrokerEndpointConfig::PostTransactionCommitNotify_Change+ff
    VLR_RegisterEndpoint::CommitAndRelease+7b
    XdesRMReadWrite::CommitAllVirtualLogRecs+e4
    XdesRMReadWrite::PreDestruct+23e
    XdesRMFull::~XdesRMFull+b2
    XdesRMFull::`vector deleting destructor’+14
    XactRM::SinglePhaseCommit+1e3
    XactRM::CommitInternal+472
    FullXactImp::Commit+33f
    CMsqlXactInternalReadWrite::Commit+19
    CMsqlXactImp::Commit+1d6
    CXStmtDDL::FinishNormalImp+e1
    CMsqlExecContext::ExecuteStmts<0,1>+9d8
    CMsqlExecContext::FExecute+a58
    CSQLSource::Execute+86c
    process_request+a57