(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_AUTHENTICATIONOPS

(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 authentication.

(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 365 in 2008 and 2008 R2, 412 in 2012, and 428 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:

If you see long waits for this wait type, have your infrastructure team investigate performance issues with servers that provide security authentication and authorization, such as Active Directory Controllers and Domain Controllers.

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. Getting authentication information (in this case, while setting up SSL for a new communication link)
  2. Getting authentication information (in this case, while processing a login from a client)
  3. Getting authentication information (in this case, while setting up the TDS protocol)

And other similar stacks.

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

  1. SOS_Task::PopWait+b1
    SOS_ExternalAutoWait::~SOS_ExternalAutoWait+7c
    Ssl::Handshake+864
    CryptoBase::ProcessAndWriteSecurityToken+11a
    CryptoBase::ProcessAddProvider+163
    SNIProcessAddProviderOnWorker+39
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+ab
  2. SOS_Task::PopWait+b1
    SOS_ExternalAutoWait::~SOS_ExternalAutoWait+7c
    SNISecImpersonateContext+3bf
    intnl_impersonate_client+289
    FInterrogateLogin+1f3
    FindLogin+23b
    login+829
    process_login_finish+16e
    process_commands+456
    TDSSNIClient::AddSSPIProviderHandler+474
    TDSSNIClient::AddProviderHandler+38
    SNIProcessAddProviderOnWorker+122
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+ab
  3. SOS_Task::PopWait+b1
    SOS_ExternalAutoWait::~SOS_ExternalAutoWait+7c
    SNISecInitPackageEx+648
    InitializeTDS+47e
    FRunCommunicationsManager+4e
    CommunicationsManager+3c6
    SOS_Task::Param::Execute+21e
    SOS_Scheduler::RunTask+ab