SQL Server 2008 R2 wait types - "PREEMPTIVE_OS%"

Question

Where can I find documentation on wait types (SQL Server 2008 R2):

Select * from sys.dm_os_wait_stats where wait_type like 'PREEMPTIVE_OS%' 

For example, "PREEMPTIVE_OS_CRYPTIMPORTKEY". there is no such type of wait documented in msdn .

Answer 1

SQL Server typically runs threads in collaborative multitasking. When he turns to the OS, he must switch to proactive multitasking. Thus, waiting for PREEMPTIVE_OS% means that SQL Server expects the OS to do something.

You can find the documentation for the wait by removing the PREEMPTIVE_OS_ part. For example, the documentation for CryptImportKey can be found here .