There are many wait types in SQL Server and not all of them are documented. Long ago I wrote blog on PREEMPTIVE and Non-PREEMPTIVE waits. SQL SERVER – PREEMPTIVE and Non-PREEMPTIVE – Wait Type – Day 19 of 28. In this blog post we will take a look at how to solve wait PREEMPTIVE_OLEDB_RELEASE.
Once I was contacted when there was wait of PREEMPTIVE_OLEDB_RELEASE seen in SQL Server. Here are the few columns from sys.dm_exec_requests.
There was no documentation available for this wait type. From the name, it looks like some kind of cleanup (release) task. Here was the behavior which I saw.
- All above were in RUNNING state.
- ONLY wait duration and elapsed time column values were increasing.
- There was a network outage earlier, which caused few SPID to run continuously so they were killed and now sitting in KILLED/ROLLBACK state. They were running UPDATE statements earlier.
As on the internet, there was no other help on this subject and there is no further documentation available from Microsoft as well. The customer was really keen on removing this wait stats. The good thing for us that their maintenance window was coming up on the very same day.
I explained to my client that they should restart the SQL instance to remove those sessions. And as expected, restarted to clear those SPIDs.
Reference: Pinal Dave (http://blog.SQLAuthority.com)