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Sql Server SPID -5

I had an interesting issue today when a colleague was running a long running IO intensive query. I ran sp_who2 to view the activity and saw that the query was running multi-threaded, but was blocked by a SPID of -5.

Yes, that’s SPID minus five, or negative five. (putting this here so that google searches maybe work?).

https://d33wubrfki0l68.cloudfront.net/6b5af40d6a8aec5993b430ee56541347b5dfc490/02af0/blog/sql-spid-5/2022-02-21_15-28-35.jpg
blocking SPID -5

Google not working

I tried to use Google to get information on this but it seems that Google doesn’t allow you to search for negative numbers. So searching for SPID -5 doesn’t show any decent information to understand what’s going on.

As a last resort, I posted to Twitter.

I got some great responses and will let you navigate to the tweet or click on the links below. Mostly importantly, the links below describe the following.

By itself, blocking_session_id -5 does not indicate a performance problem. -5 is an indication that the session is waiting on an asynchronous action to complete.

References

How can I search Google for a negative number?

Negative Blocking Session Ids (-5 = Latch ANY TASK RELEASOR)

sys.dm_exec_requests (Transact-SQL)