Re: [PERFORM] a heavy duty operation on an "unused" table kills my server

2010-01-17 Thread Eduardo Piombino
> Seems like you'd also need to think about priority inversion, if the > "low-priority" backend is holding any locks. > I'm not sure that priority inversion would be right in this scenario, because in that case the IO storm would still be able to exist, in the cases where the slow jobs collide wit

Re: [PERFORM] a heavy duty operation on an "unused" table kills my server

2010-01-17 Thread Greg Smith
Eduardo Piombino wrote: In the case where priority inversion is not to be used, I would however still greatly benefit from the slow jobs/fast jobs mechanism, just being extra-careful that the slow jobs, obviously, did not acquire any locks that a fast job would ever require. This alone would b

Re: [PERFORM] a heavy duty operation on an "unused" table kills my server

2010-01-17 Thread Tom Lane
Greg Smith writes: > In this context, "priority inversion" is not a generic term related to > running things with lower priorities. It means something very > specific: that you're allowing low-priority jobs to acquire locks on > resources needed by high-priority ones, and therefore blocking t