Re: High SYS CPU - need advise

ok, I've applied that patch and ran. The stall started around 13:50:45...50
and lasted until the end

https://dl.dropbox.com/u/109778/postgresql-2012-11-16_134904-stripped.log

the actual log has more data (including statement following each 'spin
delay' record), but there is some sensitive info inside which I can't share
with public.

-- Vlad

yup. this problem doesn't smell like lwlock issues. typically there
> the problem manifests as low cpu performance, everybody waits.
> classic spinlock contention (at least from what i've seen) is very
> high *userspace* cpu utilization and low work output. this time it's
> different -- OP is bogging in the kernel so it's not impossible we're
> troubleshooting the symptom, not the cause.
>
> > In 9.3 there is a new field that tells how many spin delays there were
> > on the mutex that is behind each lock. That was commit
> > b79ab00144e64217d41, maybe he can port that back to his version.
> >
> > But that only tells you about LWLock mutexes, not about all the other
> > ones in PG.
> >
> > The attached patch logs every spin delay with where in the source it
> comes from.
>
> yeah, OP should fire this off. good stuff. I'll bet lunch (if we ever
> happen to meet) it's on buffer pin.
>
> merlin
>