Re: [PERFORM] Hanging queries on dual CPU windows

From: Jan de Visser <jdevisser(at)digitalfairway(dot)com>
To: "PostgreSQL-development" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [PERFORM] Hanging queries on dual CPU windows
Date: 2006-03-12 18:10:59
Message-ID: 200603121310.59861.jdevisser@digitalfairway.com
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On Sunday 12 March 2006 09:40, Magnus Hagander wrote:
> > > If so,
> > > we could perhaps recode that part using a Mutex instead of
> >
> > a critical
> >
> > > section - since it's not a performance critical path, the
> >
> > difference
> >
> > > shouldn't be large. If I code up a patch for that, can you re-apply
> > > SP1 and test it? Or is this a production system you can't
> >
> > really touch?
> >
> > I can do whatever the hell I want with it, so if you could
> > cook up a patch that would be great.
> >
> > As a BTW: I reinstalled SP1 and turned stats collection off.
> > That also seems to work, but is not really a solution since
> > we want to use autovacuuming.
>
> Ok, I've coded up a patch that changes the code to use a mutex instead.
> Patch attached. You can get a precompiled postgres.exe at
> http://www.hagander.net/download/postgres.exe_mutex.zip. You need to
> copy this file to postmaster.exe as well - they are supposed to be
> identical. It's based off a snapshot of 8.1-stable.
>
> Looking a my system while testing this it still loooked like it was
> hanging on that plac ein the code, even though I saw no problems. So I'm
> not convinced we can actually trust the stacktrace from the non-default
> threads. So I don't think this patch will actually work :-( But it's
> worth a try.
>
> (Oh, and I moved the thread over to -hackers, seems more correct at this
> time)

Thanks Magnus,

I'll try tomorrow. Will let you know ASAP (8:30 EST I guess :).

If this doesn't work, how do we progress?

>
> //Magnus

jan

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Jan de Visser                     jdevisser(at)digitalfairway(dot)com

                Baruk Khazad! Khazad ai-menu!
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