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Re: PERFORMANCE meeting summary & next meeting topic!

From: "Roth, Gabrielle" <gabrielle(dot)roth(at)xo(dot)com>
To: <pdxpug(at)postgresql(dot)org>
Subject: Re: PERFORMANCE meeting summary & next meeting topic!
Date: 2006-09-20 21:40:00
Message-ID: E2383CA82A645A45B72D523F5A29311A032BC89C@UTSANDMAIL02.mail.inthosts.net (view raw or flat)
Thread:
Lists: pdxpug
Mr Wheeler wrote:

> Actually, I think that the consensus was that she should try  
> increasing the sort_mem on the 7.4 database to see if that 
> helps. But upgrading is a no-brainer, too. :-)

Based on my tests today, upgrading is going to be the solution for sure.
On 8.1, the runtime for the problem query is ~5msec.

In the meantime, while I wait to schedule the prod upgrade *cough*, I
tried two things:
1. VACUUM ANALYZE.  Duh.  This should have been the first thing I
checked.  (Forgot to put this test db in the maintenance queue. :$
*slaps self*) This improved things significantly (~2800 msec runtime as
calculated by the planner down to ~50msec.  Yay.)  This would be why my
indexes weren't being used.

2.  I tried doubling sort_mem on my production machine to 2048K.  It
made a noticable difference (we're down to ~40msec now, yee-haw).  This
had no [visible] detrimental effect on the machine, and since I only
have 14 users & most of my queries are pretty straightforward, I figured
I could keep pushing it.  However, further increases of sort_mem didn't
make any difference (I tried up to 16384), so I left it at 2048.

> Thanks for a fun meeting, all!
\e! \e!  I used it today!

- gabrielle -
"5 out of 4 people have a problem with math."

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Next:From: David E. WheelerDate: 2006-09-20 22:04:31
Subject: Re: PERFORMANCE meeting summary & next meeting topic!
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Subject: Re: PERFORMANCE meeting summary & next meeting topic!

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