Re: Configuring PostgreSQL to minimize impact of checkpoints

From: "Matthew Nuzum" <cobalt(at)bearfruit(dot)org>
To: "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "'Jack Orenstein'" <jao(at)geophile(dot)com>
Cc: "'Jan Wieck'" <JanWieck(at)Yahoo(dot)com>, <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Configuring PostgreSQL to minimize impact of checkpoints
Date: 2004-05-11 13:35:18
Message-ID: 200405111335.i4BDZLDJ010593@ms-smtp-01.tampabay.rr.com
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>
> Jack Orenstein <jao(at)geophile(dot)com> writes:
> > I'm looking at one case in which two successive transactions, each
> > updating a handful of records, take 26 and 18 *seconds* (not msec) to
> > complete. These transactions normally complete in under 30 msec.
...
> None of this is necessarily going to fix matters for an installation
> that has no spare I/O capacity, though. And from the numbers you're
> quoting I fear you may be in that category. "Buy faster disks" may
> be the only answer ...
>

I had a computer once that had an out-of-the-box hard drive configuration
that provided horrible disk performance. I found a tutorial at O'Reilly
that explained how to use hdparm to dramatically speed up disk performance
on Linux. I've noticed on other computers I've set up recently that hdparm
seems to be used by default out of the box to give good performance.

Maybe your computer is using all of it's I/O capacity because it's using PIO
mode or some other non-optimal method of accessing the disk.

Just a suggestion, I hope it helps,

Matthew Nuzum | ISPs: Make $200 - $5,000 per referral by
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