Having bad performance issues

Bill Moran wmoran at potentialtech.com
Wed Jul 25 19:13:38 UTC 2007

In response to "Pat Maddox" <pergesu at gmail.com>:

> I'm having some bad perf issues on a 6.2 server running PostgreSQL
> 8.2.4. I really don't know too much about this stuff...but it doesn't
> seem to be related to memory or CPU as they're barely being touched.
> Which leaves IO. Here's some vmstat output. My only guess is that the
> numbers under the faults section are pretty high. But I don't really
> know what that means. I'd appreciate any help.
> Here's the formatted vmstat output:  http://pastie.caboo.se/82165

You might get better results asking this on the PostgreSQL performance
mailing lists, unless you can determine that it's definitely a FreeBSD

If you feel strongly that the problem is FreeBSD-related, I'd suggest
you provide hardware details, such the type of disks and the controller.

If you feel strongly that the problem is with PostgreSQL, I would
post to the performance list at postgresql.org and include your disk
types, RAM sizes and your postgresql.conf

Taking a guess, based on your symptoms, I would expect you don't have
PostgreSQL tuned effectively.  If there's a lot of IO, but memory
isn't being used, then the memory is being wasted.  Start with
shared_buffers, and see if bumping that up helps (start with 1/3
of available RAM).

Bill Moran

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