Re: postgres 7.4 at 100% - Mailing list pgsql-performance

From Chris Cheston
Subject Re: postgres 7.4 at 100%
Date
Msg-id e071108e0406290100338c171d@mail.gmail.com
Whole thread Raw
In response to Re: postgres 7.4 at 100%  (Josh Berkus <josh@agliodbs.com>)
Responses Re: postgres 7.4 at 100%  (Christopher Kings-Lynne <chriskl@familyhealth.com.au>)
Re: postgres 7.4 at 100%  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
Wow, this simple query is taking 676.24 ms to execute! it only takes
18 ms on our other machine.

This table has 150,000 rows. Is this normal?

no, the machine is not running software RAID.  Anyone have any ideas
next as to what I should do to debug this? I'm really wondering if the
Linux OS running SMP is the cause.

Thanks,
Chris

live=# explain analyze SELECT id FROM calllogs WHERE from = 'you';
                                                QUERY PLAN
----------------------------------------------------------------------------------------------------------
 Seq Scan on calllogs  (cost=0.00..136.11 rows=24 width=4) (actual
time=0.30..574.72 rows=143485 loops=1)
   Filter: (from = 'you'::character varying)
 Total runtime: 676.24 msec
(3 rows)

explain analyze for inserts is fast too.


On Mon, 28 Jun 2004 09:47:59 -0700, Josh Berkus <josh@agliodbs.com> wrote:
>
> Tom,
>
> > So while he surely should not go back to 40, it seems there's another
> > factor involved here that we've not recognized yet.
>
> I'd agree.  Actually, the first thing I'd do, were it my machine, is reboot it
> and run memtest86 overnight.    CPU thrashing like that may indicate bad RAM.
>
> If the RAM checks out, I'd like to see the EXPLAIN ANALYZE for some of the
> longest-running queries, and for those INSERTS.
>
> Also, is the new machine running Software RAID?
>
> --
> Josh Berkus
> Aglio Database Solutions
> San Francisco
>
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