Re: Deathly slow performance on SMP red-hat system

["Joshua D. Drake" <jd(at)commandprompt(dot)com>]

Patrick TJ McPhee wrote:
> I have a Red Hat ELsmp system running on a dual opteron hp server with
> 16 gigs of memory. I believe the RH installation is straight out of the
> box. I've compiled postgres 8.1.4 from sources.
>
> The problem is that query performance is horrible, and I can't think
> why, although it seems clear the problem is outside the query engine.
> For instance, "select 1" takes on the order of 100ms. Explain analyze
> doesn't shed much light on why this might be:
>
>  explain analyze select 1;
>                                      QUERY PLAN                                     
> ------------------------------------------------------------------------------------
>  Result  (cost=0.00..0.01 rows=1 width=0) (actual time=0.005..0.006 rows=1 loops=1)
>  Total runtime: 0.059 ms
> (2 rows)
>
> But if I turn on duration logging, I get timings like
>  LOG:  duration: 91.480 ms
>
> I was able to pg_reload 80 gigs of data in a reasonable amount of time, but
> individual queries are taking a long time.
>
> I'm wondering if anyone's seen anything like this.

Vacuum? Analyze?

Joshua D. Drake

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