| From: | Jeff Frost <jeff(at)frostconsultingllc(dot)com> |
|---|---|
| To: | Glenn Sullivan <glenn(dot)sullivan(at)varianinc(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: SELECT performance problem |
| Date: | 2007-02-20 23:41:37 |
| Message-ID: | Pine.LNX.4.64.0702201540040.3892@discord.home.frostconsultingllc.com |
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| Lists: | pgsql-performance |
On Tue, 20 Feb 2007, Glenn Sullivan wrote:
> I am updating from 7.4.5 to 8.2.3. I have noticed a significant
> slowdown in simple searches such as
> "select filename from vnmr_data where seqfil = 'sems';"
> This returns 12 rows out of 1 million items in the table.
> On 7.4.5, this takes about 1.5 seconds. On 8.2.3, it is taking
> about 9 seconds.
>
> I have played with different values of:
> work_mem, temp_buffers, shared_buffers and effective_cache_size
> and none of them make any difference.
>
> I am running on redhat Linux 4 64bit.
Glenn,
Can you forward us the explain analyze output from 7.4.5 and 8.2.3 for the
query in question?
Also, is the hardware the same between 7.4.5 and 8.2.3? If not, what is the
difference?
--
Jeff Frost, Owner <jeff(at)frostconsultingllc(dot)com>
Frost Consulting, LLC http://www.frostconsultingllc.com/
Phone: 650-780-7908 FAX: 650-649-1954
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