| From: | Josh Berkus <josh(at)agliodbs(dot)com> |
|---|---|
| To: | "Medora Schauer" <mschauer(at)fairfield(dot)com>, "postgresql" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: slow select |
| Date: | 2003-10-22 16:23:15 |
| Message-ID: | 200310220923.15932.josh@agliodbs.com |
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| Lists: | pgsql-performance |
Medora,
> I'm using pg 7.3.4 to do a select involving a join on 2 tables.
> The query is taking 15 secs which seems extreme to me considering
> the indices that exist on the two tables. EXPLAIN ANALYZE shows
> that the indices aren't being used. I've done VACUUM ANALYZE on the
> db with no change in results. Shouldn't the indices be used?
No. You're selecting 100,000 records. For such a large record dump, a seq
scan is usually faster.
If you don't believe me, try setting enable_seqscan=false and see how long the
query takes.
--
Josh Berkus
Aglio Database Solutions
San Francisco
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