Re: slow select - Mailing list pgsql-performance

From Josh Berkus
Subject Re: slow select
Date
Msg-id 200310220923.15932.josh@agliodbs.com
Whole thread Raw
In response to slow select  ("Medora Schauer" <mschauer@fairfield.com>)
List 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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