From: | Shaun Thomas <sthomas(at)townnews(dot)com> |
---|---|
To: | Varun Kacholia <varunk(at)cse(dot)iitb(dot)ac(dot)in> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Highly obscure and erratic |
Date: | 2002-06-19 14:35:57 |
Message-ID: | Pine.LNX.4.44.0206190931560.16252-100000@hamster.lee.net |
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Thread: | |
Lists: | pgsql-general |
On Wed, 19 Jun 2002, Varun Kacholia wrote:
> 1. SELECT * FROM dbmedia WHERE ID IN ((SELECT id FROM wdmedia WHERE
> word = 'whatever') ) LIMIT 20;
You probably didn't know this, but postgres is notorious for being
*very* bad at optimizing IN queries. Try this instead:
SELECT * FROM dbmedia d WHERE EXISTS
(SELECT 1 FROM wdmedia w WHERE w.id = d.id AND word = 'whatever')
LIMIT 20;
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