From: Peter Brawley
Date: July 7 2012 5:01pm
Subject: Re: Subquery taking too much time on 5.5.18?
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On 2012-07-07 9:52 AM, Cabbar Duzayak wrote:
> Hmm,
>
> Looking at the link http://www.artfulsoftware.com/infotree/queries.php
> and explanations here, EXISTS() should have performed better, but does
> not seem to??? I stopped it after about 5 minutes.
>
> I tried both:
>
>    SELECT * FROM A WHERE EXISTS (SELECT * FROM B WHERE A.id=B.A_ID and
> B.name like 'X%');
>
> and
>
>    SELECT * FROM A WHERE EXISTS (SELECT B.A_ID FROM B WHERE A.id=B.A_ID
> and B.name like 'X%');
>
> Both are slow...

What's the optimizer_switch setting?

PB