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Re: Long execution time despite LIMIT 3
Posted by: Joachim Berger ()
Date: June 21, 2011 02:06AM

It somehow seems I might be getting there:


I could rewrite the SELECT as follows:

(SELECT m.*, m.flags + 0 flags
FROM messages_test m
WHERE (m.thread = 817549.001266066) AND (id_user_s = 817549) AND (del_s = 0))

UNION

(SELECT m.*, m.flags + 0 flags
FROM messages_test m
WHERE (m.thread = 817549.001266066) AND (id_user_r = 817549) AND (del_r = 0))

order by id desc
LIMIT 3;


and have indexes like:
test1 (thread,id_user_r,del_r)
test2 (thread,id_user_s,del_s)


What do you think?

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Subject Views Written By Posted
Long execution time despite LIMIT 3 1321 Joachim Berger 06/19/2011 12:47PM
Re: Long execution time despite LIMIT 3 533 Joachim Berger 06/19/2011 12:54PM
Re: Long execution time despite LIMIT 3 525 Rick James 06/20/2011 06:33PM
Re: Long execution time despite LIMIT 3 509 Joachim Berger 06/20/2011 11:44PM
Re: Long execution time despite LIMIT 3 558 Joachim Berger 06/21/2011 02:06AM
Re: Long execution time despite LIMIT 3 559 Rick James 06/21/2011 07:23AM
Re: Long execution time despite LIMIT 3 476 Joachim Berger 06/21/2011 07:28AM
Re: Long execution time despite LIMIT 3 551 Joachim Berger 06/21/2011 10:33AM
Re: Long execution time despite LIMIT 3 616 Rick James 06/21/2011 10:08PM
Re: Long execution time despite LIMIT 3 730 Joachim Berger 06/22/2011 12:33AM
Re: Long execution time despite LIMIT 3 542 Rick James 06/22/2011 07:26PM
Re: Long execution time despite LIMIT 3 519 Joachim Berger 06/22/2011 11:45PM
Re: Long execution time despite LIMIT 3 477 Rick James 06/23/2011 08:53AM
Re: Long execution time despite LIMIT 3 593 Joachim Berger 06/24/2011 02:51AM


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