From: | Matt Mello <alien(at)spaceship(dot)com> |
---|---|
To: | pgsql-performance <pgsql-performance(at)postgresql(dot)org> |
Subject: | ISNULL performance tweaks |
Date: | 2003-03-06 18:51:11 |
Message-ID: | 3E67989F.7030001@spaceship.com |
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Thread: | |
Lists: | pgsql-performance |
I have some existing code running in a production environment with
embedded SELECTs whose WHERE's use ISNULL tests on indexed foreign key
fields. This is obviously very slow.
My ISNULL *queries *take anywhere from 6 to 40 seconds. These queries
are used to generate reports to a device which times out at 20 seconds,
so half the time these devices don't get their reports, which makes my
customers VERY angry.
I recall seeing an email (I believe on this list) about how to improve
performance of ISNULL's with some sort of tweak or trick. However, I
can't find that email anywhere, and couldn't find it searching the
maillist archives.
So, until I have the time to code the fixes I need to prevent the use of
ISNULL, does anybody know how I can speed up this existing system?
Man, I wish PG indexed nulls! Is there any plan on adding these in the
future?
Thanks for any help you can give!
--
Matt Mello
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