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Re: very slow left join

From: Ben <bench(at)silentmedia(dot)com>
To: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: very slow left join
Date: 2008-05-16 18:43:12
Message-ID: Pine.LNX.4.64.0805161139080.3347@localhost.localdomain (view raw or flat)
Thread:
Lists: pgsql-performance
On Fri, 16 May 2008, Scott Marlowe wrote:

> Well, I'm guessing that you aren't in locale=C and that the text

Correct, I am not. And my understanding is that by moving to the C locale, 
I would loose utf8 validation, so I don't want to go there. Though, it's 
news to me that I would get any kind of select performance boost with 
locale=C. Why would it help?

> functions in your query aren't indexed.  Try creating an index on them
> something like:
>
> create index abc_txtfield_func on mytable (substring(textfield,1,5));
>
> etc and see if that helps.

It does not. :(

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Subject: Re: very slow left join
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