Re: very slow left join - Mailing list pgsql-performance

From Ben
Subject Re: very slow left join
Date
Msg-id Pine.LNX.4.64.0805161139080.3347@localhost.localdomain
Whole thread Raw
In response to Re: very slow left join  ("Scott Marlowe" <scott.marlowe@gmail.com>)
Responses Re: very slow left join
List 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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