From: | "Steinar H(dot) Gunderson" <sgunderson(at)bigfoot(dot)com> |
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To: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: Performance pb vs SQLServer. |
Date: | 2005-08-15 01:37:41 |
Message-ID: | 20050815013741.GA32106@uio.no |
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Thread: | |
Lists: | pgsql-performance |
On Sun, Aug 14, 2005 at 09:18:45PM -0400, Tom Lane wrote:
> Not really. There's been some speculation about implementing index
> "skip search" --- once you've verified there's at least one visible
> row of a given index value, tell the index to skip to the next different
> value instead of handing back any of the remaining entries of the
> current value. But it'd be a lot of work and AFAICS not useful for
> very many kinds of queries besides this.
This is probably a completely wrong way of handling it all, but could it be
done in a PL/PgSQL query like this? (Pseudo-code, sort of; I'm not very well
versed in the actual syntax, but I'd guess you get the idea.)
x = ( SELECT foo FROM table ORDER BY foo LIMIT 1 );
WHILE x IS NOT NULL
RETURN NEXT x;
x = ( SELECT foo FROM table WHERE foo > x ORDER BY foo LIMIT 1 );
END;
(Replace with max() and min() for 8.1, of course.)
/* Steinar */
- fond of horrible hacks :-)
--
Homepage: http://www.sesse.net/
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