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From: "Adam Rich" <adam.r@sbcglobal.net>
To: "'Craig A. James'" <cjames@modgraph-usa.com>,
	"'Guy Rouillier'" <guyr-ml1@burntmail.com>,
	"'PostgreSQL Performance'" <pgsql-performance@postgresql.org>
Subject: Re: High update activity, PostgreSQL vs BigDBMS
Date: Sun, 7 Jan 2007 20:26:29 -0600
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Importance: Normal


I'm using 8.2 and using order by & limit is still faster than MAX()
even though MAX() now seems to rewrite to an almost identical plan
internally.

Count(*) still seems to use a full table scan rather than an index scan.

Using one of our tables, MySQL/Oracle/MS-SQL all return instantly while
PG takes longer ther 700ms.  Luckily we can design around this issue.


-----Original Message-----
From: pgsql-performance-owner@postgresql.org
[mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Craig A.
James
Sent: Sunday, January 07, 2007 5:57 PM
To: Guy Rouillier; PostgreSQL Performance
Subject: Re: [PERFORM] High update activity, PostgreSQL vs BigDBMS


Craig A. James wrote:
> The "idiom" to replace count() was 
> "select col from tbl order by col desc limit 1".  It worked miracles
for 
> my app.

Sorry, I meant to write, "the idiom to replace MAX()", not count()...
MAX() was the function that was killing me, 'tho count() also gave me
problems.

Craig

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