From: Craig A. James <cjames@modgraph-usa.com>
To: Steve Atkins <steve@blighty.com>
To: pgsql-performance@postgresql.org
Subject: Re: Performance of count(*)
Date: Thu, 22 Mar 2007 10:21:21 -0800
Message-ID: <4602C921.3070303@modgraph-usa.com> (raw)
In-Reply-To: <228F06CD-3642-4A42-813A-648285A3BDBC@blighty.com>
References: <Pine.LNX.4.62.0703221149210.13747@wr-linux02>
<200703221208.19358.albert@sedifa.com>
<Pine.LNX.4.64.0703221323590.1503@ismoli.solenovo.jns>
<20070322141807.GE11402@mathom.us>
<46029DE3.9030505@modgraph-usa.com>
<4602A15B.7000908@wildenhain.de>
<4602BB19.9050306@modgraph-usa.com>
<228F06CD-3642-4A42-813A-648285A3BDBC@blighty.com>
Steve Atkins wrote:
> As long as you're ordering by some row in the table then you can do that in
> straight SQL.
>
> select a, b, ts from foo where (stuff) and foo > X order by foo limit 10
>
> Then, record the last value of foo you read, and plug it in as X the next
> time around.
We've been over this before in this forum: It doesn't work as advertised. Look for postings by me regarding the fact that there is no way to tell the optimizer the cost of executing a function. There's one, for example, on Oct 18, 2006.
> I think the problem is more that most web developers aren't very good
> at using the database, and tend to fall back on simplistic, wrong,
> approaches
> to displaying the data. There's a lot of monkey-see, monkey-do in web
> UI design too, which doesn't help.
Thanks, I'm sure your thoughtful comments will help me solve my problem. Somehow. ;-)
Craig
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To: pgsql-performance@postgresql.org
Cc: cjames@modgraph-usa.com, steve@blighty.com
Subject: Re: Performance of count(*)
In-Reply-To: <4602C921.3070303@modgraph-usa.com>
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