From: Rod Taylor <pg@rbt.ca>
To: Dawid Kuroczko <qnex42@gmail.com>
Cc: Steve Wampler <swampler@noao.edu>
Cc: pgsql-sql@postgresql.org, Bruno Wolff III <bruno@wolff.to>
Subject: Re: Make COUNT(*) Faster?
Date: Fri, 08 Jul 2005 11:38:31 -0400
Message-ID: <1120837111.24708.252.camel@home> (raw)
In-Reply-To: <758d5e7f050708083423c20c70@mail.gmail.com>
References: <9EF2931D-1097-470D-8ECB-59D00166C96F@apple.com>
<60vf3mklue.fsf@dba2.int.libertyrms.com>
<42CE89CA.2070607@noao.edu>
<20050708143508.GD22725@wolff.to>
<42CE96AF.3020903@noao.edu>
<1120836150.24708.251.camel@home>
<758d5e7f050708083423c20c70@mail.gmail.com>
On Fri, 2005-07-08 at 17:34 +0200, Dawid Kuroczko wrote:
> On 7/8/05, Rod Taylor <pg@rbt.ca> wrote:
> > Create 2 sequences, one for counting tuple additions and one for
> > counting tuple deletions.
> >
> > When you INSERT a tuple, bump the "added" sequence (select nextval());
> >
> > When you DELETE a tuple, bump the "deleted" sequence (select nextval());
> >
> > To retrieve an approximate count, take the current value of both
> > sequences (select directly -- don't use currval) and subtract the
> > "deletes" from the "adds".
>
> Never thought of that! Good idea. :-)
>
> Regards,
> Dawid
>
> PS: There aren't any on ROLLBACK triggers, right? ;-)))
No. You could make then RI triggers and have them deferred until commit
though.
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To: pgsql-sql@postgresql.org
Cc: pg@rbt.ca, qnex42@gmail.com, swampler@noao.edu, bruno@wolff.to
Subject: Re: Make COUNT(*) Faster?
In-Reply-To: <1120837111.24708.252.camel@home>
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