Re: [HACKERS] []performance issues

From: Andrew Sullivan <andrew(at)libertyrms(dot)info>
To: PostgreSQL general list <pgsql-general(at)postgresql(dot)org>
Subject: Re: [HACKERS] []performance issues
Date: 2002-08-06 21:45:00
Message-ID: 20020806174500.C29630@mail.libertyrms.com
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On Fri, Aug 02, 2002 at 02:08:02PM -0400, Rod Taylor wrote:
>
> Of course, as suggested this is easily overcome by keeping your own c
> counter.
>
> begin;
> insert into bigtable values ();
> update into counttable set count=count+1;
> commit;
>
> Now you get all the fun concurrency issues -- but fetching the
> information will be quick. What happens more, the counts, or the
> inserts :)

You could get around this with a trigger that just inserts 1 into one
table (call it counter_unposted), and then using an external process
to take those units, add them to the value in counter_posted, and
delete them from counter_unposted. You'd always be a few minutes
behind, but you'd get a counter that's pretty close without too much
overhead. Of course, this raises the obvious question: why use
count() at all?

A

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Andrew Sullivan 87 Mowat Avenue
Liberty RMS Toronto, Ontario Canada
<andrew(at)libertyrms(dot)info> M6K 3E3
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