Re: gprof SELECT COUNT(*) results

From: Simon Riggs <simon(at)2ndquadrant(dot)com>
To: Qingqing Zhou <zhouqq(at)cs(dot)toronto(dot)edu>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: gprof SELECT COUNT(*) results
Date: 2005-11-26 12:39:21
Message-ID: 1133008761.2906.121.camel@localhost.localdomain
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On Sat, 2005-11-26 at 03:13 -0500, Qingqing Zhou wrote:
> "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote
> >
> > I plan to take a look at it soon.
> >
>
> "Stand corrected"[Merlin]! In-memory "SELECT COUNT(*)" doubles the
> performance due to my test.
>
> - before -
> 1.56 s
>
> - now -
> 0.72 s
>

...and for emphasis: this optimization of SeqScans is not possible with
any other database system, so its a big win for PostgreSQL.

Best Regards, Simon Riggs

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