From: Steinar H. Gunderson <sgunderson@bigfoot.com>
To: pgsql-performance@postgresql.org
Subject: Re: is it possible to make this faster?
Date: Thu, 25 May 2006 23:08:50 +0200
Message-ID: <20060525210850.GA20274@uio.no> (raw)
In-Reply-To: <b42b73150605251354j283af4d3i3f24143d26230094@mail.gmail.com>
References: <b42b73150605251307id0e7998td4a3693f0d456f88@mail.gmail.com>
<20060525203630.GA19881@uio.no>
<b42b73150605251354j283af4d3i3f24143d26230094@mail.gmail.com>
On Thu, May 25, 2006 at 04:54:09PM -0400, Merlin Moncure wrote:
>> select a,b,(select c from t t2 order by c desc where t1.a=t2.a and
>> t1.b=t2.b)
>> from t t1 group by a,b;
> this came out to a tie with the group by approach, although it
> produced a different (but similar) plan. we are still orders of
> magnitude behind mysql here.
Actually, it _should_ produce a syntax error -- it's missing a LIMIT 1 in the
subquery.
/* Steinar */
--
Homepage: http://www.sesse.net/
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To: pgsql-performance@postgresql.org
Cc: sgunderson@bigfoot.com
Subject: Re: is it possible to make this faster?
In-Reply-To: <20060525210850.GA20274@uio.no>
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