From: Mattias Kregert <mattias@kregert.se>
To: Steinar H. Gunderson <sgunderson@bigfoot.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Strange plan in pg 8.1.0
Date: Mon, 30 Oct 2006 15:26:09 +0100
Message-ID: <003301c6fc2f$57e2c660$09000a0a@kregert.se> (raw)
References: <200610301205.08087.mattias@kregert.se>
<20061030122733.GA6357@uio.no>
>>> From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
> On Mon, Oct 30, 2006 at 01:05:07PM +0200, Mattias Kregert wrote:
>> -> Hash Left Join (cost=59.66..206763.11 rows=1215336
>> width=27) (actual time=4.959..3228.550 rows=1216434 loops=1)
>> Hash Cond: (("outer".prislista = ("inner".listid)::text)
>> AND ("outer".tjanst = ("inner".tjanstid)::text))
>
> Note the conversion to text here. Are you sure the types are matching on
> both
> sides of the join?
>
> /* Steinar */
On the left side it is text, and on the right side it is varchar(10).
Casting left side to varchar(10) does not help, in fact it makes things even
worse: The cast to ::text vanishes in a puff of logic, but the plan gets
bigger and even slower (20-25 seconds).
A RIGHT join takes only 20 milliseconds, but i want the left join because
there could be missing rows in the "prislist" table...
/* m */
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To: pgsql-performance@postgresql.org
Cc: mattias@kregert.se, sgunderson@bigfoot.com
Subject: Re: Strange plan in pg 8.1.0
In-Reply-To: <003301c6fc2f$57e2c660$09000a0a@kregert.se>
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