Sender: root@dune.krasnet.ru
Message-ID: <3545378B.C6263F16@sable.krasnoyarsk.su>
Date: Tue, 28 Apr 1998 09:57:31 +0800
From: "Vadim B. Mikheev" <vadim@sable.krasnoyarsk.su>
Organization: ITTS (Krasnoyarsk)
MIME-Version: 1.0
To: Byron Nikolaidis <byronn@insightdist.com>
CC: "pgsql-interfaces@postgreSQL.org" <pgsql-interfaces@postgreSQL.org>,
	Sbragion Denis <infotecn@tin.it>,
	"pgsql-hackers@postgreSQL.org" <pgsql-hackers@postgreSQL.org>,
	Olaf Mittelstaedt <mstaedt@va-sigi.va.fh-ulm.de>,
	Hannu Krosing <hannu@trust.ee>
Subject: Re: [HACKERS] New Driver and Unique Indexes
References: <3544D6E7.3211AAB4@insightdist.com>
Content-Type: text/plain; charset=koi8-r
Content-Transfer-Encoding: 7bit

Byron Nikolaidis wrote:
> 
> SELECT balance_id,company_id, balance_date, is_audited,comment,
> balance_type, balance_filename  FROM balance  WHERE balance_id = 1 AND
> company_id=1 OR balance_id = 1 AND company_id=2 OR balance_id = 1 AND
> company_id=3 OR balance_id = 2 AND company_id=1 OR balance_id = 2 AND
> company_id=2 OR balance_id = 2 AND company_id=3 OR balance_id = 3 AND
> company_id=1 OR balance_id = 3 AND company_id=2 OR balance_id = 3 AND
> company_id=3 OR balance_id = 4 AND company_id=1
> 
> Any more than 2 keyparts, results in crashing the backend with the
> message
> "palloc failure:  memory exhausted".  Even at 2 keyparts, performance
> suffers greatly.

THis is known problem of canonificator in optimizer. This query will 
crash backend without any indices too.
We told about this in the 6.3-beta period.
No fix currently. I don't know when it will be at all.

Vadim