X-Original-To: pgsql-sql-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.2])
	by svr1.postgresql.org (Postfix) with ESMTP id 2784AD1B57C
	for <pgsql-sql-postgresql.org@localhost.postgresql.org>;
	Fri, 13 Feb 2004 13:57:25 +0000 (GMT)
Received: from svr1.postgresql.org ([200.46.204.71])
	by localhost (neptune.hub.org [200.46.204.2]) (amavisd-new, port 10024)
	with ESMTP id 83523-08
	for <pgsql-sql-postgresql.org@localhost.postgresql.org>;
	Fri, 13 Feb 2004 09:57:25 -0400 (AST)
Received: from tht.net (vista.tht.net [216.126.88.2])
	by svr1.postgresql.org (Postfix) with ESMTP id A4CD9D1B4E1
	for <pgsql-sql@postgresql.org>; Fri, 13 Feb 2004 09:57:21 -0400 (AST)
Received: from [134.22.71.135] (dyn-71-135.tor.dsl.tht.net [134.22.71.135])
	by tht.net (Postfix) with ESMTP
	id 03A7176C38; Fri, 13 Feb 2004 08:57:26 -0500 (EST)
Subject: Re: 7.4 - FK constraint performance
From: Rod Taylor <rbt@rbt.ca>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: ow <oneway_111@yahoo.com>, pgsql-sql@postgresql.org
In-Reply-To: <27443.1076646336@sss.pgh.pa.us>
References: <20040213010341.95282.qmail@web60801.mail.yahoo.com>
	<25808.1076634636@sss.pgh.pa.us> <1076640825.10896.12.camel@jester>
	<27443.1076646336@sss.pgh.pa.us>
Content-Type: multipart/signed; micalg=pgp-sha1;
	protocol="application/pgp-signature";
	boundary="=-iNtOxgRRscvvxZOusvVc"
Message-Id: <1076680669.10896.17.camel@jester>
Mime-Version: 1.0
X-Mailer: Ximian Evolution 1.4.5 
Date: Fri, 13 Feb 2004 08:57:50 -0500
X-Virus-Scanned: by amavisd-new at postgresql.org
X-Archive-Number: 200402/157
X-Sequence-Number: 16848

--=-iNtOxgRRscvvxZOusvVc
Content-Type: text/plain
Content-Transfer-Encoding: quoted-printable

On Thu, 2004-02-12 at 23:25, Tom Lane wrote:
> Rod Taylor <rbt@rbt.ca> writes:
> > Statistics say there are 10 values. Statistics list the 10 most common
> > values (all of them). Given this, would it not be reasonable to assume
> > that 239 is a recent addition (if there at all) to the table and not
> > very common?
>=20
> We don't know that it's 239 when we make the plan.  In order to know
> that, we'd have to abandon caching of RI check query plans and re-plan
> for each row.  That strikes me as inevitably a losing proposition.

Right, sorry, I forgot this was out of a fk trigger.

--=20
Rod Taylor <rbt [at] rbt [dot] ca>

Build A Brighter Lamp :: Linux Apache {middleware} PostgreSQL
PGP Key: http://www.rbt.ca/rbtpub.asc

--=-iNtOxgRRscvvxZOusvVc
Content-Type: application/pgp-signature; name=signature.asc
Content-Description: This is a digitally signed message part

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.4 (FreeBSD)

iD8DBQBALNfd6DETLow6vwwRAivsAKCBVxZ0178LqnZgW13bp0gSrCjUoACePEOX
1qVYXQRYKS004tjy/d/UCuU=
=CDq8
-----END PGP SIGNATURE-----

--=-iNtOxgRRscvvxZOusvVc--