From: Rod Taylor <rbt@rbt.ca>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: ow <oneway_111@yahoo.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: 7.4 - FK constraint performance
Date: Fri, 13 Feb 2004 08:57:50 -0500
Message-ID: <1076680669.10896.17.camel@jester> (raw)
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>
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?
>
> 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.
--
Rod Taylor <rbt [at] rbt [dot] ca>
Build A Brighter Lamp :: Linux Apache {middleware} PostgreSQL
PGP Key: http://www.rbt.ca/rbtpub.ascAttachments:
signature.asc (application/pgp-signature, 186B) download
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-sql@postgresql.org
Cc: rbt@rbt.ca, tgl@sss.pgh.pa.us, oneway_111@yahoo.com
Subject: Re: 7.4 - FK constraint performance
In-Reply-To: <1076680669.10896.17.camel@jester>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox