Date: Mon, 28 Aug 2006 10:27:31 -0400
From: Alvaro Herrera <alvherre@commandprompt.com>
To: Andrew Sullivan <ajs@crankycanuck.ca>
Cc: pgsql-sql@postgresql.org
Subject: Re: Create Assertion -- Question from a newbie
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Andrew Sullivan wrote:
> On Sun, Aug 27, 2006 at 07:39:49AM -0700, Richard Broersma Jr wrote:
> 
> > Ah, I see.  So the points is that checking the integrity between
> > two complete data sets can become a preformace killer.
> 
> Not necessarily.  More exactly, building a support system that can
> check such integrity in a completely general way, such that it could
> be used for any arbitrary data, is a hard problem that might destroy
> performance.  It's also a pretty exotic feature.  You might want to
> ask on the -hackers list for more detail, though.

Well, it's on the SQL standard, so we should look forward to
implementing (some form of) it some day.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support