From: Jim C. Nasby <jnasby@pervasive.com>
To: Craig A. James <cjames@modgraph-usa.com>
Cc: PFC <lists@peufeu.com>
Cc: Michael Glaesemann <grzm@myrealbox.com>
Cc: Rodrigo Sakai <rodrigo.sakai@zanthus.com.br>
Cc: pgsql-performance@postgresql.org
Subject: Re: FOREIGN KEYS vs PERFORMANCE
Date: Wed, 12 Apr 2006 10:39:51 -0500
Message-ID: <20060412153951.GH49405@pervasive.com> (raw)
In-Reply-To: <443D127D.2070601@modgraph-usa.com>
References: <001301c65d9c$08884ef0$4700a8c0@TREEZANTHUS>
<72C39159-1A4B-4595-A978-1DF57AD42527@myrealbox.com>
<op.s7vv4ex2cigqcu@apollo13>
<443D127D.2070601@modgraph-usa.com>
On Wed, Apr 12, 2006 at 07:45:17AM -0700, Craig A. James wrote:
> All good advice, but... there are no absolutes in this world.
> Application-enforced referential integrity makes sense if (and probably
> ONLY if):
>
> 1. You have only one application that modifies the data. (Otherwise, you
> have to duplicate the rules across many applications, leading to a
> code-maintenance nightmare).
You forgot something:
1a: You know that there will never, ever, ever, ever, be any other
application that wants to talk to the database.
I know tons of people that get burned because they go with something
that's "good enough for now", and then regret that decision for years to
come.
> 2. If your application crashes and leaves a mess, it's not a catastrophe,
> and you have a good way to clean it up. For example, a bank shouldn't do
> this, but it might be OK for a computer-aided-design application, or the
> backend of a news web site.
>
> 3. You have application-specific knowledge about when you can skip
> referential integrity and thereby greatly improve performance. For
> example, you may have batch operations where large numbers of rows are
> temporarily inconsistent.
>
> If your application doesn't meet ALL of these criteria, you probably should
> use the database for referential integrity.
>
> Craig
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: Have you checked our extensive FAQ?
>
> http://www.postgresql.org/docs/faq
>
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
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To: pgsql-performance@postgresql.org
Cc: jnasby@pervasive.com, cjames@modgraph-usa.com, lists@peufeu.com, grzm@myrealbox.com, rodrigo.sakai@zanthus.com.br
Subject: Re: FOREIGN KEYS vs PERFORMANCE
In-Reply-To: <20060412153951.GH49405@pervasive.com>
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