From: Josh Berkus <josh@agliodbs.com>
To: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: Jean-Luc Lachance <jllachan@nsd.ca>
Cc: pgsql-sql <pgsql-sql@postgresql.org>
Subject: Re: Rules/Trigges Trade-offs
Date: Fri, 6 Dec 2002 15:54:07 -0800
Message-ID: <200212061554.07415.josh@agliodbs.com> (raw)
In-Reply-To: <200212062330.gB6NUDl20018@candle.pha.pa.us>
References: <200212062330.gB6NUDl20018@candle.pha.pa.us>
Bruce,
> > 1) Rules can't use indexes to do their processing, so Rules which query
large
> > secondary tables can be a bad idea (maybe this has changed?)
>
> I don't think this is true. Rewrite is before optimizer so it should be
> optimized just the same.
I was speaking if the Rule has to do a lookup on a 2nd table in the course of
its processing; it used to be that such a lookup could not use indexes
because Rules are pre-optimizer. This could have changed since 7.1, though.
> > 3) There are no AFTER Rules, making, for example, a rule with a table
check on
> > the new data impractical, so you'd want to use Triggers or Constraints
>
> We have changed ordering in 7.3 where I think INSERT rules are _after_
> the insert.
How would that work? What if I want to reject the insert?
--
-Josh Berkus
Aglio Database Solutions
San Francisco
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: josh@agliodbs.com, pgman@candle.pha.pa.us, jllachan@nsd.ca
Subject: Re: Rules/Trigges Trade-offs
In-Reply-To: <200212061554.07415.josh@agliodbs.com>
* 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