From: Andreas Pflug <Andreas.Pflug@web.de>
To: Josh Berkus <josh@agliodbs.com>
To: pgsql-sql@postgresql.org
Subject: Re: Statement triggers 7.4 NEW/OLD
Date: Sat, 26 Apr 2003 10:50:06 +0200
Message-ID: <3EAA483E.2060204@web.de> (raw)
In-Reply-To: <200304252120.01644.josh@agliodbs.com>
References: <3EA7CD6A.9080404@web.de>
<3EA9EFA3.EF4C0D1@Yahoo.com>
<200304252120.01644.josh@agliodbs.com>
Josh Berkus wrote:
>>IMHO statement triggers instead should have access to the NEW and OLD
>>rows through some mechanism. I can think of NEW and OLD being reference
>>cursors in the case of statement triggers, and the trigger then can
>>FETCH the rows from there.
>>
>>
>
>Yeah; how else could it possibly work?
>
>
>
Why do it easy if you can have it difficult? ;-) If I want to perform
row by row actions I use a row level trigger!
Statement triggers need to work like this:
Instead of
NEW.foo := 1;
you code
UPDATE NEW SET foo=1;
If the statement trigger doesn't offer a complete SETOF RECORD, It's
pretty useless.
In my case, updates and deletes on a table could possibly touch
thousands of rows at the same time, and the trigger will update
aggregated values in another table, and insert or delete a third one
with 3-4 additional statements. This is pretty fast if implemented as
true statement trigger, but will possibly blow the system if done row by
row. Imagine a single statement, that triggers ROW_COUNT*4 statements,
where ROW_COUNT can easily be 1000, 10000 or much more!
Regards,
Andreas
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: Andreas.Pflug@web.de, josh@agliodbs.com
Subject: Re: Statement triggers 7.4 NEW/OLD
In-Reply-To: <3EAA483E.2060204@web.de>
* 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