Date: Thu, 10 Jan 2008 14:47:05 -0300
From: Alvaro Herrera <alvherre@commandprompt.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Gerardo Herzig <gherzig@fmed.uba.ar>,
	Pavel Stehule <pavel.stehule@gmail.com>,
	Chris Browne <cbbrowne@acm.org>, pgsql-sql@postgresql.org
Subject: Re: trigger for TRUNCATE?
Message-ID: <20080110174705.GO6465@alvh.no-ip.org>
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Tom Lane escribiÃ³:
> Alvaro Herrera <alvherre@commandprompt.com> writes:
> > Gerardo Herzig escribió:
> >> Yes, the TRUNCATE statement is not sql ansi, maybe is a more low level 
> >> thing than i think.
> 
> > TRUNCATE currently does not fire triggers, but that doesn't mean it's
> > impossible to do it.  I think it would be fairly easy to add support
> > for that.
> 
> The entire point of TRUNCATE is to not do a table scan, so making it
> fire per-row triggers seems pretty misguided to me.

My thinking is that a TRUNCATE trigger is a per-statement trigger which
doesn't have access to the set of deleted rows (Replicator uses it that
way -- we replicate the truncate action, and replay it on the replica).
In that way it would be different from a per-statement trigger for
DELETE.

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