To: Mark Lewis <mark.lewis@mir3.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Delete query takes exorbitant amount of time 
In-reply-to: <1111713798.23412.3.camel@amateljan.mirlogic.com> 
References: <1111709457.9085.127.camel@k2.cet.nau.edu>
	<2630.1111711927@sss.pgh.pa.us>
	<1111713798.23412.3.camel@amateljan.mirlogic.com>
Comments: In-reply-to Mark Lewis <mark.lewis@mir3.com>
	message dated "Thu, 24 Mar 2005 17:23:19 -0800"
Date: Thu, 24 Mar 2005 21:32:56 -0500
Message-ID: <4009.1111717976@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Mark Lewis <mark.lewis@mir3.com> writes:
> I've got a similar problem with deletes taking a very long time.  I know
> that there are lots of foreign keys referencing this table, and other
> foreign keys referencing those tables, etc.  I've been curious, is there
> a way to find out how long the foreign key checks take for each
> dependent table?

There is not any easy way at the moment.

Hmm ... I wonder how hard it would be to teach EXPLAIN ANALYZE to show
the runtime expended in each trigger when the statement is of a kind
that has triggers.  We couldn't break down the time *within* the
triggers, but even this info would help a lot in terms of finger
pointing ...

	Seq Scan on ... (nn.nnn ms)
	Trigger foo: nn.mmm ms
	Trigger bar: nn.mmm ms
	Total time: nn.mmm ms

			regards, tom lane