To: Stephan Szabo <sszabo@megazone.bigpanda.com>
Cc: Simon Riggs <simon@2ndquadrant.com>,
 Karim A Nassar <Karim.Nassar@NAU.EDU>,
	Christopher Kings-Lynne <chriskl@familyhealth.com.au>,
	pgsql-performance@postgresql.org
Subject: Re: Delete query takes exorbitant amount of time 
In-reply-to: <20050329061837.A51620@megazone.bigpanda.com> 
References: <Pine.SOL.4.21.0503290120550.5642-100000@coruscant.cet.nau.edu>
	<1112095776.11750.958.camel@localhost.localdomain>
	<20050329054714.V50612@megazone.bigpanda.com>
	<20050329061837.A51620@megazone.bigpanda.com>
Comments: In-reply-to Stephan Szabo <sszabo@megazone.bigpanda.com>
	message dated "Tue, 29 Mar 2005 06:20:25 -0800"
Date: Tue, 29 Mar 2005 09:56:41 -0500
Message-ID: <21616.1112108201@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Stephan Szabo <sszabo@megazone.bigpanda.com> writes:
> If there were some way to pass a "limit" into SPI_prepare that was treated
> similarly to a LIMIT clause for planning purposes but didn't actually
> change the output plan to only return that number of rows, we could use
> that.

Hmm ... the planner does have the ability to do that sort of thing (we
use it for cursors).  SPI_prepare doesn't expose the capability.
Perhaps adding a SPI_prepare variant that does expose it would be the
quickest route to a solution.

I get a headache every time I look at the RI triggers ;-).  Do they
always know at the time of preparing a plan which way it will be used?

			regards, tom lane