Sender: tgl@mythos.jpl.nasa.gov
Message-ID: <352CC668.134F4FE7@alumni.caltech.edu>
Date: Thu, 09 Apr 1998 13:00:24 +0000
From: "Thomas G. Lockhart" <lockhart@alumni.caltech.edu>
Organization: Caltech/JPL
MIME-Version: 1.0
To: Maurice Gittens <mgittens@gits.nl>
CC: Massimo Dal Zotto <dz@cs.unitn.it>,
	Pgsql Development <hackers@postgresql.org>, David Gould <dg@illustra.com>
Subject: Re: [HACKERS] Everything leaks; How it mm suppose to work?
References: <00d901bd63a6$a9bd0520$fcf3b2c2@caleb..gits.nl>
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> >Does it make sense to have a 'row' context which is released just 
> >before starting with a new tuple ? The total number or free is the 
> >same but they are distributed over the query and unused memory should 
> >not accumulate.
> >I have seen backends growing to 40-60MB with queries which scan a 
> >very large number of rows.
> I think this would be appropiate.

It seems that the CPU overhead on all queries would increase trying to
deallocate/reuse memory during the query. There are lots of places in
the backend where memory is palloc'd and then left lying around after
use; I had assumed it was sort-of-intentional to avoid having extra
cleanup overhead during a query.

                     - Tom