Re: checkpoints are duplicated even while the system is idle

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Simon Riggs <simon@2ndquadrant.com>, Fujii Masao <masao.fujii@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2011-10-06T17:58:50Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Thu, Oct 6, 2011 at 12:44 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I think the point is that a totally idle database should not continue to
>> emit WAL, not even at a slow rate. There are also power-consumption
>> objections to allowing the checkpoint process to fire up to no purpose.

> Hmm, OK.  I still think it's a little funny to say that
> checkpoint_timeout will force a checkpoint every N minutes except when
> it doesn't, but maybe there's no real harm in that as long as we
> document it properly.

Well ... if we think that it's sane to only checkpoint once per WAL
segment, maybe we should just take out checkpoint_timeout.

We'd need some other mechanism to address replication use-cases, but see
my comments to Simon's followup patch just now.

			regards, tom lane