Re: checkpoints are duplicated even while the system is idle

On 06.10.2011 20:58, Tom Lane wrote:
> 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.

Huh? Surely not, in my mind checkpoint_timeout is the primary way of 
controlling checkpoints, and checkpoint_segments you just set "high 
enough" so that you never reach it.

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com