Re: shared_buffers documentation

Robert Haas wrote:
> On Mon, Apr 19, 2010 at 5:36 PM, Bruce Momjian <bruce@momjian.us> wrote:
> >> I don't actually know what's best. ?I'm just concerned that we have a
> >> default in postgresql.conf and a tuning guide that says "don't do
> >> that". ?Maybe the tuning guide needs to be more nuanced, or maybe
> >> postgresql.conf needs to be changed, but it makes no sense to have
> >> them saying contradictory things.
> >
> > The good news about checkpoint_segments is that you get a log file
> > warning message if the value should be increased, i.e. you are
> > checkpointing often than 30 seconds.
> 
> Yeah.  I get that warning frequently when I'm creating test tables of
> dummy data for PG devel purposes.  That's actually the main thing that
> makes me think the default may be too low.

Well, the point is that you are getting it for _unusual_ circumstances. 
Seems it is only when you are getting it for typical workloads that it
should be increased.  However, this is the first time I am hearing that
battery-backed cache favors the default value.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com