Re: Auto-tuning work_mem and maintenance_work_mem

* Peter Geoghegan (pg@heroku.com) wrote:
> On Wed, Oct 9, 2013 at 7:11 PM, Stephen Frost <sfrost@snowman.net> wrote:
> > There is definitely something to be said for simplicity and just up'ing
> > the default would have a more dramatic impact with a setting like
> > work_mem than it would with shared_buffers, imv.
>
> Simplicity for us or for our users?

My thinking was 'both', really.

> I wonder if we should just ship something like pgtune (in /bin, not in
> /contrib) that can be optionally used at initdb time. Making something
> like wal_buffers self-tuning is really compelling, but work_mem is
> quite different.

I'm coming around to agree with this also- doing this at initdb time
really makes more sense than during server start-up based on some
(mostly) unrelated value.

> I hear a lot of complaints about "the first 15 minutes experience" of
> Postgres. It's easy to scoff at this kind of thing, but I think we
> could do a lot better there, and at no real cost - the major blocker
> to doing something like that has been fixed (of course, I refer to the
> SysV shared memory limits). Is the person on a very small box where
> our current very conservative defaults are appropriate? Why not ask a
> few high-level questions like that to get inexperienced users started?

There are certainly challenges here wrt asking questions during install,
as was mentioned elsewhere, but I agree that we could do better.

> The tool could even have a parameter that allows a packager to pass
> total system memory without bothering the user with that, and without
> bothering us with having to figure out a way to make that work
> correctly and portably.

Agreed.
Thanks,
    Stephen