Re: Auto-tuning work_mem and maintenance_work_mem

On Wed, Oct 9, 2013 at 06:20:13PM +0200, Pavel Stehule wrote:
> On Wed, Oct  9, 2013 at 05:01:24PM +0200, Pavel Stehule wrote:
> >     FYI, this auto-tuning is not for us, who understand the parameters
> and
> >     how they interact, but for the 90% of our users who would benefit
> from
> >     better defaults.  It is true that there might now be cases where you
> >     would need to _reduce_ work_mem from its default, but I think the new
> >     computed default will be better for most users.
> >
> >
> >
> > then we should to use as base a how much dedicated RAM is for PG - not
> shared
> > buffers.
>
> Yes, that was Josh Berkus's suggestion, and we can switch to that,
> though it requires a new GUC parameter, and then shared_buffers gets
> tuned on that.
>
> I went with shared_buffers because unlike the others, it is a fixed
> allocation quantity, while the other are much more variable and harder
> to set.  I figured we could keep our 25% estimate of shared_buffers and
> everything else would fall in line.
>
>
> I understand, but your proposal change a logic to opposite direction. Maybe
> better is wait to new GUC parameter, and then implement this feature, so be
> logical and simply understandable.

OK, I can easily do that. What do others think?

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ Everyone has their own god. +