On Sat, Jul 18, 2020 at 3:04 PM Jeff Davis <pgsql@j-davis.com> wrote:
> > I think the entire discussion
> > is way out ahead of any field evidence that we need such a knob.
> > In the absence of evidence, our default position ought to be to
> > keep it simple, not to accumulate backwards-compatibility kluges.
>
> Fair enough. I think that was where Stephen and Amit were coming from,
> as well.
> That would lessen the number of changed plans, but we could easily
> remove the pessimization without controversy later if it turned out to
> be unnecessary, or if we further optimize HashAgg IO.
Does this mean that we've reached a final conclusion on
hashagg_avoid_disk_plan for Postgres 13, which is that it should be
removed? If so, I'd appreciate it if you took care of it. I don't
think that we need to delay its removal until the details of the
HashAgg cost pessimization are finalized. (I expect that that will be
totally uncontroversial.)
Thanks
--
Peter Geoghegan