Re: PG 16 draft release notes ready

On Wed, May 24, 2023 at 04:13:14PM +1200, David Rowley wrote:
> On Wed, 24 May 2023 at 15:54, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> > First, I need to mention parallel _hash_ join. Second, I think this
> > item is saying that the _inner_ side of a parallel hash join can be an
> > OUTER or FULL join. How about?
> >
> > Allow hash joins to be parallelized where the inner side is
> > processed as an OUTER or FULL join (Melanie Plageman, Thomas Munro)
> >
> > In this case, the inner side is the hashed side.
>
> I think Jonathan's text is safe to swap OUTER to RIGHT as it mentions
> "execution". For the release notes, maybe the mention of it can be
> moved away from "E.1.3.1.1. Optimizer" and put under "E.1.3.1.2.
> General Performance" and ensure we mention that we're talking about
> the executor?
>
> I'm thinking it might be confusing if we claim that this is something
> that we switched on in the planner. It was a limitation with the
> executor which the planner was just onboard with not producing plans
> for.

Well, I try to keep plan changes in the optimizer section because that
is where the decisions are made, and how people think of plans since
EXPLAIN makes them visible. I agree it is an executor change but I
think that distinction will be more confusing than helpful.

Frankly, almost all the optimizer items are really executor changes.
Maybe the "Optimizer" title needs to be changed, but I do think it is
good to group plan changes together.

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

Only you can decide what is important to you.