On Tue, May 23, 2023 at 11:54:30PM -0400, Bruce Momjian wrote:
> On Wed, May 24, 2023 at 08:37:45AM +1200, David Rowley wrote:
> > On Mon, 22 May 2023 at 07:05, Jonathan S. Katz <jkatz@postgresql.org> wrote:
> > > * Parallel execution of queries that use `FULL` and `OUTER` joins
> >
> > I think this should be `RIGHT` joins rather than `OUTER` joins.
> >
> > LEFT joins have been parallelizable I think for a long time now.
>
> Well, since we can swap left/right easily, why would we not have just
> have swappted the tables and done the join in the past? I think there
> are two things missing in my description.
>
> 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 went with this text:
Allow parallelization of FULL and internal right OUTER hash joins
(Melanie Plageman, Thomas Munro)
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
Only you can decide what is important to you.