Re: Todo: Teach planner to evaluate multiple windows in the optimal order

On Sat, Jan 28, 2023 at 3:21 PM Ankit Kumar Pandey <itsankitkp(at)gmail(dot)com>
wrote:
>
> > On 26/01/23 07:40, David Rowley wrote:

> > We might want to look at 1) Expanding
> > on what 69749243 did and considering if we want sort specialisations
> > that are specifically for 1 column and another set for multi-columns.
> > The multi-column ones don't need to re-compare key[0] again. 2)
> > Sorting in smaller batches that better fit into CPU cache. Both of
> > these ideas would require a large amount of testing and discussion.
> > For #1 we're considering other specialisations, for example NOT NULL,
> > and we don't want to explode the number of specialisations we have to
> > compile into the binary.
>
> Yes, 1 & 2 needs to be addressed before going ahead with this patch.
> Do we any have ongoing thread with #1 and #2?

I recently brought up this older thread (mostly about #1), partly because
of the issues discovered above, and partly because I hope to make progress
on it before feature freeze (likely early April):

https://www.postgresql.org/message-id/CAApHDvqXcmzAZDsj8iQs84%2Bdrzo0PgYub_QYzT6Zdj6p4A3A5A%40mail.gmail.com

--
John Naylor
EDB: http://www.enterprisedb.com