Re: Pathify RHS unique-ification for semijoin planning

On Tue, Aug 12, 2025 at 10:43 AM Richard Guo <guofenglinux(at)gmail(dot)com> wrote:
> On Mon, Aug 4, 2025 at 11:08 AM Richard Guo <guofenglinux(at)gmail(dot)com> wrote:
> > The v5 patch does not apply anymore, and here is a new rebase. There
> > are two main changes in v6:
> >
> > * I choose to use the check I proposed earlier to determine whether a
> > relation has been unique-ified in costsize.c.
> >
> > * Now that the only call to relation_has_unique_index_for() that
> > supplied an exprlist and oprlist has been removed, the loop handling
> > those lists is effectively dead code. 0002 removes that loop and
> > simplifies the function accordingly.

> Does anyone plan to review this patch further? I intend to push it in
> two weeks unless there are any objections or additional comments.

Here's the updated version of the patch, which renames the macro
IS_UNIQUEIFIED_REL to RELATION_WAS_MADE_UNIQUE, and includes some
comment updates as well. I plan to push it soon, barring any
objections.

This patch removes the last call to make_sort_from_sortclauses(), so
I'm wondering if we can safely remove the function itself. Or should
we keep it around in case it's used by extensions or might be needed
in the future?

Thanks
Richard