Re: Add red-black tree missing comparison searches

Hi, Steve!

Thank you for working on this.

On Thu, Jun 30, 2022 at 7:51 PM Steve Chavez <steve@supabase.io> wrote:
> Currently the red-black tree implementation only has an equality search. Other extensions might need other comparison searches, like less-or-equal or greater-or-equal. For example OrioleDB defines a greater-or-equal search on its postgres fork:
>
> https://github.com/orioledb/postgres/blob/4c18ae94c20e3e95c374b9947f1ace7d1d6497a1/src/backend/lib/rbtree.c#L164-L186
>
> So I thought this might be valuable to have in core. I've added less-or-equal and greater-or-equal searches functions plus tests in the test_rbtree module. I can add the remaining less/great searches if this is deemed worth it.

Looks good.  But I think we can support strict inequalities too (e.g.
less and greater without equals).  Could you please make it a bool
argument equal_matches?

> Also I refactored the sentinel used in the rbtree.c to use C99 designators.

Could you please extract this change as a separate patch.

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Regards,
Alexander Korotkov