Re: Allowing join removals for more join types

David Rowley <dgrowleyml@gmail.com> writes:
> I've attached an updated patch which puts in some fast path code for
> subquery type joins. I'm really not too sure on a good name for this
> function. I've ended up with query_supports_distinctness() which I'm not
> that keen on, but I didn't manage to come up with anything better.

I've committed this with some mostly but not entirely cosmetic changes.

Notably, I felt that pathnode.c was a pretty questionable place to be
exporting distinctness-proof logic from, and after some reflection decided
to move those functions to analyzejoins.c; that's certainly a better place
for them than pathnode.c, and I don't see any superior third alternative.