Richard Guo <guofenglinux(at)gmail(dot)com> writes:
> Attached is a patch to not rely on DISTINCT ON for distinctness if
> there are any tlist SRFs. This is more conservative than necessary,
> since the SRFs are only postponed when there is an ORDER BY and none
> of them is in a sort/group column, but I don't think it's worth
> duplicating that logic in analyzejoins.c.
I didn't study the patch in any detail, but I concur with your
thinking here. SRFs in the tlist are kind of a legacy usage in the
first place, so I don't feel a need to expend lots of effort on
optimizing cases like this.
regards, tom lane