Re: Wrong results with subquery pullup and grouping sets

On Wed, 12 Mar 2025 at 07:45, Richard Guo <guofenglinux@gmail.com> wrote:
>
> I refined the comment in v2 and ended up with:
>
>       * This analysis could be tighter: in particular, a non-strict
>       * construct hidden within a lower-level PlaceHolderVar is not
>       * reason to add another PHV.  But for now it doesn't seem
> -     * worth the code to be more exact.
> +     * worth the code to be more exact.  This is also why it's
> +     * preferable to handle bare PHVs in the above branch, rather
> +     * than this branch.  We also prefer to handle bare Vars in a
> +     * separate branch, as it's cheaper this way and parallels the
> +     * handling of PHVs.
>

LGTM.

> For backpatching, 0001 seems more like a cosmetic change, and I don't
> think it needs to be backpatched.  0002 is a bug fix, but I'm not
> confident enough to commit it to the back branches.  Given that there
> are other wrong result issues with grouping sets fixed in version 18
> but not in earlier versions, and that there are no field reports about
> this issue, perhaps it's OK to refrain from backpatching this one?
>

Yes, I was thinking along the same lines. This particular issue feels
a bit manufactured, and unlikely to occur in practice, but I'm happy
to go with whatever you decide.

Thanks for taking care of this.

Regards,
Dean