Amit Langote <amitlangote09@gmail.com> writes:
> On Thu, Jan 5, 2023 at 4:59 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Here's a draft patch that does it like that. This seems like a win
>> for more reasons than just pruning, because I was able to integrate
>> the calculation into runtime setup of the expressions, so that we
>> aren't doing an extra stringToNode() on them.
> Thanks for the patch. This looks pretty neat and I agree that this
> seems like a net win overall.
Thanks for looking.
>> I've not looked into what it'd take to back-patch this. We can't
>> add a field to ResultRelInfo in released branches (cf 4b3e37993),
>> but we might be able to repurpose RangeTblEntry.extraUpdatedCols.
> I think we can make that work. Would you like me to give that a try?
I'm on it already. AFAICT, the above won't actually work because
we don't have RTEs for all ResultRelInfos (per the
"relinfo->ri_RangeTableIndex != 0" test in ExecGetExtraUpdatedCols).
Probably we need something more like what 4b3e37993 did.
regards, tom lane