Re: BUG #18170: Unexpected error: no relation entry for relid 3

On Mon, Oct 30, 2023 at 4:24 AM Richard Guo <guofenglinux@gmail.com> wrote:
>
> On Sun, Oct 29, 2023 at 11:56 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>
>> Alexander Korotkov <aekorotkov@gmail.com> writes:
>> > I made some beautification of the patch by Andrei.  I also removed the
>> > part which changes the target list for estimate_num_groups().  Any
>> > objections to pushing this?
>>
>> It seems moderately likely that this will break as much as it fixes.
>>
>> I've not studied the original patch enough to understand why you need
>> to be playing strange games with tree mutation rules, but I suspect
>> that this is band-aiding over some rather fundamentally bad code.
>
>
> I also have some concerns about this patch.  It requires that
> root->parse remains unchanged during the whole subquery_planner() in
> order to work, which is an implicit constraint we did not have before.

I wouldn't say this is exactly what is required.  Actually, the patch
requires root->parse and corresponding
parent_root->simple_rte_array[]->subquery to be the same.  So, it's
still possible to change both of them, but just don't make them
distinct copies.

------
Regards,
Alexander Korotkov