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

On 30/10/2023 09:24, Richard Guo wrote:
> 
> On Sun, Oct 29, 2023 at 11:56 PM Tom Lane <tgl@sss.pgh.pa.us 
> <mailto:tgl@sss.pgh.pa.us>> wrote:
> 
>     Alexander Korotkov <aekorotkov@gmail.com
>     <mailto: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.

It is not about unchanged; it is about referencing the same query at the 
parent and child query blocks. Am I missing something?

-- 
regards,
Andrei Lepikhov
Postgres Professional