Re: Correction of RowMark Removal During Sel-Join Elimination

On Sat, Aug 30, 2025 at 4:00 PM Alexander Lakhin <exclusion(at)gmail(dot)com> wrote:
>
> Hello Alexander,
>
> 24.08.2025 03:44, Alexander Korotkov wrote:
>
> Thank you for catching this. And thank you for the fix. I think it
> worth separating fix and refactoring. This helps to understand what
> exactly the fix is by looking at the patch. I also edited commit
> message. I'm going to push this if no objections.
>
>
> Please try the following script:
> create table t1(i1 int primary key);
> create table t2 (i2 int, check (i2 is not null));
>
> set constraint_exclusion = 'on';
>
> select 1 from t1 right join t2 on i1 = i2 where (select true);
>
> which triggers (starting from 5f6f951f8):
> Core was generated by `postgres: law regression [local] SELECT '.
> Program terminated with signal SIGSEGV, Segmentation fault.
> #0 0x000058dd6a7b6014 in var_is_nonnullable (root=0x58dd78d505f8, var=0x58dd78d75610, use_rel_info=false) at clauses.c:4242
> 4242 if (rte->inh && rte->relkind != RELKIND_PARTITIONED_TABLE)
> (gdb) bt
> #0 0x000058dd6a7b6014 in var_is_nonnullable (root=0x58dd78d505f8, var=0x58dd78d75610, use_rel_info=false) at clauses.c:4242
> #1 0x000058dd6a7b4f74 in eval_const_expressions_mutator (node=0x58dd78d75590, context=0x7fff875a9f00) at clauses.c:3556
> #2 0x000058dd6a7b2935 in eval_const_expressions (root=0x58dd78d505f8, node=0x58dd78d75590) at clauses.c:2272
> #3 0x000058dd6a7c857d in get_relation_constraints (root=0x58dd78d505f8, relationObjectId=16385, rel=0x58dd78d738e0, include_noinherit=true, include_notnull=true, include_partition=true) at plancat.c:1419
> #4 0x000058dd6a7c8fdb in relation_excluded_by_constraints (root=0x58dd78d505f8, rel=0x58dd78d738e0, rte=0x58dd78c6b968) at plancat.c:1808
> #5 0x000058dd6a73675e in set_rel_size (root=0x58dd78d505f8, rel=0x58dd78d738e0, rti=2, rte=0x58dd78c6b968) at allpaths.c:364
> #6 0x000058dd6a73664c in set_base_rel_sizes (root=0x58dd78d505f8) at allpaths.c:322
> #7 0x000058dd6a73631e in make_one_rel (root=0x58dd78d505f8, joinlist=0x58dd78d74a90) at allpaths.c:183

Thank you for pointing. I'm investigating this now.

------
Regards,
Alexander Korotkov
Supabase