Re: NOT ENFORCED constraint feature - Mailing list pgsql-hackers

On Wed, Mar 26, 2025 at 12:29 PM Álvaro Herrera <alvherre@alvh.no-ip.org> wrote:
>
> On 2025-Mar-26, Amul Sul wrote:
>
> > The reason for the change is to revert to the behavior before commit
> > #80d7f990496b1c, where recursion occurred regardless of the
> > changed flags. This is also described in the header comment for
> > ATExecAlterConstrDeferrability() (earlier it was for
> > ATExecAlterConstraintInternal):
> >
> >  * Note that we must recurse even when the values are correct, in case
> >  * indirect descendants have had their constraints altered locally.
> >  * (This could be avoided if we forbade altering constraints in partitions
> >  * but existing releases don't do that.)
>
> Umm, why?  Surely we should not allow a partition tree to become
> inconsistent.
>

I just checked, and we are not allowed to alter a constraint on the
child table alone, nor can we merge it when attaching to the parent
constraint if the deferrability is different. Therefore, I think we
should remove this comment as it seems outdated now.

Regards,
Amul