Re: Support NOT VALID / VALIDATE constraint options for named NOT NULL constraints

On Wed, Mar 12, 2025 at 11:50 PM Alvaro Herrera <alvherre@alvh.no-ip.org>
wrote:

> On 2025-Mar-12, Rushabh Lathia wrote:
>
> > Hi Alvaro,
> >
> > Here are the latest patches, which includes the regression fix.
>
> Thank you.
>
> Taking a step back after discussing this with some colleagues, I need to
> contradict what I said at the start of this thread.  There's a worry
> that changing pg_attribute.attnotnull in the way I initially suggested
> might not be such a great idea after all.  I did a quick search using
> codesearch.debian.net for applications reading that column and thinking
> about how they would react to this change; I think in the end it's going
> to be quite disastrous.  We would break a vast number of these apps, and
> there are probably countless other apps and frameworks that we would
> also break.  Everybody would hate us forever.  Upgrading to Postgres 18
> would become as bad an experience as the drastic change of implicit
> casts to text in 8.3.  Nothing else in the intervening 17 years strikes
> me as so problematic as this change would be.
>
> So I think we may need to go back and somehow leave pg_attribute alone,
> to avoid breaking the whole world.  Maybe it would be sufficient to
> change the CompactAttribute->attnotnull to no longer be a boolean, but
> the new char representation instead.  I'm not sure if this would
> actually work.
>

Thank you for your feedback. I understand that this change could be
problematic

for existing applications, as attnotnull is a highly generic catalog
column. I will

revisit the patch, make the necessary adjustments, and submit a revised
version

accordingly.


I appreciate your insights and will try to submit the new patch.



Regards,
Rushabh Lathia
www.EnterpriseDB.com