Re: cataloguing NOT NULL constraints

Hi,

On 2023-06-30 13:44:03 +0200, Alvaro Herrera wrote:
> OK, so here's a new attempt to get this working correctly.

Thanks for continuing to work on this!

> The main novelty in this version of the patch, is that we now emit
> "throwaway" NOT NULL constraints when a column is part of the primary
> key. Then, after the PK is created, we run a DROP for that constraint.
> That lets us create the PK without having to scan the table during
> pg_upgrade.

Have you considered extending the DDL statement for this purpose? We have
ALTER TABLE ... ADD CONSTRAINT ... PRIMARY KEY USING INDEX ...;
we could just do something similar for the NOT NULL constraint? Which would
then delete the separate constraint NOT NULL constraint.

Greetings,

Andres Freund