Re: cataloguing NOT NULL constraints

Andres Freund <andres@anarazel.de>

From: Andres Freund <andres@anarazel.de>

To: Alvaro Herrera <alvherre@alvh.no-ip.org>

Cc: pgsql-hackers@lists.postgresql.org

Date: 2023-07-01T01:12:08Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Revert structural changes to not-null constraints
- 6f8bb7c1e961 17.0 landed
Fix inconsistencies in error messages
- 21ac38f498b3 17.0 landed
Disallow direct change of NO INHERIT of not-null constraints
- d45597f72fe5 17.0 landed
Disallow NO INHERIT not-null constraints on partitioned tables
- 13daa33fa5a6 17.0 landed
Better handle indirect constraint drops
- 0cd711271d42 17.0 cited
Don't try to assign smart names to constraints
- d72d32f52d26 17.0 cited
Fix restore of not-null constraints with inheritance
- d9f686a72ee9 17.0 landed
ATTACH PARTITION: Don't match a PK with a UNIQUE constraint
- cee8db3f680b 17.0 landed
Fix propagating attnotnull in multiple inheritance
- c3709100be73 17.0 landed
Check stack depth in new recursive functions
- b0f7dd915bca 17.0 landed
Move privilege check to the right place
- ac22a9545ca9 17.0 cited
Update information_schema definition for not-null constraints
- 3af721794272 17.0 landed
Fix not-null constraint test
- d0ec2ddbe088 17.0 landed
Disallow changing NO INHERIT status of a not-null constraint
- 9b581c534186 17.0 cited
Catalog not-null constraints
- b0e96f311985 17.0 cited
parallel_schedule: add comment on event_trigger test dependency
- c8e43c22be27 17.0 landed
Revert "Catalog NOT NULL constraints" and fallout
- 9ce04b50e120 16.0 landed
Adjust contrib/sepgsql regression test expected outputs.
- 76c111a7f166 16.0 landed
Fix table name clash in recently introduced test
- 728015a47016 16.0 landed
Catalog NOT NULL constraints
- e056c557aef4 16.0 landed
Change the rules for inherited CHECK constraints to be essentially the same
- cd902b331dc4 8.4.0 cited

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