Horton

Re: cataloguing NOT NULL constraints

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

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Michael Paquier <michael@paquier.xyz>
Cc: Alexander Lakhin <exclusion@gmail.com>, Dean Rasheed <dean.a.rasheed@gmail.com>, Peter Eisentraut <peter@eisentraut.org>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2024-02-05T14:47:19Z
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 →

  1. Revert structural changes to not-null constraints

  2. Fix inconsistencies in error messages

  3. Disallow direct change of NO INHERIT of not-null constraints

  4. Disallow NO INHERIT not-null constraints on partitioned tables

  5. Better handle indirect constraint drops

  6. Don't try to assign smart names to constraints

  7. Fix restore of not-null constraints with inheritance

  8. ATTACH PARTITION: Don't match a PK with a UNIQUE constraint

  9. Fix propagating attnotnull in multiple inheritance

  10. Check stack depth in new recursive functions

  11. Move privilege check to the right place

  12. Update information_schema definition for not-null constraints

  13. Fix not-null constraint test

  14. Disallow changing NO INHERIT status of a not-null constraint

  15. Catalog not-null constraints

  16. parallel_schedule: add comment on event_trigger test dependency

  17. Revert "Catalog NOT NULL constraints" and fallout

  18. Adjust contrib/sepgsql regression test expected outputs.

  19. Fix table name clash in recently introduced test

  20. Catalog NOT NULL constraints

  21. Change the rules for inherited CHECK constraints to be essentially the same

On 2024-Feb-05, Alvaro Herrera wrote:

> So this regression test no longer fails:
> 
> create table cnn2_parted(a int primary key) partition by list (a);
> create table cnn2_part1(a int);
> alter table cnn2_parted attach partition cnn2_part1 for values in (1);

> Here, in the existing code the ALTER TABLE ATTACH fails with the error
> message that
>   ERROR:  primary key column "a" is not marked NOT NULL
> but with the patch, this no longer occurs.

I think this change is OK.  In the partition, the primary key is created
in the partition anyway (as expected) which marks the column as
attnotnull[*], and the table is scanned for presence of NULLs if there's
no not-null constraint, and not scanned if there's one.  (The actual
scan is inevitable anyway because we must check the partition
constraint).  This seems the behavior we want.

[*] This attnotnull constraint is lost if you DETACH the partition and
drop the primary key, which is also the behavior we want.


While playing with it I noticed this other behavior change from 16,

create table pa (a int primary key) partition by list (a);
create table pe (a int unique);
alter table pa attach partition pe for values in (1, null);

In 16, we get the error:
ERROR:  column "a" in child table must be marked NOT NULL
which is correct (because the PK requires not-null).  In master we just
let that through, but that seems to be a separate bug.

-- 
Álvaro Herrera        Breisgau, Deutschland  —  https://www.EnterpriseDB.com/
"Saca el libro que tu religión considere como el indicado para encontrar la
oración que traiga paz a tu alma. Luego rebootea el computador
y ve si funciona" (Carlos Duclós)