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: Matthias van de Meent <boekewurm+postgres@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Pg Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-09-20T10:56:19Z
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 2022-Sep-19, Matthias van de Meent wrote:

> I'm not sure on the 'good' part of this alternative, but we could go
> with a single row-based IS NOT NULL to reduce such clutter, utilizing
> the `ROW() IS NOT NULL` requirement of a row only matching IS NOT NULL
> when all attributes are also IS NOT NULL:
> 
>     Check constraints:
>         "tab_notnull_check" CHECK (ROW(a, b, c, d, e) IS NOT NULL)

There's no way to mark this NOT VALID individually or validate it
afterwards, though.

> But the performance of repeated row-casting would probably not be as
> good as our current NULL checks

The NULL checks would still be mostly done by the attnotnull checks
internally, so there shouldn't be too much of a difference.

.. though I'm now wondering if there's additional overhead from checking
the constraint twice on each row: first the attnotnull bit, then the
CHECK itself.  Hmm.  That's probably quite bad.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/