Re: Prevent setting NO INHERIT on partitioned not-null constraints

Hi Andreas

On 20/05/2026 21:25, Andreas Karlsson wrote:
> Me and Joel found a bug when working on another patch. We noticed that
> you cannot create not-null constraints with NO INHEIRT set on
> partitioned tables, but you can actually set it later by using ALTER
> CONSTRAINT. This must be an oversight so I have attached a patch which
> adds a check to prevent this.
>
> The SQL below should give an error but does not:
>
> CREATE TABLE t (
>   a int,
>   CONSTRAINT a_is_not_null NOT NULL a
> ) PARTITION BY LIST (a);
>
> ALTER TABLE t ALTER CONSTRAINT a_is_not_null NO INHERIT;

+1 for the fix.

postgres=# CREATE TABLE t (
a int,
CONSTRAINT a_is_not_null NOT NULL a
) PARTITION BY LIST (a);
CREATE TABLE
postgres=# ALTER TABLE t ALTER CONSTRAINT a_is_not_null NO INHERIT;
ERROR: not-null constraint "a_is_not_null" on partitioned table "t"
cannot be NO INHERIT

The errcode is most likely wrong:

ERRCODE_WRONG_OBJECT_TYPE -> ERRCODE_FEATURE_NOT_SUPPORTED

At least it is inconsistent with an equivalent check in parse_utilcmd.c:

if (cxt->ispartitioned && constraint->is_no_inherit)
ereport(ERROR,
errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("not-null constraints on partitioned tables cannot be
NO INHERIT"));

Thanks!

Best, Jim