Re: cataloguing NOT NULL constraints

On 2024-Feb-05, Alvaro Herrera wrote:

> Hmm, let me have a look, I can probably get this one fixed today before
> embarking on a larger fix elsewhere in the same feature.

You know what -- this missing CCI has a much more visible impact, which
is that the attnotnull marker that a primary key imposes on a partition
is propagated early. 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'm not sure that this behavior change is desirable ... I have vague
memories of people complaining that this sort of error was not very
welcome ... but on the other hand it seems now pretty clear that if it
*is* desirable, then its implementation is no good, because a single
added CCI breaks it.

I'm leaning towards accepting the behavior change, but I'd like to
investigate a little bit more first, but what do others think?

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