Re: Partitions: \d vs \d+

On 2017/09/28 22:19, Maksim Milyutin wrote:
> I also noticed ambiguity in printing "No partition constraint" in
> non-verbose mode and "Partition constraint:..." in verbose one for
> partition tables regardless of the type of partition.
> Attached small patch removes any output about partition constraint in
> non-verbose mode.

Patch looks good.

So, we should be looking at partconstraintdef only when verbose is true,
because that's only when we set it to a valid value. Now, if
partconstraintdef is NULL even after verbose is true, that means backend
returned that there exists no constraint for that partition, which I
thought would be true for a default partition (because the commit that
introduced default partitions also introduced "No partition constraint"),
but it's really not.

For example, \d and \d+ show contradictory outputs for a default partition.

create table p (a int) partition by list (a);
create table p1 partition of p for values in (1);
create table pd partition of p default;

\d pd
Table "public.pd"
Column | Type | Collation | Nullable | Default
--------+---------+-----------+----------+---------
a | integer | | |
Partition of: p DEFAULT
No partition constraint

\d+ pd
Table "public.pd"
Column | Type | Collation | Nullable | Default | Storage | Stats
target | Description
--------+---------+-----------+----------+---------+---------+--------------+-------------
a | integer | | | | plain | |
Partition of: p DEFAULT
Partition constraint: (NOT ((a IS NOT NULL) AND (a = ANY (ARRAY[1]))))

Perhaps, there is no case when "No partition constraint" should be output,
but I may be missing something.

Thanks,
Amit