Re: [HACKERS] 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



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