Re: Things I don't like about \du's "Attributes" column

Nearby I dissed psql's \du command for its incoherent "Attributes"
column [1].  It's too late to think about changing that for v16,
but here's some things I think we should consider for v17:

* It seems weird that some attributes are described in the negative
("Cannot login", "No inheritance").  I realize that this corresponds
to the defaults, so that a user created by CREATE USER with no options
shows nothing in the Attributes column; but I wonder how much that's
worth.  As far as "Cannot login" goes, you could argue that the silent
default ought to be for the properties assigned by CREATE ROLE, since
the table describes itself as "List of roles".  I'm not dead set on
changing this, but it seems like a topic that deserves a fresh look.

* I do not like the display of rolconnlimit, ie "No connections" or
"%d connection(s)".  A person not paying close attention might think
that that means the number of *current* connections the user has.
A minimal fix could be to word it like "No connections allowed" or
"%d connection(s) allowed".  But see below.

* I do not like the display of rolvaliduntil, either.

I suggest that maybe it'd
be okay to change the pg_roles view along the lines of

-       '********'::text as rolpassword,
+       case when rolpassword is not null then '********'::text end as rolpassword,

Then we could fix \du to say nothing if rolpassword is null,
and when it isn't, print "Password valid until infinity" whenever
that is the case (ie, rolvaliduntil is null or infinity).

* On a purely presentation level, how did we possibly arrive
at the idea that the connection-limit and valid-until properties
deserve their own lines in the Attributes column while the other
properties are comma-separated?  That makes no sense whatsoever,
nor does it look nice in \x display format.

(b) move these two things into separate columns.

--DROP ROLE alice, bob, charlie, admin;

CREATE ROLE alice LOGIN SUPERUSER NOINHERIT PASSWORD 'alice' VALID UNTIL 'infinity' CONNECTION LIMIT 5;
CREATE ROLE bob LOGIN REPLICATION BYPASSRLS CREATEDB VALID UNTIL '2022-01-01';
CREATE ROLE charlie LOGIN CREATEROLE PASSWORD 'charlie' CONNECTION LIMIT 0;
CREATE ROLE admin;

COMMENT ON ROLE alice IS 'Superuser but with connection limit and with no inheritance';
COMMENT ON ROLE bob IS 'No password but with expire time';
COMMENT ON ROLE charlie IS 'No connections allowed';
COMMENT ON ROLE admin IS 'Group role without login';


Master.
=# \du                             List of roles Role name |                         Attributes                         
-----------+------------------------------------------------------------ admin     | Cannot login alice     | Superuser, No inheritance                                 +           | 5 connections                                             +           | Password valid until infinity bob       | Create DB, Replication, Bypass RLS                        +           | Password valid until 2022-01-01 00:00:00+03 charlie   | Create role                                               +           | No connections postgres  | Superuser, Create role, Create DB, Replication, Bypass RLS

=# \du+                                                            List of roles Role name |                         Attributes                         |                         Description                         
-----------+------------------------------------------------------------+------------------------------------------------------------- admin     | Cannot login                                               | Group role without login alice     | Superuser, No inheritance                                 +| Superuser but with connection limit and with no inheritance           | 5 connections                                             +|            | Password valid until infinity                              |  bob       | Create DB, Replication, Bypass RLS                        +| No password but with expire time           | Password valid until 2022-01-01 00:00:00+03                |  charlie   | Create role                                               +| No connections allowed           | No connections                                             |  postgres  | Superuser, Create role, Create DB, Replication, Bypass RLS | 


Patched.
=# \du                                    List of roles Role name | Can login? |                         Attributes                         
-----------+------------+------------------------------------------------------------ admin     | no         |  alice     | yes        | Superuser, No inheritance bob       | yes        | Create DB, Replication, Bypass RLS charlie   | yes        | Create role postgres  | yes        | Superuser, Create role, Create DB, Replication, Bypass RLS
(5 rows)

=# \du+                                                                                                List of roles Role name | Can login? |                         Attributes                         | Has password? |  Password expire time  | Max connections |                         Description                         
-----------+------------+------------------------------------------------------------+---------------+------------------------+-----------------+------------------------------------------------------------- admin     | no         |                                                            | no            |                        |              -1 | Group role without login alice     | yes        | Superuser, No inheritance                                  | yes           | infinity               |               5 | Superuser but with connection limit and with no inheritance bob       | yes        | Create DB, Replication, Bypass RLS                         | no            | 2022-01-01 00:00:00+03 |              -1 | No password but with expire time charlie   | yes        | Create role                                                | yes           |                        |               0 | No connections allowed postgres  | yes        | Superuser, Create role, Create DB, Replication, Bypass RLS | yes           |                        |              -1 | 
(5 rows)

-- 
Pavel Luzanov
Postgres Professional: https://postgrespro.com