Re: Psql patch to show access methods info

On Mon, Jul 22, 2019 at 6:29 AM Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
> On 2019-Jul-21, Alexander Korotkov wrote:
> > I've one note.  Behavior of "\dA" and "\dA pattern" look
> > counter-intuitive to me.  I would rather expect that "\dA pattern"
> > would just filter results of "\dA", but it displays different
> > information.  I suggest rename displaying access method properties
> > from "\dA pattern" to different.
>
> \dA+ maybe?  Then ...
>
> > And leave "\dA pattern" just filter results of "\dA".
>
> "\dA+ pattern" works intuitively, I think.

Sounds good for me.

We already have some functionality for \dA+.

# \dA+
                             List of access methods
  Name  | Type  |       Handler        |              Description
--------+-------+----------------------+----------------------------------------
 brin   | index | brinhandler          | block range index (BRIN) access method
 btree  | index | bthandler            | b-tree index access method
 gin    | index | ginhandler           | GIN index access method
 gist   | index | gisthandler          | GiST index access method
 hash   | index | hashhandler          | hash index access method
 heap   | table | heap_tableam_handler | heap table access method
 spgist | index | spghandler           | SP-GiST index access method
(7 rows)

What we need is that new \dA+ functionality cover existing one.  That
it, we should add Handler and Description column to the output.

# \dA+ *
                                     Index access method properties
   AM   | Ordering | Unique indexes | Multicol indexes | Exclusion
constraints | Include non-key columns
--------+----------+----------------+------------------+-----------------------+-------------------------
 brin   | no       | no             | yes              | no
        | no
 btree  | yes      | yes            | yes              | yes
        | yes
 gin    | no       | no             | yes              | no
        | no
 gist   | no       | no             | yes              | yes
        | yes
 hash   | no       | no             | no               | yes
        | no
 spgist | no       | no             | no               | yes
        | no
(6 rows)

                 Table access method properties
 Name | Type  |       Handler        |       Description
------+-------+----------------------+--------------------------
 heap | table | heap_tableam_handler | heap table access method
(1 row)




------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company