Re: list of extended statistics on psql

Hi Julien and Pavel!

>> How about using \dX rather than \dz?
>
> Thanks for your suggestion!
> I'll replace it if I got consensus. :-D

>> How about using \dX rather than \dz?
>
>Thanks for your suggestion!
>I'll replace it if I got consensus. :-D

I re-read a help message of \d* commands and realized it's better to
use "\dX".
There are already cases where the commands differ due to differences
in case, so I did the same way. Please find attached patch. :-D

For example:
==========
\da[S] [PATTERN] list aggregates
\dA[+] [PATTERN] list access methods
==========

Attached patch uses "\dX" instead of "\dz":
==========
\dx[+] [PATTERN] list extensions
\dX [PATTERN] list extended statistics
==========

Results of regress test of the feature are the following:
==========
-- check printing info about extended statistics
create table t1 (a int, b int);
create statistics stts_1 (dependencies) on a, b from t1;
create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
create table t2 (a int, b int, c int);
create statistics stts_4 on b, c from t2;
create table hoge (col1 int, col2 int, col3 int);
create statistics stts_hoge on col1, col2, col3 from hoge;

\dX
List of extended statistics
Schema | Table | Name | Columns | Ndistinct | Dependencies | MCV
--------+-------+-----------+------------------+-----------+--------------+-----
public | hoge | stts_hoge | col1, col2, col3 | t | t | t
public | t1 | stts_1 | a, b | f | t | f
public | t1 | stts_2 | a, b | t | t | f
public | t1 | stts_3 | a, b | t | t | t
public | t2 | stts_4 | b, c | t | t | t
(5 rows)

\dX stts_?
List of extended statistics
Schema | Table | Name | Columns | Ndistinct | Dependencies | MCV
--------+-------+--------+---------+-----------+--------------+-----
public | t1 | stts_1 | a, b | f | t | f
public | t1 | stts_2 | a, b | t | t | f
public | t1 | stts_3 | a, b | t | t | t
public | t2 | stts_4 | b, c | t | t | t
(4 rows)

\dX *hoge
List of extended statistics
Schema | Table | Name | Columns | Ndistinct | Dependencies | MCV
--------+-------+-----------+------------------+-----------+--------------+-----
public | hoge | stts_hoge | col1, col2, col3 | t | t | t
(1 row)
==========

Thanks,
Tatsuro Yamada