I created a POC patch that allows showing a list of extended statistics by "\dz" command on psql. I believe this feature helps DBA and users who would like to know all extended statistics easily. :-D
I have not a strong opinion to assign "\dz". I prefer "\dx" or "\de*" than "\dz" but they were already assigned. Therefore I used "\dz" instead of them.
Please find the attached patch. Any comments are welcome!
For Example: ======================= CREATE TABLE t1 (a INT, b INT); CREATE STATISTICS stts1 (dependencies) ON a, b FROM t1; CREATE STATISTICS stts2 (dependencies, ndistinct) ON a, b FROM t1; CREATE STATISTICS stts3 (dependencies, ndistinct, mcv) ON a, b FROM t1; ANALYZE t1;
CREATE TABLE t2 (a INT, b INT, c INT); CREATE STATISTICS stts4 ON b, c FROM t2; ANALYZE t2;
postgres=# \dz List of extended statistics Schema | Table | Name | Columns | Ndistinct | Dependencies | MCV --------+-------+-------+---------+-----------+--------------+----- public | t1 | stts1 | a, b | f | t | f public | t1 | stts2 | a, b | t | t | f public | t1 | stts3 | a, b | t | t | t public | t2 | stts4 | b, c | t | t | t (4 rows)
postgres=# \? ... \dy [PATTERN] list event triggers \dz [PATTERN] list extended statistics \l[+] [PATTERN] list databases ... =======================
For now, I haven't written a document and regression test for that. I'll create it later.
