No result when selecting attstattarget from pg_attribute

Hello %

I was following the create statistics example from the doc

https://www.postgresql.org/docs/11/sql-createstatistics.html

and wondered why I don't see any results when selecting attstattarget from pg_attribute.

Version: PostgreSQL 11.5

(klb@[local]:55000)[knowledgebase]> CREATE TABLE t1 (

>     a   int,

>     b   int

> );

CREATE TABLE

(klb@[local]:55000)[knowledgebase]> INSERT INTO t1 SELECT i/100, i/500

>                  FROM generate_series(1,1000000) s(i);

INSERT 0 1000000

(klb@[local]:55000)[knowledgebase]> ANALYZE t1;

ANALYZE

-- No custom statistics here, which is OK

(klb@[local]:55000)[knowledgebase]> select attrelid::regclass as name, attname, attstattarget from pg_attribute where attname in ('a','b');

name | attname | attstattarget

------+---------+---------------

t1   | a       |            -1

t1   | b       |            -1

(2 rows)

(klb@[local]:55000)[knowledgebase]> SELECT attrelid::regclass, attname, attstattarget FROM pg_attribute WHERE attstattarget > 0 order by attstattarget desc;

attrelid | attname | attstattarget

----------+---------+---------------

(0 rows)

-- Now I create the custom statistics, however, attstattarget is still -1

(klb@[local]:55000)[knowledgebase]> CREATE STATISTICS s1 (dependencies) ON a, b FROM t1;

CREATE STATISTICS

(klb@[local]:55000)[knowledgebase]> select attrelid::regclass as name, attname, attstattarget from pg_attribute where attname in ('a','b');

name | attname | attstattarget

------+---------+---------------

t1   | a       |            -1

t1   | b       |            -1

(2 rows)

Am I looking at the wrong view? I am planning to do some upgrades to 12.x, and therefore, I created this little test case

to make sure that I don't forget to set custom statistics on the new version, if there are any.

Cheers

William