PostgreSQL查看系统视图的源码

[pg13@mambapg ~]$ psql -E
psql (13.2)
Type "help" for help.
postgres=# \l
********* QUERY **********
SELECT d.datname as "Name",
       pg_catalog.pg_get_userbyid(d.datdba) as "Owner",
       pg_catalog.pg_encoding_to_char(d.encoding) as "Encoding",
       d.datcollate as "Collate",
       d.datctype as "Ctype",
       pg_catalog.array_to_string(d.datacl, E'\n') AS "Access privileges"
FROM pg_catalog.pg_database d
ORDER BY 1;
**************************

                                 List of databases
   Name    |  Owner   | Encoding |  Collate   |   Ctype    |   Access privileges   
-----------+----------+----------+------------+------------+-----------------------
 pg13test1 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | 
 postgres  | postgres | UTF8     | en_US.utf8 | en_US.utf8 | 
 template0 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
           |          |          |            |            | postgres=CTc/postgres
 template1 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
           |          |          |            |            | postgres=CTc/postgres
(4 rows)
postgres-# \db+
********* QUERY **********
SELECT spcname AS "Name",
  pg_catalog.pg_get_userbyid(spcowner) AS "Owner",
  pg_catalog.pg_tablespace_location(oid) AS "Location",
  pg_catalog.array_to_string(spcacl, E'\n') AS "Access privileges",
  spcoptions AS "Options",
  pg_catalog.pg_size_pretty(pg_catalog.pg_tablespace_size(oid)) AS "Size",
  pg_catalog.shobj_description(oid, 'pg_tablespace') AS "Description"
FROM pg_catalog.pg_tablespace
ORDER BY 1;
**************************

                                  List of tablespaces
    Name    |  Owner   | Location | Access privileges | Options |  Size  | Description 
------------+----------+----------+-------------------+---------+--------+-------------
 pg_default | postgres |          |                   |         | 29 MB  | 
 pg_global  | postgres |          |                   |         | 575 kB | 
(2 rows)