SELECT pg_size_pretty(pg_database_size('name of database'));

会给你一个特定数据库的总大小，但我不认为你可以做所有的数据库在一个服务器。

然而你可以这样做…

DO
$$
DECLARE
r   RECORD;
db_size TEXT;
BEGIN
FOR r in
SELECT datname FROM pg_database
WHERE datistemplate = false
LOOP
db_size:= (SELECT pg_size_pretty(pg_database_size(r.datname)));

RAISE NOTICE 'Database:% , Size:%', r.datname , db_size;

END LOOP;
END;
$$

-- Database Size
SELECT pg_size_pretty(pg_database_size('Database Name'));
-- Table Size
SELECT pg_size_pretty(pg_relation_size('table_name'));

是的，在Postgres中有一个命令可以查找数据库的大小。是这样的:

SELECT pg_database.datname as "database_name", pg_size_pretty(pg_database_size(pg_database.datname)) AS size_in_mb FROM pg_database ORDER by size_in_mb DESC;

du -k /var/lib/postgresql/ |sort -n |tail

您可以使用下面的查询来查找PostgreSQL所有数据库的大小。

参考资料来自这个博客。

SELECT 
    datname AS DatabaseName
    ,pg_catalog.pg_get_userbyid(datdba) AS OwnerName
    ,CASE 
        WHEN pg_catalog.has_database_privilege(datname, 'CONNECT')
        THEN pg_catalog.pg_size_pretty(pg_catalog.pg_database_size(datname))
        ELSE 'No Access For You'
    END AS DatabaseSize
FROM pg_catalog.pg_database
ORDER BY 
    CASE 
        WHEN pg_catalog.has_database_privilege(datname, 'CONNECT')
        THEN pg_catalog.pg_database_size(datname)
        ELSE NULL
    END DESC;

根据@Hendy Irawan的回答

显示数据库大小:

\l+

e.g.

=> \l+
 berbatik_prd_commerce    | berbatik_prd     | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                       | 19 MB   | pg_default | 
 berbatik_stg_commerce    | berbatik_stg     | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                       | 8633 kB | pg_default | 
 bursasajadah_prd         | bursasajadah_prd | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                       | 1122 MB | pg_default | 

显示表大小:

\d+

e.g.

=> \d+
 public | tuneeca_prd | table | tomcat | 8192 bytes | 
 public | tuneeca_stg | table | tomcat | 1464 kB    | 

只适用于psql。