查看库大小

select 
  d."oid" as "对象ID", d."datname" as "实例名", d."owner" as "所属者",
  pg_catalog.pg_size_pretty(d."size") as "大小"
from (
  select 
    oid, datname, 
    pg_catalog.pg_get_userbyid(datdba) as "owner", 
    pg_catalog.pg_database_size(datname) as "size"
  from pg_catalog.pg_database
  where pg_catalog.has_database_privilege(datname, 'CONNECT')
  order by "size" desc
) as d

 执行结果：

查看表大小

select
	table_full_name as "表名",
	pg_catalog.pg_size_pretty(table_size) as "大小"
from (
	select
		table_schema || '.' || table_name as table_full_name,
		pg_catalog.pg_total_relation_size('"' || table_schema || '"."' || table_name || '"') as table_size
	from information_schema.tables
) as t
order by table_size desc, table_full_name

执行结果：