select pg_size_pretty(pg_database_size('lrisk')); --查詢數據庫剩余空間
select pg_database.datname,pg_size_pretty(pg_database_size('lrisk')) AS size
from pg_database;
select * from pg_database;
SELECT relname, relpages FROM pg_class ORDER BY relpages DESC; --查詢數據庫對象占用空間從大到小排序