為特定用戶組設置參數：數據庫里面的所有用戶：alter database db_name set param=val;為某個用戶：alter role role_name set param=val;為特定用戶連接到特定數據庫：alter role role_name in database db_name set param=val;簡單示例：postgres=# alter database postgres set work_mem='123MB';ALTER DATABASE[postgres@pg datan]$ psql -h /home/postgres/psql (9.6.1)Type "help" for help.postgres=# show work_mem; work_mem---------- 123MB(1 row)