--执行次数多的SQL
select sql_text,executions from (
select sql_text,executions from v$sqlarea order by executions desc
) where rownum<81;
--读硬盘多的SQL
select sql_text,disk_reads from(
select sql_text,disk_reads from v$sqlarea order by disk_reads desc
) where rownum<21;
--.查看所有用户：
select * from dba_users;
select * from all_users;
select * from user_users;
--查看用户或角色系统权限(直接赋值给用户或角色的系统权限)：
select * from dba_sys_privs;
select * from user_sys_privs;
--查看角色(只能查看登陆用户拥有的角色)所包含的权限
select * from role_sys_privs;
--查看用户对象权限
select * from dba_tab_privs;
select * from all_tab_privs;
select * from user_tab_privs;
--查看所有角色
select * from dba_roles;
--查看用户或角色所拥有的角色
select * from dba_role_privs;
select * from user_role_privs;
--查看哪些用户有sysdba或sysoper系统权限(查询时需要相应权限)
select * from V$PWFILE_USERS
SELECT name,spare4 FROM SYS.USER$ WHERE password is not null;