[oracle11g]system用户没有权限关闭数据库

1、su - oracle 切换oracle用户环境
2、./sqlplus 登录system用户
3、shutdown immediate 关闭数据库，报错没有权限

SQL> shutdown immediate;
ORA-01031: insufficient privileges
SQL> conn /as sysdba
Connected.
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area 5344731136 bytes
Fixed Size                  2213136 bytes
Variable Size            4294970096 bytes
Database Buffers         1006632960 bytes
Redo Buffers               40914944 bytes
Database mounted.
Database opened.

[忘记system密码]https://blog.csdn.net/Alien_come/article/details/108993712

system为什么关闭不了？https://blog.csdn.net/lantian000/article/details/106036403