ORA-16456: switchover to standby in progress or completed

SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;


SWITCHOVER_STATUS
--------------------
TO STANDBY


SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY;


Database altered.


SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY WITH SESSION SHUTDOWN;
ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY WITH SESSION SHUTDOWN
*
ERROR at line 1:
ORA-16456: switchover to standby in progress or completed

备库必须mount状态下,主库open状态

查看备库是

SQL> select open_mode from v$database;

OPEN_MODE
--------------------
READ ONLY WITH APPLY