（1）查看主库状态

SQL> select db_unique_name,open_mode,database_role,switchover_status from v$database;

DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

--------------- -------------------- ---------------- --------------------

bhtcdbREAD WRITE PRIMARY TO STANDBY

（2）主库执行切换命令

SQL> alter database commit to switchover to physical standby with session shutdown wait;

Database altered.

（2）重启主库角色变为备库（mount状态）

SQL> startup mount;

ORACLE instance started.

Total System Global Area 1.3429E+10 bytes

Fixed Size 2265944 bytes

Variable Size 6878661800 bytes

Database Buffers 6543114240 bytes

Redo Buffers 4612096 bytes

Database mounted.

（4）查看主库状态

SQL> select db_unique_name,open_mode,database_role,switchover_status from v$database;

DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

--------------- -------------------- ---------------- --------------------

BhtcdbMOUNTED PHYSICAL STANDBYRECOVERY NEEDED

2.备库切换成主库（B机）

（1）查看备库状态

SQL> select db_unique_name,open_mode,database_role,switchover_status from v$database;

DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

--------------- -------------------- ---------------- --------------------

bhtcdgMOUNTED PHYSICAL STANDBYTO PRIMARY

（2）将备库切换成主库

SQL> alter database commit to switchover to primary with session shutdownwait;

Database altered.

（3）查看备库状态

SQL> select db_unique_name,open_mode,database_role,switchover_status from v$database;

DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

--------------- -------------------- ---------------- --------------------

bhtcdgMOUNTED PRIMARY NOT ALLOWED

（4）开启

SQL> alter database open;

Database altered.

SQL> select db_unique_name,open_mode,database_role,switchover_status from v$database;

DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE SWITCHOVER_STAT

--------------- ---------- ---------------- ---------------

bhtcdg READ WRITE PRIMARY RESOLVABLE GAP

3.打开数据库（A机）

SQL> alter database open read only;

4.应用日志（A机）

SQL> alter database recover managed standby database using current logfile disconnect from session;

3.验证数据

（1）在新主库创建用户（B机）

SQL> create user test1 identified by test1;

SQL> commit;

SQL> alter system switch logfile;

System altered.

（2）在新备库查看（A机）

SQL> select username from dba_users where username='TEST1';

USERNAME

------------------------------

TEST1

4.切换回最初的状态

(1) 新主库操作（B机）

SQL> alter database commit to switchover to physical standby with session shutdown;

Database altered.

SQL> startup mount;

ORACLE instance started.

Total System Global Area 1.3429E+10 bytes

Fixed Size 2265944 bytes

Variable Size 6878661800 bytes

Database Buffers 6543114240 bytes

Redo Buffers 4612096 bytes

Database mounted.

（2）新备库操作（A机）

SQL> alter database commit to switchover to primary with session shutdown;

Database altered.

SQL> alter database open;

Database altered.

SQL> select db_unique_name,open_mode,database_role,switchover_status from v$database;

DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

--------------- -------------------- ---------------- --------------------

bhtcdb READ WRITE PRIMARYRESOLVABLE GAP

（3）B机操作

SQL> select db_unique_name,open_mode,database_role,switchover_status from v$database;

DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

-------------------- -------------------- ---------------- --------------------

bhtcdgMOUNTED PHYSICAL STANDBY NOT ALLOWED

（4）打开备库开启实时同步

SQL> alter database open read only;

Database altered.

SQL> alter database recover managed standby database using current logfile disconnect;

Database altered.

SQL> select db_unique_name,open_mode,database_role,switchover_status from v$database;

DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE SWITCHOVER_STAT

--------------- ---------- ---------------- ---------------

bhtcdg READ ONLY PHYSICAL STANDBY NOT ALLOWED

WITH APPLY

（5）再次查看A机

SQL> select db_unique_name,open_mode,database_role,switchover_status from v$database;

DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

--------------- -------------------- ---------------- --------------------

bhtcdbREAD WRITE PRIMARY TO STANDBY

此时，已经切换回最初的状态

（6）备库查看日志应用情况

SQL> select sequence#,applied from v$archived_log;

SEQUENCE# APPLIED

---------- ---------

8 YES

7 YES

9 YES

10 YES

11 YES

12 YES

13 YES

13 YES

14 YES

14 YES

15 YES

SEQUENCE# APPLIED

---------- ---------

15 YES

16 YES

16 YES

17 YES

17 NO

18 YES

19 YES

20 YES

21 IN-MEMORY

---------- end ----------