Data Guard物理备库的主备切换
1.查看状态
主库：
SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;
SWITCHOVER_STATUS
------------------------------------------------------------
TO STANDBY //可以转换成备库
备库：
SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;
SWITCHOVER_STATUS
------------------------------------------------------------
NOT ALLOWED
2.主切备
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY;
数据库已更改。
Total System Global Area 751595520 bytes
Fixed Size 2292912 bytes
Variable Size 557843280 bytes
Database Buffers 188743680 bytes
Redo Buffers 2715648 bytes
SQL> alter database mount standby database;
数据库已更改。
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;
数据库已更改。
3.备切主
SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;
SWITCHOVER_STATUS
------------------------------------------------------------
TO PRIMARY
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;
数据库已更改。
SQL> select status from v$instance;
STATUS
------------------------------------
MOUNTED
SQL> alter database open;
数据库已更改。
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