Oracle 19C Data Guard 基础运维 -02  S witchover s( 物理 )

原理：

https://docs.oracle.com/en/database/oracle/oracle-database/19/sbydb/data-guard-concepts-and-administration.pdf

Figure 9-1 Oracle Data Guard Configuration Before Switchover 

Figure 9-2 Standby Databases Before Switchover to the New Primary Database 

Figure 9-3 Oracle Data Guard Environment After Switchover 

Performing a Switchover to a Physical Standby Database

31.90 主库

SQL> select database_role,protection_level,protection_mode from v$database;  

DATABASE_ROLE  PROTECTION_LEVEL     PROTECTION_MODE

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

PRIMARY  MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE

31.100 备库

SQL> select database_role,protection_level,protection_mode from v$database;

DATABASE_ROLE  PROTECTION_LEVEL     PROTECTION_MODE

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

PHYSICAL STANDBY MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE

1. 验证目标备用数据库是否已准备好进行切换。

Verify that the target standby database is ready for switchover.

31.90 主库

SQL> select switchover_status from v$database;

SWITCHOVER_STATUS

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

TO STANDBY

或

SQL> alter database switchover to chendb verify;

Database altered

2. 在主数据库 CJCDB 上启动切换，方法是发出以下命令

Initiate the switchover on the primary database, CJCDB , by issuing the following

31.90 主库

SQL> alter database switchover to chendb;

Database altered.

3. 在新的主数据库 chendb 上发出以下 SQL 语句以打开它。

Issue the following SQL statement on the new primary database, CHICAGO , to open

it.

SQL> alter database open;  

4. 发出以下 SQL 语句以装载新的物理备用数据库 CJCDB ：

Issue the following SQL statement to mount the new physical standby database,

BOSTON :

SQL>startup mount;

或者，如果 CJCDB 是Oracle Active Data Guard物理备用数据库，则发出以下SQL语句以只读方式打开它：

Or, if BOSTON  is an Oracle Active Data Guard physical standby database, then

issue the following SQL statement to open it read only:

SQL> STARTUP;

5 . 在新的物理备用数据库 CJCDB 上启动Redo Apply 。例如：

Start Redo Apply on the new physical standby database. For example:

3.90 新备库

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;

SQL> select database_role,protection_level,protection_mode from v$database;

DATABASE_ROLE  PROTECTION_LEVEL     PROTECTION_MODE

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

PHYSICAL STANDBY MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE

3.100 新主库

SQL> select database_role,protection_level,protection_mode from v$database;

DATABASE_ROLE  PROTECTION_LEVEL     PROTECTION_MODE

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

PRIMARY  MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE

同步测试：

新主库chendb:

SQL> create table test2 as select level as id from dual connect by level <=3;

新备库cjcpdb:

SQL> select * from test2;

ID

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