使用flashback database 特性将dataguard 的standby 库激活为rea

可以利用10g的flashback特性来实现激活为standby库为read write状态，standby库处于read write状态时可以在standby库上进行一些不能在主库上进行的测试工作，在完成之后可以将read write状态stnadby库flashback到原来的recover mount状态,下图为操作原理过程：

下为实验过程：

一．从库：

1．?设置flashback区域：

要使用这个特性就必须在standby库中设置flashback

在我的库中：

SQL> show parameter DB_RECOVERY_FILE_DEST

NAME????????????????????????????????TYPE???????VALUE

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

db_recovery_file_dest???????????????string?????/dg_flashback

db_recovery_file_dest_size??????????big integer??980M

?

2．?Standby库取消redo日志的应用并创建一个数据库的flashback?点

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;

Database altered.

?

SQL> CREATE RESTORE POINT before_application_test GUARANTEE FLASHBACK

?2?DATABASE;

Restore point created.

?

二?主库

1．归档当前的日志文件，可从库确认这个flackback的SCN：

SQL> ALTER SYSTEM ARCHIVE LOG CURRENT;

System altered.

2．停止主库的日志传到从库：

SQL> ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_2=DEFER;

System altered.

?

三．激活为standby库为read write状态

1．激活为standby库

SQL> ALTER DATABASE ACTIVATE STANDBY DATABASE;

Database altered.

?

2，如果standb处于readonly状态时，强制重启到mount

SQL> STARTUPMOUNTFORCE;

ORA-32004: obsolete and/or deprecated parameter(s) specified

ORACLE instance started.

Total System Global Area?218103808 bytes

Fixed Size?????????????????1260984 bytes

Variable Size?????????????83886664 bytes

Database Buffers?????????130023424 bytes

Redo Buffers???????????????2932736 bytes

Database mounted.

?

3.将standb改成?performance保护模式，并打开数据到read write状态，主库并不受standby库的影响，可以按正常的方式进行操作：

SQL> ALTER DATABASE SET STANDBY DATABASE TO MAXIMIZE PERFORMANCE;

Database altered.

?

SQL> ALTER DATABASE OPEN;

?

Database altered.

SQL> select open_mode from v$database;

?

OPEN_MODE

----------

READ WRITE

这时可以进行各种test工作：我在主库建表t_flash,standby库建了一张f_t表：可以在flashback之后看他是否还存在：

?

在主库建：

SQL> create table t_flash(name char(30));

Table created.

SQL> insert into?t_flash values('just a test');

1 row created.

?

SQL> commit;

Commit complete.

从库建表f_t：

SQL> create table f_t( a int);

?

Table created.

?

SQL> insert into f_t values(34);

?

1 row created.

?

SQL> commit;

?

Commit complete.

?

?

三．将standby库flashback到before_application_tes时的SCN并重新置为physical standby role

1从库：

SQL> STARTUP MOUNT FORCE;

ORA-32004: obsolete and/or deprecated parameter(s) specified

ORACLE instance started.

?

Total System Global Area?218103808 bytes

Fixed Size?????????????????1260984 bytes

Variable Size?????????????92275272 bytes

Database Buffers?????????121634816 bytes

Redo Buffers???????????????2932736 bytes

Database mounted.

SQL> FLASHBACK DATABASE TO RESTORE POINT before_application_test;

?

Flashback complete.

?

SQL> ALTER DATABASE CONVERT TO PHYSICAL STANDBY;

?

Database altered.

?

SQL> STARTUP MOUNT FORCE;

ORA-32004: obsolete and/or deprecated parameter(s) specified

ORACLE instance started.

?

Total System Global Area?218103808 bytes

Fixed Size?????????????????1260984 bytes

Variable Size????????????100663880 bytes

Database Buffers?????????113246208 bytes

Redo Buffers???????????????2932736 bytes

Database mounted.

SQL> select * from v$archive_gap;??

?

no rows selected

?

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT;

?

Database altered.

?

?

2．主库

?SQL> ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_2=ENABLE;

?

四．检查在standby库被激活时的分别在pirmary,standby库上建的表，此时在standby库中是否存在：

SQL> alter database recover managed standby database cancel;

Database altered.

?

SQL> alter database open read only;

?

Database altered.

---从库的表已经不存在：

SQL> select * from f_t;

select * from f_t

?????????????*

ERROR at line 1:

ORA-00942: table or view does not exist

?

主库的表已经通过archivelog的apply在standby库中已经可以查询到了：

SQL> select * from t_flash;

?

NAME

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

just a test