这篇文章讨论将Standby数据库临时转换为主数据库，原本的主数据库不发生变化。

1.在主数据库延迟向Standby数据库传送日志。

SQL> alter system set log_archive_dest_state_2=defer;

System altered.

2.启用Standby数据库flashback database特性。

SQL> startup mount

ORACLE instance started.

Total System Global Area 784998400 bytes

Fixed Size 2230600 bytes

Variable Size 281020088 bytes

Database Buffers 494927872 bytes

Redo Buffers 6819840 bytes

Database mounted.

SQL> alter database flashback on;

Database altered.

SQL> show parameter recover

NAME TYPE VALUE

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

db_recovery_file_dest string +DGFRA

db_recovery_file_dest_size big integer 10G

db_unrecoverable_scn_tracking boolean TRUE

recovery_parallelism integer 0

3.在备用数据库取消FAL配置。

SQL> show parameter fal

NAME TYPE VALUE

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

fal_client string

fal_server string ractest

SQL> alter system set fal_server='';

System altered.

4.创建还原点。

SQL> select open_mode from v$database;

OPEN_MODE

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

MOUNTED

SQL>

SQL> create restore point Before_App_Test guarantee flashback database;

Restore point created.

5.激活Standby数据库。

SQL> alter database activate standby database;

Database altered.

SQL> alter database open;

Database altered.

SQL> select open_mode from v$database;

OPEN_MODE

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

READ WRITE

6.模拟测试数据。

SQL> create table test199(id number primary key);

Table created.

SQL> begin

2 for i in 1..1000 loop

3 insert into test199 values(i);

4 end loop;

5 end;

6 /

PL/SQL procedure successfully completed.

SQL> commit;

Commit complete.

SQL> select count(1) from test199;

COUNT(1)

----------

1000

7.将Standby数据库利用flashback database特性恢复到还原点。

SQL> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> startup mount

ORACLE instance started.

Total System Global Area 784998400 bytes

Fixed Size 2230600 bytes

Variable Size 281020088 bytes

Database Buffers 494927872 bytes

Redo Buffers 6819840 bytes

Database mounted.

SQL> flashback database to restore point before_app_test;

Flashback complete.

8.将主数据库转换为Standby数据库。

SQL> alter database convert to physical standby;

Database altered.

SQL> alter database open;

alter database open

*

ERROR at line 1:

ORA-01507: database not mounted

SQL> select status from v$instance;

STATUS

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

STARTED

SQL> alter database mount;

alter database mount

*

ERROR at line 1:

ORA-00750: database has been previously mounted and dismounted

SQL> shutdown immediate

ORA-01507: database not mounted

ORACLE instance shut down.

SQL> startup mount

ORACLE instance started.

Total System Global Area 784998400 bytes

Fixed Size 2230600 bytes

Variable Size 281020088 bytes

Database Buffers 494927872 bytes

Redo Buffers 6819840 bytes

Database mounted.

SQL> alter database open;

Database altered.

SQL> select name,open_mode from v$database;

NAME OPEN_MODE

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

RACTEST READ ONLY

SQL> select count(1) from test199;

select count(1) from test199

*

ERROR at line 1:

ORA-00942: table or view does not exist

9.恢复主数据库向Standby数据库的日志传递。

SQL> alter system set log_archive_dest_state_2=enable;

System altered.

SQL> alter system switch logfile;

System altered.

SQL> select thread#,dest_id,max(sequence#) from v$archived_log where resetlogs_id=786500749 group by thread#,dest_id;

THREAD# DEST_ID MAX(SEQUENCE#)

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

2 1 71

1 2 102

1 1 102

2 2 70

SQL> select thread#,dest_id,max(sequence#) from v$archived_log where resetlogs_id=786500749 group by thread#,dest_id;

THREAD# DEST_ID MAX(SEQUENCE#)

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

2 1 72

1 2 102

1 1 102

2 2 72

10.恢复Standby数据库的FAL配置。

SQL> alter system set fal_server='ractest';

System altered.

参考文章：
http://blog.csdn.net/henrybai/article/details/3020068

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ITPub博客

将Standby数据库临时转换为主数据库用于测试

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