在设置为noarchivelog模式时，要先把闪回功能关闭

    今天在数据库在切换到noarchivelog模式时，出现了错误，具体操做如下：

  

SQL> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> startup mount

ORACLE instance started.



Total System Global Area 849530880 bytes

Fixed Size 1339824 bytes

Variable Size 641732176 bytes

Database Buffers 201326592 bytes

Redo Buffers 5132288 bytes

Database mounted.

SQL> alter database noarchivelog;

alter database noarchivelog

*

ERROR at line 1:

ORA-38774: cannot disable media recovery - flashback database is enabled





SQL> alter database flashback off;



Database altered.



SQL> alter database noarchivelog;



Database altered.



SQL> alter database open;



Database altered.



SQL>

为什么要先关掉flashback 呢，因为flashback是建立在archivelog上的，所以在关闭archivelog时，要先关闭flashback