1.确认当前模式

　　SYS AS SYSDBA on 29-MAR-05 >select flashback_on from v$database;

　　FLA

　　---

　　NO

　　2.检查/修改恢复区设置

　　SYS AS SYSDBA on 29-MAR-05 >show parameter db_recovery_file_dest

　　NAME

　　TYPE

　　VALUE

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

　　db_recovery_file_dest

　　string /data5/flash_recovery_area

　　db_recovery_file_dest_size

　　big integer 10G

　　

　　3.检查/修改闪回时间设置

　　SYS AS SYSDBA on 29-MAR-05 >show parameter db_flashback_retention_target

　　NAME

　　TYPE

　　VALUE

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

　　db_flashback_retention_target

　　integer 60

　　SYS AS SYSDBA on 29-MAR-05 >alter system set db_flashback_retention_target=1440;

　　System altered.

　　4.重新启动数据库到Mount状态

　　启动flashback database选项。

　　SYS AS SYSDBA on 29-MAR-05 >shutdown immediate;

　　Database closed.

　　Database dismounted.

　　ORACLE instance shut down.

　　SYS AS SYSDBA on 29-MAR-05 >startup mount;

　　ORACLE instance started.

　　Total System Global Area 314572800 bytes

　　Fixed Size

　　1301704 bytes

　　Variable Size

　　261890872 bytes

　　Database Buffers

　　50331648 bytes

　　Redo Buffers

　　1048576 bytes

　　Database mounted.

　　SYS AS SYSDBA on 29-MAR-05 >alter database flashback on;

　　Database altered.

　　SYS AS SYSDBA on 29-MAR-05 >alter database open;

　　Database altered.