--开启闪回数据库

--1.1数据库需要运行在归档模式

sys@TESTDB11>archive log  list;

Database log mode              Archive Mode

Automatic archival             Enabled

Archive destination            /archive2

Oldest online log sequence     1

Next log sequence to archive   2

Current log sequence           2

--1.2开快速恢复区（就是2个初始化参数）

sys@TESTDB11>show parameter db_recovery_file

NAME                                 TYPE        VALUE

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

db_recovery_file_dest                string      /u01/app/oracle/fast_recovery_

                                                 area

db_recovery_file_dest_size           big integer 4122M

--1.3 开启闪回归档

sys@TESTDB11>shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

sys@TESTDB11>startup mount

ORACLE instance started.

Total System Global Area  855982080 bytes

Fixed Size                  2230792 bytes

Variable Size             641730040 bytes

Database Buffers          209715200 bytes

Redo Buffers                2306048 bytes

Database mounted.

sys@TESTDB11>select flashback_on from v$database;

FLASHBACK_ON

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

NO

sys@TESTDB11>alter database flashback on;

Database altered.

sys@TESTDB11>select flashback_on from v$database;

FLASHBACK_ON

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

YES

sys@TESTDB11>alter database open;

Database altered.