1.创建目录

mkdir /u01/app/oracle/flash

2.配置FRA

alter system set db_recovery_file_dest_size=15G;

alter system set db_recovery_file_dest='/u01/app/oracle/flash';

3.设置闪回参数--确保可以闪回48h内的数据库

 alter system set db_flashback_retention_target=2880;

4.开闪回

alter database flashback on;

实践：闪回部分数据

1.解锁hr账户连接数据库

alter user hr identified by hr account unlock;

2.运行脚本

在这个脚本中，有两个事务，我们尝试保留insert的事务，回滚update的事务。

conn hr/hr@prod4
insert into departments values(290,'Poduct Sales',114,1800);
insert into departments values(300,'Busses Sales',203,1700);
insert into departments values(280,'Mac Sales',205,1700);
commit;
--update
update departments set department_id=310 where department_id=300;
update departments set department_name='Iphone sales' where department_id=280;
commit;

3.闪回版本查询

SELECT versions_xid XID, versions_startscn START_SCN,
versions_endscn END_SCN, versions_operation OPERATION,
department_id,department_name
FROM departments
VERSIONS BETWEEN SCN MINVALUE AND MAXVALUE;

alter table departments enable row movement;

flashback table departments to scn 2148345;

5.校验表，发现表已经闪回到想要的时间点