如何开启oracle闪回

首先查看是否开启闪回：SQL> select flashback_on from V$database;FLASHBACK_ON------------------NO二如果已经开启了闪回，无须执行下面的操作。cd /u01mkdir flashback(生成闪回目录)SQL> alter system set db_recovery_file_dest_size=30G scope=both;SQL> alter system set db_recovery_file_dest='/u01/flashback'  scope=both;SQL> shutdown immediateSQL> startup mountSQL> alter database archivelog;SQL> alter database flashback on;SQL> alter database open;三再进行确认：SQL> select flashback_on from V$database;FLASHBACK_ON------------------YES