从9i以后，oracle dataguard 备库一般都不需要手工处理丢失的日志，FAL自动会帮我们处理，下面通过个案例来讲下手工处理丢失的日志的方法:
1.在备库查询有哪些日志丢失，没应用到备库
SQL> select * from V$ARCHIVE_GAP;
THREAD# LOW_SEQUENCE# HIGH_SEQUENCE#
---------- ------------- --------------
1 9873 9876
我们可以看到9873到9876这四个归档日志丢失，
2.我们在主库找到这四个归档日志传送到备库归档目录下；
3.备库注册
alter database register logfile '/oracle/app/oracle/archive/1_9873_629923600.arc'; system alerted alter database register logfile '/oracle/app/oracle/archive/1_9874_629923600.arc'; system alerted alter database register logfile '/oracle/app/oracle/archive/1_9875_629923600.arc'; system alerted alter database register logfile '/oracle/app/oracle/archive/1_9876_629923600.arc'; system alerted
4.检查数据库日志看是否应用
Thu Apr 8 15:55:17 2010 Media Recovery Log /oracle/app/oracle/archive/1_9873_629923600.arc Media Recovery Log /oracle/app/oracle/archive/1_9874_629923600.arc Media Recovery Log /oracle/app/oracle/archive/1_9875_629923600.arc Media Recovery Log /oracle/app/oracle/archive/1_9876_629923600.arc
或者查询视图
v$archived_log的applied字段
5、检查备库是否还有日志GAP
SQL> select * from V$ARCHIVE_GAP;
出现没有行选择，则表示不存在归档日志丢失问题。