To investigate what status is the missing redo log is - select from v logfile shows which group and member is invalid 要检查丢失的重做日志处于什么状态select * from v $ logifle显示哪个组及哪个成员是无效的。
Now that you are confirmed that the lost redo file is an active redo log , shutdown the database - shutdown immediate 既然您确认丢失的重做文件是active重做日志，那么现在就可以关闭数据库shutdown immediate 。
Now that you are confirmed that the lost redo file is a current redo log , shutdown the database - shutdown immediate 既然您确认丢失的重做文件是current重做日志，那么现在就可以关闭数据库shutdown immediate 。
Now that you are confirmed that the lost redo file is an inactive redo log , shutdown the database - shutdown immediate 既然您已经确认丢失的重做文件是inactive重做日志，那么现在可以关闭数据库shutdown immediate 。
In circular logging , logs are used in a round robin manner much the same way as oracle uses redo logs in noarchivelog mode 在循环日志记录中，日志是以循环方式使用的，这非常像oracle在noarchivelog模式中使用重做日志。
As the name noarchivelog implies , there is no archiving of redo logs , and thus no rolling forward beyond the online redo logs 正如名称noarchivelog所暗示的那样，没有对重做日志进行归档，也就无法像联机重做日志那样支持前滚。
Now that you are confirmed that the lost redo file is an unarchived redo log archived no , shutdown the database - shutdown immediate 既然您确认丢失的重做文件是未归档重做日志（ archived = no ） ，那么现在就可以关闭数据库shutdown immediate 。
Since the redo log group is inactive and is archived , just clear the redo log - alter database clear logfile group n where n is the group of the lost redo log 由于重做日志组是不活动和归档的，所以只需清除重做日志即可alter database clear logfile group n （其中n是丢失的重做日志的组） 。
An incomplete recovery is a recovery that involves rolling forward the redo logs to bring the database to timestamp as far as the roll forward allows you with some lost of data 不完全恢复是这样的一种恢复，该恢复包括前滚重做日志，以便数据库恢复到某个时间戳，该前滚操作允许您丢失一些数据。
Redo logs are written in a round - robin manner ; therefore , before they are overwritten , the redo logs need to be archived either manually or automatically by kick - starting the arch process 重做日志是以循环的方式写入的；因此，在重写它们之前，需要通过启动arch进程来手动或自动对重做日志进行归档。
