这个命令是查询检测过期的备份（不是失效),检测到的文件取决于RMAN备份的冗余度，超出你的RMAN备份保留策略的备份，被视为过期的备份，也就是可以使用delete obsolete删除方式删除。 另外就是你的清除备份文件，是如何清除的！ 操作系统rm删除文件，还是通过rman命令

我在rman里用delete backup删掉了之前的备份文件，新生成的备份就有过期的了么😂

rman中看一下备份过期策略

RMAN> show all;

• obsolete backup

A backup that is not needed to satisfy the current backup retention policy. For example, if your retention policy dictates that you must maintain one backup of each data file, but you have two backups of data file 1, then the second backup of data file 1 is considered obsolete.