在使用RMAN命令删除归档后，查询v$archived_log视图会发现name列为空了，但其他列的信息还保留，时间长了会留下很多过期的信息，
在使用RMAN命令删除归档后，查询v$archived_log视图会发现name列为空了，但其他列的信息还保留，时间长了会留下很多过期的信息，影响维护工作，需要将过期的信息删除。首先模拟下问题的出现过程：
出现这样的现象是因为使用RMAN命令在删除归档日志的时候不能够清楚控制文件中的内容，导致v$archived_log留下的过期的不完整信息。下面将归档信息进行清除：
但是这样是把所有的v$archive_log信息都清除了，，包括未过期的也会不清除。下面再将未过期的归档文件信息注册进来。
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