RMAN-06146：changes found for file number beyond offline SCN

错误原因：A CHANGE or REPORT command needs to compute the list of backups that are redundant and may be deleted. A backup was found for a file which is shown as offline in the target database control file, but the backup contains changes beyond the system change number(SCN) when the file went offline. This is most likely because the target database control file is not really current, but is a restored copy of an older control file.