fuzzy in datafile header

datafile was restored from a conventional (non-RMAN) backup that was taken while the datafile was NOT in backup mode. (If this were the case, it would not be possible to do any type of recovery, complete or incomplete, due to ORA-1547 and ORA-1194 (Recover succeeded but open resetlogs will get error below, file needs more recovery to be consistent.))

原文地址： http://orafaq.com/maillist/oracle-l/2006/06/06/0311.htm

可以产生这种情况的， 在A 库正常运行过程中，直接cp 拷贝就会出现这种情况。  因为这个数据库没有backup mode。(像正常情况，数据文件没有丢失，不需要restore，但还是需要recover， 这样估计也没有backup mode， 但可以恢复，所以前面所说有不合理之处，还望更正）。 当事实上，确实是不能恢复，就如同 文章所说：
If this were the case, it would not be possible to do any type of recovery, complete or incomplete, due to ORA-1547 and ORA-1194 (Recover succeeded but open resetlogs will get error below, file needs more recovery to be consistent.))


oracle 为什么要由这种措施？  其实完全可以遍历整个block，找到最早的scn， 然后恢复啊？ 除非重新从主库备份这个数据文件，有没有其他措施？

> 事实上，确实是不能恢复

Are you saying even if you guarantee there's no change after the latest checkpoint and you do file copy (when the database was not in backup mode) and you still can't recover the database with the "直接cp 拷贝" datafiles? Can you try it? Make sure v$datafile_header.fuzzy is 'YES', and there's no DB activity, no job. Alter system checkpoint. Copy the file. Then copy the copied file back to overwrite the original file. Is that a good test to answer your question?

Yong Huang