Hi All I have a few basic questions:
1] How Oracle knows that media recovery is needed during STARTUP ? Is it based on mismatch of SCN or ckpt# or anything else ? I understand, if the datafile is missing then in Mount stage it throws error. Is there any other situation where it throws media recovery reqd. And, can a single block corruption be the reason enough for media recovery- error message during Startup. I believe, block corruption in a non-system datafile does not shutdown the instance and it gives error for the session accessing the block. So during next instance startup will this corrupted block cause any problem? 2] How oracle comes to know that instance recovery is needed during startup. 3] say we have a backup of the controlfile and we are using it as we lost all the present control files. In the backup controlfile in user_dump_dest I see All the datafiles (both SYSTEM and NON-SYSTEM) are listed in the 'create controlfile ' cmd. Then after creating the new controlfile in NO-mount stage , how can we associate the non system tablespace names with the existing OK datafiles ? Please help me clear my doubts? Thanks a Lot Regards B S Pradhan
