Oracle 12cR1 – How to Fix RMAN-11003, ORA-00354, ORA-00353 Corrupt Redo Log

If you don't have any backups. Well... You're just flat down.

Nothing to be done.

You might as well drop the entire database and recreate.

Reasons follow:

1.- Corrupt blocks can only be repaired by getting the original block from a full backup (at least of the datafile that has the corrupted blocks) and applying the archivelogs after the original block has been restored to the original location.

2.- No backups, No archivelogs and no exports means you lost your data. There is no way to get it back as you cannot find out the actual storage order of each row once it got corrupted.

3.- If the undo tablespace got corupted as well, you can't even recover a datafile/block because the RDBMS won't find the undo data needed to make it consistent. In the best of cases you could apply forward changes on the redo logs, but you couln't rollback unfinished transactions before the crash.

Next time, as soon as you have a running database, get it to work in archivelog mode, make a full back every once in a while and, to be on the safe side, export the most important data you have there..

Well, I guess the database is expendable since there is no proper backup. So just drop and recreate the database.

OK, seriously there are not many options left. Before you do anything shutdown the database and copy all files which belong to the database somewhere else! Because everything you do can make it worse.

Once you did that you have 2 options:

1. Open an Oracle Service Request. With their help try to restore the block with lots of tricks and magic.
2. Call the Oracle Consulting Team, they have unpublished/internal tools which might be helpful.

This database is not in archivelog mode so there is no option to restore the block from a backup. If you still have an rman backup of datafile 1 you might be able to restore this file and then open the database with _allow_resetlogs_corruption (Don't use this option on your own!). Because you cannot fully recover the block, you have to tell Oracle that you don't care that the datafile do not have the same SCN. See details here: https://practicalappsdba.wordpress.com/2008/04/01/how-to-recover-and-open-the-database-if-the-archive-log-required-for-recovery-is-missing/

If this is a block which contains standard objects you might be able to extract the block from a healthy database and inject it on this block.

Good luck!