Saturday, August 8, 2009

Redo log corruption and Recovery

You will see any of these errors, in case of redo log corruption

ORA-16038 log %s sequence# %s cannot be archived
ORA-367 checksum error in log file header
ORA-368 checksum error in redo log block
ORA-354 corrupt redo log block header
ORA-353 log corruption near block change time

Solution:- Try to clear the log file without shutdown the database.

You have to be careful when using 'alter database clear logfile', because the command erases all data in the logfile.

eg: alter database clear logfile group 1;
alter database clear unarchived logfile group 1;

Dropping/clearing the redo logs is not possible, if there are only two log groups and the corrupt logfile belongs to CURRENT/ACTIVE, it may be needed for instance recovery. You may receive ORA-1624 error.

If you receive ORA-1624 then you have to perform incomplete recovery stopping just before the redo log file which was corrupted.

Satishbabu Gunukula