Tuesday 17 September 2013

Online Redo corruption

Hi,

One of my development db was affected because of Online Redo corruption.

Since it is non - critical db I have applied this solution and got my db back.

If you face Online Redo corruption, Please raise SR with oracle before trying this soln.


DB would go upto Mount Stage.

You can fing LGWR error in alertlog file.

Soln.

Create a pfile

>create pfile from spfile;

In Pfile add the undocumented oracle parameter

_allow_resetlogs_corruption=true

then start the db using the edited Pfile.

Now It needs an fake recovery..

So

>startup Mount;

>recover database;

>alter database open resetlogs;


then give checpoint

>alter system checkpoint

>alter system switch logfile

recreate the corruputed redolog file by dropping the existing one.

Remove that undocumented parameter from pfile.
 
Then Found the database is not consistent.. and instance was terminated automatically..
 
In alertlog
 
Found ORA-600
 
The issue was because of some uncommited transactions (corruption) in the undo tablespace
 
So, created New undo tablespace and then assigned undo_tablespace into new undo tablespace, restarted the instance.
 
Finally Issue got cleared..
 
Experts comments welcome...