Re: Redo log file damaged. Help!

Your online redo log file is most definately corrupt, the question you need to answer is, how much data was in the redolog at the time of the corruption?
By this I mean, did Oracle crash or did you manage to initially shut the database down using shutdown as opposed to shutdown immediate/abort? mount the database
issue an alter database recover auto
(Oracle will then attempt to get any archived information missing back into the database and attempt to get any usuable info from the online redo log files) You dont need to worry about giving it a point and time.. ie as some as the other suggestions have told you to recover just up to the point and time before the corruption. Please note.. once you issue the alter database resetlogs command if you had any backups **ALL** archived logs become INVALID and cant be used anyways.
The good news is.. you didnt loose your entire database and if none of your tablespaces were in backup mode (and depending upon the type of database you have in operation).. you really havent lost any data. Honestly.. this error has NOTHING to do with control files or any other database structures other than the online redo files.. and if you experienced a crash right before this problem, there isnt anything wrong with the datafile "logfile1.ora" either.. so it wont need to be replaced. If Oracle crashed hard enough, the online redo log file could have easily been corrupted.
So remember.. the only information you might have lost would have been transactions current in memory not yet written out to the associated tablespaces.. everything else is still there. Implement a proper backup/recovery scheme .. such as mirroring you control files, multiplexing your online redo logs, making sure your database is in archive mode, etc.

I hope this helps!! (this just happened to a machine I was asked to fixed)

Shelley LaPorte
Mgr DBA Group
Senior DBA
International Telcom LTD.

Danil wrote:

> Hello, all. Please help!
>
> When I try to open database, I get error messages:
> ORA-0368 Checksum error in redo log block
> ORA-0353 Log corruption near block 316 change 248148
> ORA-0312 Online log 2 thread 1 : 'logfile1.ora'
>
> I think that is due to redo log file damage.
> How to recover redo log file?
> Or how to recover information in database?
> ( There is no backup copy of database :-(( )
>
> Danil Krasnov.
> If possible, copy answer to email: danil_at_maginfo.net
>
> Thanks in advance.
Received on Fri Apr 24 1998 - 11:10:54 CDT