RE: Datafile header surgery

Adam,

Oracle does not document the datafile header format. There are probably a few various papers floating around that document some of the info to some degree, but it's mostly just guess work that people have been able to work out. Also, the bbed tool, which I'm not going to get into great detail on, can also provide some insight into block and header formats.

"The database is in development and therefore isn't backed up..." Hmm...interesting strategy, can't say that I agree, though....

Since you have nothing to lose, first, make a copy of the corrupted datafile, then have at it. Look at non-corrupted data files, maybe you'll be able to fix the problem....?

If you are successful, let us all know about it!

-Mark

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Mark J. Bobak
Senior Oracle Architect
ProQuest Information & Learning

There is nothing so useless as doing efficiently that which shouldn't be done at all. -Peter F. Drucker, 1909-2005

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Donahue, Adam Sent: Wednesday, January 10, 2007 1:08 PM To: oracle-l_at_freelists.org
Subject: Datafile header surgery

Has Oracle (or anyone else) published the header format for database datafiles?

I ask because one of our datafiles was corrupted due to an nStor outage yesterday, and thus is triggered an ORA-01251 when one attempts to recover it:

01251, 00000, "Unknown File Header Version read for file number %s" // *Cause: Read of the file header returned a record but its version cannot
// be identified. Either the header has been corrupted, or the file

//         is not a valid database file.
// *Action: Have the operating system make the correct file available to
//         the database, or recover the file.

The database is in development and therefore isn't backed up, but before rebuilding I thought it might be interesting to attempt a manual hack to the header to get the database to load so that data could be extracted. Any other potential workarounds here?

Adam

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http://www.freelists.org/webpage/oracle-l Received on Wed Jan 10 2007 - 13:22:24 CST