Re: dbv - Found block already marked corrupted

On 01/30/2004 03:46:04 PM, Tim Gorman wrote:

> One further question, though...
> 
> >> Of course, if someone knows a utility to un-flag a block I'm all
> ears.
> 
> Why would anyone want to "unflag" a block that has been flagged as
> corrupt?
> I'm all ears for that...  :-)
> 
> -Tim


Actually, not all corrupt blocks are the same. The definition of a  
corrupt block is "a block with a bad checksum". These bad checksums are
mostly caused by software. I have a ton of experience with "corrupt  
blocks" which came into being after copying production database to  
development database using BCVs. This means hot backup and instance  
recovery. For the reasons of speed, the tables with the computed data  
were created with "NOLOGGING" attribute and when access was attempted  
in the cloned instance, oracle started screaming about "corrupted  
blocks". When the table was truncated  and the data computed again, the  
"corruption" was gone. In other words, so called "corrupt blocks" can
simply be flagged "honest" and reused, if they're empty.
----------------------------------------------------------------
Please see the official ORACLE-L FAQ: http://www.orafaq.com
----------------------------------------------------------------
To unsubscribe send email to:  oracle-l-request@xxxxxxxxxxxxx
put 'unsubscribe' in the subject line.
--
Archives are at http://www.freelists.org/archives/oracle-l/
FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
-----------------------------------------------------------------

Other related posts: