Re: recovery without restoring backup

niy38_at_hotmail.com wrote:
> version is: 10.2.0.1.0
>
> database is running normal until developer complain this error:
>
> ORA-01552: cannot use system rollback segment for non-system tablespace
> 'USERS'
>
>
> I check dba_rollback_segs where all status are "needs recovery", and
> status of
> v$datafile of datafiles for undo is "recovery".
>
> then I "shutdown immediate", and after I start, database can open and
> undo still
> in the same status.
>
> I shutdown again and startup mount, run "recever tablespace undo", and
> it's set.

The data necessary to recover the undo tablespace was in the online redo logs. This can happen on an IO error where Oracle cannot write to a file. If the IO error clears then when you tell Oracle to recover the datafile (or tablespace) and Oracle can write to the file then all is well. At least until the cause of the error corrupts then entire disk. That is, you might need to check the system logs for signs of a hardwar problem. The cause might just be one of those things and not re-occur but you should still look the system over.

As mentioned in the previous response. A failure to be able to write to a file will take it offline so on startup the file was not automatically recovered as part of the transaction recovery process.

HTH -- Mark D Powell -- Received on Thu Nov 30 2006 - 18:52:55 CST