Undo tablespace currupt and no clean backup

Question

Hello,
We are facing critical problem with database. We have not any clean backup and database in no archive log mode. Suddenly database is shutdown and when we are trying to open database it is giving error:-
ORA-01172: recovery of thread 1 stuck at block 350230 of file 3
ORA-01151: use media recovery to recover block, restore backup if needed
File 3 is Undo file.
Is there any way to open database?
Thanks in advance and please reply us ASAP.

Answer 1

1) First, follow Howardjr recomendations and allways do a backup first.
2) Open a SR with Metalink to help with your problem
3) If you want to try something here are some options, but never skip the point 1 previously explained.
Well, you have two possible scenarios, one supported other unsupported.
This is an inconsistency issue..
Solution
============
*1]Supported Solution:*
Restore-Incomplete recovery the DB from backup or rebuild the DB using an export dump.
*2]Internal (Not-supported) Solution:*
Update undo$ to change the status$ = 1 (undo segment is dropped) for the corrupted undo segment.
Caution:
This is NOT a supported solution. Therefore ensure that a full database cold backup is taken bbefore doing this data-dictionary patching.
Steps to do the patching:
1) First ensure that a full database backup is taken.
2) Modify/add the following parameters in initSID.ora:
undo_management=manual
job_queue_processes =0
aq_tm_processes=0
systemtrig_enabled=false
3) Shutdown
4) Startup restrict pfile
5) set transaction use rollback segment system;
if set transaction above fails, then not to proceed further.
6) Update undo$ to change the status$ = 1 (undo segment is dropped) for
the corrupt undo segment.
update undo$ set status$ = 1
where us# = <'undo segment id'>
and ts#=<'tablespace id'>
and file#=<'file id'>
and block# = <'block id'>
and status$=2;
or
update undo$ set status$ = 1
where name = <'corrupt undo segment name'>
and status$=2;
This will update only 1 row. Rollback the update if more than 1 row is updated.
7) Commit;
8) Shutdown abort
9) Set back in init.ora parameters modified in Step 2.
Startup restrict
10) Drop the corrupt undo tablespace using command:
drop tablespace <corrupt undo tablespace name> including contents;
11) Create new undo tablespace.
In initSID.ora, set undo_management=auto, undo_tablespace=<'new undo tablespace name'>
Restart the instance.
12) Take a backup.
*Parameter offlinerollback_segments is not useful:*
Trying to drop the corrupt undo segment or the undo tablespace by setting parameters undo management=manual and offline_rollback_segments in initSID.ora will fails with error: ORA-00600 [ktssdrp1].
To see the information about the corrupt block use this query:
select us#, name, ts#, file#, block#,status$ from undo$
where (ts#, file#, block#) not in
(select ts#, file#, block# from seg$ where type# in (1,10)) and status$ > 1;I had the same problem some time ago, and the unsupported solution works great, but never try it without a full backup first.
Cheers,
Francisco Munoz Alvarez
http://oraclenz.wordpress.com
Edited by: F.Munoz Alvarez on Nov 30, 2012 11:03 AM