RE: System datafile corruption.

Mike:

Have you upgraded versions lately? We had the same error pop up in our System tablespace, but the 'problem' wasn't real. It was an artifact left over from the upgrade of (I think) 7.x to 8.x. There are parts of the SYSTEM rollback segment that had never been touched, and these showed up as corrupt in dbv. Look in MetaLink, that's where we found the problem and the solution. The solution was to create a script that used the SYSTEM rollback segment for many (MANY) transactions and used up all the available extents in that rollback segment. Once it ran, dbv was happy.

Good Luck!
Mike

-----Original Message-----
Sent: Thursday, April 18, 2002 6:28 AM
To: Multiple recipients of list ORACLE-L

Guys,

        I have a system datafile that returns dbv errors for a SYSTEM datafile.

The fault has existed for a long time undiscovered so recovery from backup is not possible. The database still does not exhibit any problems except for dbv!
The errors are all 'Block Type = Undo data block', so I assume the fault is in the system rollback segment.

I'm sure I can't drop/recreate the SYSTEM rbs, so does anyone have any suggestions apart from a full export and import?

Dbv extract is below:
>

Block Checking: DBA = 67108870, Block Type = Undo data block

ERROR: Undo Block Corrupted. Error Code = 2008

ktu4ubck: size(108) of undo record #1 corrupted.

UNDO BLK HEADER: xid: 0x0000.08a.00000151 seq: 0x198 cnt: 0x4d irb: 0x4d icl: 0x0 flg: 0x000
0  

 Rec Offset | Rec Offset | Rec Offset | Rec Offset | Rec Offset

0x00 0x1fe8 | 0x01 0x1f80 | 0x02 0x1f2e | 0x03 0x1ee0 | 0x04 0x1e76

.
.
0x4b 0x027c | 0x4c 0x0212 | 0x4d 0x01b0

Hex dump:

0x000b6b94(+0000): 00 0a 00 10 00 3c 00 10 00 02 00 00 2a 11 00 00

.
.
0x000b6bf4(+0060): 00 9d 00 00 78 bc 01 00

>

grep 'Block Type' dbv_log | wc -l

     127

Regards,
Mike Jenner
Database Administrator

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