Oracle建立新undo表空間最佳實踐(包含段檢查)

在處理一則ORA-600 [4194]案例時，參考MOS文檔：Step by step to resolve ORA-600 4194 4193 4197 on database crash (文檔 ID 1428786.1)

• 1.對於ORA 600[4194]的解釋
• 2.建立新undo表空間最佳實踐(包含段檢查)

1.對於ORA 600[4194]的解釋：

The following error is occurring in the alert.log right before the database crashes.
ORA-00600: internal error code, arguments: [4194], [#], [#], [], [], [], [], []
 
This error indicates that a mismatch has been detected between redo records and rollback (undo) records.

ARGUMENTS:

Arg [a] - Maximum Undo record number in Undo block
Arg [b] - Undo record number from Redo block

Since we are adding a new undo record to our undo block, we would expect that the new record number is equal to the maximum record number in the undo block plus one. Before Oracle can add a new undo record to the undo block it validates that this is correct. If this validation fails, then an ORA-600 [4194] will be triggered.

能夠看到，此錯誤是由於redo和undo的記錄不匹配。常見於異常斷電等場景。

2.建立新undo表空間最佳實踐(包含段檢查)

Best practice to create a new undo tablespace.
This method includes segment check.

1. Create pfile from spfile to edit
SQL> Create pfile='/tmp/initsid.ora' from spfile;

2. Shutdown the instance

3. set the following parameters in the pfile /tmp/initsid.ora
    undo_management = manual
    event = '10513 trace name context forever, level 2'

4. SQL>>startup restrict pfile='/tmp/initsid.ora'

5. SQL>select tablespace_name, status, segment_name from dba_rollback_segs where status != 'OFFLINE';

This is critical - we are looking for all undo segments to be offline - System will always be online.

If any are 'PARTLY AVAILABLE' or 'NEEDS RECOVERY' - Please open an issue with Oracle Support or update the current SR.  There are many options from this moment and Oracle Support Analyst can offer different solutions for the bad undo segments.

If all offline then continue to the next step

6. Create new undo tablespace - example
SQL>create undo tablespace <new undo tablespace> datafile <datafile> size 2000M;

7. Drop old undo tablespace
SQL>drop tablespace <old undo tablespace> including contents and datafiles;

8. SQL>shutdown immediate;

9 SQL>startup nomount;  --> Using your Original spfile

10. Modify the spfile with the new undo tablespace name

SQL> Alter system set undo_tablespace = '<new tablespace created in step 6>' scope=spfile;

11. SQL>shutdown immediate;

12. SQL>startup;  --> Using spfile

相關隨筆參考：

• 如何刪除回滾段狀態爲NEEDS RECOVERY的undo表空間