Oracle Database Discussions

Dear all,

Let's start from the beginning, During one operational job i increase the size of the my undo tablespace.After the work is done i created another undo tablespace and set that as my undo_tablespace.Later i drop my old undo tablespace and recreate it.after that i switch to that tablespace.And drop the other one.My motive was to get my undo tablespace with his real size and real name.But when i restarted the database,It shows error and the database remain in mounted stage,so i had to startup the database with existing pfile. But the day after,when i restarted the database,it show error again but the database was up.Previously,when i start the oracle service the database was auto up.But now i have to write startup command to open the database.Here is a glance of my alert log file:

MON: enabling cache recovery
Sat Jul 17 08:22:10 2010
Errors in file d:\oracle\admin\twr\udump\twr_ora_932.trc:
ORA-30012: undo tablespace 'UNDOXX' does not exist or of wrong type

Sat Jul 17 08:22:10 2010
Error 30012 happened during db open, shutting down database
USER: terminating instance due to error 30012
Sat Jul 17 08:22:10 2010
Errors in file d:\oracle\admin\twr\bdump\twr_pmon_968.trc:
ORA-30012: undo tablespace '' does not exist or of wrong type

Sat Jul 17 08:22:11 2010
Errors in file d:\oracle\admin\twr\bdump\twr_reco_1868.trc:
ORA-30012: undo tablespace '' does not exist or of wrong type

Sat Jul 17 08:22:11 2010
Errors in file d:\oracle\admin\twr\bdump\twr_smon_1864.trc:
ORA-30012: undo tablespace '' does not exist or of wrong type

Sat Jul 17 08:22:11 2010
Errors in file d:\oracle\admin\twr\bdump\twr_ckpt_1900.trc:
ORA-30012: undo tablespace '' does not exist or of wrong type

Sat Jul 17 08:22:11 2010
Errors in file d:\oracle\admin\twr\bdump\twr_lgwr_1904.trc:
ORA-30012: undo tablespace '' does not exist or of wrong type

Sat Jul 17 08:22:11 2010
Errors in file d:\oracle\admin\twr\bdump\twr_dbw0_1908.trc:
ORA-30012: undo tablespace '' does not exist or of wrong type

Instance terminated by USER, pid = 932
ORA-1092 signalled during: alter database open...
Sat Jul 17 08:22:45 2010
Starting ORACLE instance (normal)...


But i dropped the UNDOXX tablespace and set UNDO as my new Undo tablespace.My db version 9.2.0.8 and os Windows server 2000.Undo managemenet auto.

can any one suggest what should i do
????

Thanks,