Undo datafile recover

Question

hi
In undo tablespace 3 datafiles are there one datafile damaged now wt is the statud of database.
how can i recover that corrupted file.

Answer 1

Hi.You say that your database running in archivelog mode then you can try *"alter database create datafile as"* if this statement does not any effect then you need drop this datafile and you can create new undo tablespace then switch this tablespace.Following example will help you.
1.Backup your database.
2.Delete from OS level this/corrupted datafile then
C:\Documents and Settings\chinar>sqlplus "sys/sm as sysdba"
SQL*Plus: Release 10.2.0.2.0 - Production on Tue Jun 22 11:50:02 2010
Copyright (c) 1982, 2005, Oracle.  All Rights Reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - Production
With the Partitioning, OLAP and Data Mining options
SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     1
Next log sequence to archive   3
Current log sequence           3
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area  138412032 bytes
Fixed Size                  1288172 bytes
Variable Size              67110932 bytes
Database Buffers           62914560 bytes
Redo Buffers                7098368 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 6 - see DBWR trace file
ORA-01110: data file 6: 'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\UNDOTBS3'
SQL> alter database create datafile  'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\UNDO
TBS3' as  'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\UNDOTBS3';
Database altered.
SQL> recover datafile  'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\UNDOTBS3';
Media recovery complete.
SQL> alter database open;
Database altered.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area  138412032 bytes
Fixed Size                  1288172 bytes
Variable Size              67110932 bytes
Database Buffers           62914560 bytes
Redo Buffers                7098368 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 6 - see DBWR trace file
ORA-01110: data file 6: 'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\UNDOTBS3'
SQL> alter database datafile  'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\UNDOTBS3' o
ffline drop;
Database altered.
SQL> alter database open;
Database altered.
SQL>If you can not do these then create new undo tablespace then switch to this.In additionally see below link
http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/undo.htm#i1106407
Edited by: Chinar on Jun 22, 2010 12:06 AM