SHRINKING UNDO TBS
==================

create undo tablespace UNDO_RBS1 datafile '/database/RMREP3/data1/undo02RMREP3.dbf' size 500m;

# instance was started form PFILE
# update PFILE to start instance with different UNDO tablespace is mandatory
# change instance memory parameter
alter system set undo_tablespace=undo_rbs1;

 

# drop old UNDO tablespace
drop tablespace UNDO including contents.



select tablespace_name, status from dba_tablespaces;
 

TABLESPACE_NAME                STATUS
------------------------------ ---------
SYSTEM                         ONLINE
SYSAUX                         ONLINE
TEMP                           ONLINE
UNDO_RBS1                      ONLINE

 

# remove old UNDO file from FS

$ ls -al | grep undo
$ rm -f undo01SID.dbf

 

# file is kept in oracle instance memory, i-node information are not updated
# instance restart in future is required, good for PFILE test aas well