切换undo表空间

create undo tablespace undo_new datafile ‘/u01/oracle/oradata/yscsfhx/newundotbs01.dbf‘ size 5m;

alter system set undo_tablespace=undo_new scope=both; 

drop tablespace UNDOTBS1 including contents and datafiles;

lsof | grep deleted

startup force

select b.FILE_NAME, b.TABLESPACE_NAME, b.blocks, b.STATUS, b.AUTOEXTENSIBLE
  from dba_data_files b
 where b.TABLESPACE_NAME like ‘%UNDO%‘;