text: col tablespace_name format a30
  col file_name format a60
  col autoextensible format a3
  col MB format 9999999.99
  col MaxMB format 9999999.99
  set lines 200
  select tablespace_name,file_name,bytes/(1024*1024) MB, autoextensible, maxbytes/(1024*1024) MaxMB
  from dba_data_files where tablespace_name in
  (select upper(value) from gv$parameter where name='undo_tablespace')
  order by tablespace_name;
  