Error report:
sql Error: ORA-12953: The request exceeds the maximum allowed database size of 11 GB

select sum(size_in_mb) from 
(
SELECT owner,segment_name,segment_type,sum(bytes)/1024/1024 size_in_mb
  FROM dba_segments
 WHERE owner NOT IN ('SYS','SYSTEM')
 GROUP BY owner,segment_type
 ORDER BY SUM(bytes)/1024/1024
 );

我怎样才能找到在oracle中使用多少空间？