查看oracle sql资源占用过多的sql

SELECT ROWNUM top, t.*
  FROM (SELECT   x.CPU_TIME/x.executions per_cpu, x.hash_value, x.sql_text
            FROM v$sqlarea x
           WHERE x.executions>0
             AND x.parsing_user_id <>0
        ORDER BY x.CPU_TIME/x.executions DESC) t
WHERE ROWNUM < 21