오라클 많은 I/O 일어나는 상위 30개 테이블

select table_name,total_phys_io
from ( select owner||'.'||object_name as table_name,
               sum(value) as total_phys_io
         from   v$segment_statistics
         where  owner!='SYS' and object_type='TABLE'
 and  statistic_name in ('physical reads','physical reads direct',
                         'physical writes','physical writes direct')
         group by owner||'.'||object_name
         order by total_phys_io desc)
 where rownum <=30;