Oracle Session physical I/O

If you are a DBA that is just concerned with physical I/O, then the physpctio.sql  query will provide the information you need:

This script queries the sys.v_$statname, sys.v_$sesstat, sys.v_$session, and sys.v_$bgprocess views.

select sid, username, round(100 * total_user_io / total_io, 2) tot_io_pct
  from (select b.sid sid,
               nvl(b.username, p.name) username,
               sum(value) total_user_io
          from sys.v_$statname  c,
               sys.v_$sesstat   a,
               sys.v_$session   b,
               sys.v_$bgprocess p
         where a.statistic# = c.statistic#
           and p.paddr(+) = b.paddr
           and b.sid = a.sid
           and c.name in ('physical reads',
                          'physical writes',
                          'physical writes direct',
                          'physical reads direct',
                          'physical writes direct (lob)',
                          'physical reads direct (lob)')
         group by b.sid, nvl(b.username, p.name)),
       (select sum(value) total_io
          from sys.v_$statname c, sys.v_$sesstat a
         where a.statistic# = c.statistic#
           and c.name in ('physical reads',
                          'physical writes',
                          'physical writes direct',
                          'physical reads direct',
                          'physical writes direct (lob)',
                          'physical reads direct (lob)'))
 order by 3 desc;

 

http://www.dba-oracle.com/oracle_tips_top_session.htm