DBWR performance issue

 
Hi,

While troubleshooting one of our database (10.2.0.4 on HP Open VMS with a single CPU)  for slow performance, we are using the following query to determine TOP sessions


  1  select
  2     sid,
  3     username,
  4     round(100 * total_user_io/total_io,2) tot_io_pct
  5  from
  6  (select
  7       b.sid sid,
  8       nvl(b.username,p.name) username,
  9       sum(value) total_user_io
 10   from
 11       sys.v_$statname c,
 12       sys.v_$sesstat a,
 13       sys.v_$session b,
 14       sys.v_$bgprocess p
 15   where
 16        a.statistic#=c.statistic# and
 17        p.paddr (+) = b.paddr and
 18        b.sid=a.sid and
 19        c.name in ('physical reads',
 20                   'physical writes',
 21                   'physical writes direct',
 22                   'physical reads direct',