col c1 heading 'Average Waits|for Full| Scan Read I/O'        format 9999.999
col c2 heading 'Average Waits|for Index|Read I/O'               format 9999.999
col c3 heading 'Percent of| I/O Waits|for Full Scans'              format 99
col c4 heading 'Percent of| I/O Waits|for Index Scans'           format 99
col c5 heading 'Starting|Value|for|optimizer|index|cost|adj'      format 999

select
  a.average_wait                                      c1,
  b.average_wait                                      c2,
  a.total_waits /(a.total_waits + b.total_waits)*100  c3,
  b.total_waits /(a.total_waits + b.total_waits)*100  c4,
  (b.average_wait / a.average_wait)*100               c5
from
  v$system_event  a,
  v$system_event  b
where
  a.event = 'db file scattered read'
and
  b.event = 'db file sequential read';

Labels: Oracle