physical reads

 select snap_id,tsname,phyrd_delta,phywrts_delta, round(phyrd_delta/ 3751,0) Avg_reads_sec, round((readtim_delta / phyrd_delta) * 10, 1) avg_reads_ms , round(phywrts_delta / 3751, 0) avg_write_s
from (
SELECT e.snap_id, e.tsname, sum(e.phyrds) - lag(sum(e.phyrds),1) over (partition by e.tsname order by e.snap_id,e.tsname) phyrd_delta , sum(e.readtim) - lag(sum(e.readtim),1) over (partition by e.tsname order by e.snap_id,e.tsname) readtim_delta , sum(e.phywrts) - lag(sum(e.phywrts),1) over (partition by e.tsname order by e.snap_id,e.tsname) phywrts_delta, sum(e.writetim) - lag(sum(e.writetim),1) over (partition by e.tsname order by e.snap_id,e.tsname) writetim_delta
FROM dba_hist_filestatxs e
WHERE e.snap_id between 42265 and 42266
--and e.file# = 177
group by snap_id, e.tsname order by phyrd_delta + phywrts_delta desc
--, e.tsname
)
where phyrd_delta > 0 and rownum < 15 order by phyrd_delta+phywrts_delta desc, tsname