Script – Sessions with high physical reads

 set linesize 120
col os_user format a10
col username format a15

col pid format 9999999999
PROMPT SESSIONS SORTED BY PHYSICAL READS
PROMPT
select
  OSUSER os_user,username,
    PROCESS pid,
    ses.SID sid,
    SERIAL#,
    PHYSICAL_READS,
     BLOCK_CHANGES
 from       v$session ses,
   v$sess_io sio
  where      ses.SID = sio.SID
and username is not null
and status='ACTIVE'
 order      by PHYSICAL_READS;