SELECT ses.sid, ses.serial#, ses.osuser, ses.process, sio.physical_reads
FROM v$session ses, v$sess_io sio
WHERE ses.sid = sio.sid
AND nvl(ses.username,'SYS') not in ('SYS', 'SYSTEM')
AND sio.physical_reads = (SELECT MAX(physical_reads)
FROM v$session ses2, v$sess_io sio2
WHERE ses2.sid = sio2.sid
AND ses2.username
NOT IN ('SYSTEM', 'SYS'));
FROM v$session ses, v$sess_io sio
WHERE ses.sid = sio.sid
AND nvl(ses.username,'SYS') not in ('SYS', 'SYSTEM')
AND sio.physical_reads = (SELECT MAX(physical_reads)
FROM v$session ses2, v$sess_io sio2
WHERE ses2.sid = sio2.sid
AND ses2.username
NOT IN ('SYSTEM', 'SYS'));