to_char(round(sub1.sample_time, 'MI'), 'YYYY-MM-DD HH24:MI') as sample_minute,

round(avg(sub1.on_cpu),1) as cpu_avg,

round(avg(sub1.waiting),1) as wait_avg,

round(avg(sub1.active_sessions),1) as act_avg,

round( (variance(sub1.active_sessions)/avg(sub1.active_sessions)),1) as act_var_mean

( -- sub1: one row per second, the resolution of SAMPLE_TIME

select

sample_id,

sample_time,

sum(decode(session_state, 'ON CPU', 1, 0)) as on_cpu,

sum(decode(session_state, 'WAITING', 1, 0)) as waiting,

count(*) as active_sessions

from

v$active_session_history

where

sample_time > sysdate - (&minutes/1440)

group by

sample_id,

sample_time

) sub1

round(sub1.sample_time, 'MI')

round(sub1.sample_time, 'MI')

;