DBA SGA Wait Event Summary (active session history)

select
100*gash.seconds/xxen_util.zero_to_null(sum(gash.seconds) over (partition by &gash_inst_id 1)) percentage,
gash.seconds/gash.total_seconds active_sessions,
xxen_util.time(gash.seconds) time,
&gash_inst_id
gash.seconds,
gash.wait_class,
&gash_event
xxen_util.time(gash.total_seconds) time_window
from
(
select distinct
&gash_inst_id
count(*) over (partition by &gash_inst_id gash.wait_class,&gash_event 1) seconds,
nvl(gash.wait_class,'ON CPU') wait_class,
&gash_event
(max(cast(gash.sample_time as date)) over (partition by &gash_inst_id 1)-min(cast(gash.sample_time as date)) over (partition by &gash_inst_id 1))*86400 total_seconds
from
gv$active_session_history gash
where
1=1
) gash
order by
&gash_inst_id
seconds desc

select 100*gash.seconds/xxen_util.zero_to_null(sum(gash.seconds) over (partition by &gash_inst_id 1)) percentage, gash.seconds/gash.total_seconds active_sessions, xxen_util.time(gash.seconds) time, &gash_inst_id gash.seconds, gash.wait_class, &gash_event xxen_util.time(gash.total_seconds) time_window from ( select distinct &gash_inst_id count(*) over (partition by &gash_inst_id gash.wait_class,&gash_event 1) seconds, nvl(gash.wait_class,'ON CPU') wait_class, &gash_event (max(cast(gash.sample_time as date)) over (partition by &gash_inst_id 1)-min(cast(gash.sample_time as date)) over (partition by &gash_inst_id 1))*86400 total_seconds from gv$active_session_history gash where 1=1 ) gash order by &gash_inst_id seconds desc