Hi,
on 10g R2, I follow this article :
http://www.dba-oracle.com/concepts/query_wait_events.htm
Then,
SQL> Select wait_class, sum(time_waited), sum(time_waited)/sum(total_waits)
Sum_Waits
From v$system_wait_class
Group by wait_class
Order by 3 desc; 2 3 4 5
WAIT_CLASS SUM(TIME_WAITED) SUM_WAITS
---------------------------------------------------------------- ---------------- ----------
Idle 25575055 20.4177384
Other 2742 2.70414201
Administrative 49 2.45
SQL> Select a.event, a.total_waits, a.time_waited, a.average_wait
2 From v$system_event a, v$event_name b, v$system_wait_class c
3 Where a.event_id=b.event_id
4 And b.wait_class#=c.wait_class#
5 And c.wait_class in ('Other')
order by average_wait desc; 6
EVENT TOTAL_WAITS TIME_WAITED AVERAGE_WAIT
-------------------------------------------------- ----------- ----------- ------------
control file heartbeat 1 391 390.71
rdbms ipc reply 15 311 20.7
enq: CF - contention 43 647 15.04
kksfbc child completion 8 35 4.41
SQL> select a.sid, a.event, a.total_waits, a.time_waited, a.average_wait
from v$session_event a, v$session b
where time_waited > 0
and a.sid=b.sid
and b.username is not NULL
and a.event='control file heartbeat';
no rows selected
Then why there is no row for control file heartbeat wait event in v$session_event a, v$session b ?
Thank you.