Oracle system parameter had changed ?

changed parameter information



select snap_id,
to_char(end_interval_time,'yyyy/mm/dd hh24:mi:ss') end_interval_time ,
parameter_name,
bef_value,
value cur_value,
isdefault,
ismodified
from (select p.snap_id,
s.end_interval_time,
p.parameter_name,
lag(p.value,1) over(partition by p.instance_number , p.parameter_name order by p.snap_id ) bef_value,
p.value,
p.isdefault,
p.ismodified,
min(p.snap_id) over() min_snap_id
from dba_hist_parameter p,
(select dbid,
instance_number,
max(a.end_interval_time) end_interval_time,
max(snap_id) last_snap_id
from dba_hist_snapshot a
where dbid = (select dbid from v$database)
and instance_number = (select instance_number from v$instance)
group by dbid, instance_number, trunc(end_interval_time)) s
where p.dbid = s.dbid
and p.instance_number = s.instance_number
and p.snap_id = s.last_snap_id
)
where snap_id != min_snap_id
and (value != bef_value or (bef_value is null and value is not null))