A few good queries to find out why Oracle is running slow...

• Show current table locks:

select
  object_name, 
  object_type, 
  session_id, 
  type,         -- Type of lock
  lmode,        -- lock mode
  request, 
  block, 
  ctime         -- Time elapsed
from
  v$locked_object, all_objects, v$lock
where
  v$locked_object.object_id = all_objects.object_id AND
  v$lock.id1 = all_objects.object_id AND
  v$lock.sid = v$locked_object.session_id
order by
  session_id, ctime desc, object_name

• Currently running queries:

select S.USERNAME, s.sid, s.osuser, t.sql_id, sql_text
from v$sqltext_with_newlines t, V$SESSION s
where t.address =s.sql_address
and t.hash_value = s.sql_hash_value
and s.status = 'ACTIVE'
and s.username <> 'SYSTEM'
order by s.sid,t.piece

• Long-running operations:

COLUMN percent FORMAT 999.99 

SELECT sid, to_char(start_time,'hh24:mi:ss') stime, message,( sofar/totalwork)* 100 percent 
FROM v$session_longops
WHERE sofar/totalwork < 1