select d.value || '/' || lower(rtrim(i.instance, chr(0))) || '_ora_' ||
p.spid || '.trc'
from (select p.SPID
from v$mystat m, v$session s, v$process p
where m.statistic# = 1
and s.sid = m.sid
and p.addr = s.paddr) p,
(select t.instance
from v$thread t, v$parameter v
where v.name = 'thread'
and (v.value = 0 or t.thread# = to_number(v.value))) i,
(select value from v$parameter where name = 'user_dump_dest') d;