session
on: dbms_system.set_ev(sid,serial#,10046,level,'');
off: dbms_system.set_ev(sid,serial#,10046,0,'');
system wide
on: alter system set events '10046 trace name context forever, level <level>';
off: alter system set events '10046 trace name context off';

levels
4=binds
8=waits
12=binds and waits