alter session set events '10046 trace name context forever, level 12';
select 1 from dual;
alter session set events '10046 trace name context off';

begin
 DBMS_SESSION.set_sql_trace(sql_trace => true);
end;

select 1 from dual;

begin
 DBMS_SESSION.set_sql_trace(sql_trace => false);
end;

select value from v$parameter where name = 'user_dump_dest'

/u/app/oracle/diag/rdbms/test/TEST/trace

select value from v$parameter where name = 'background_dump_dest'

/u/app/oracle/diag/rdbms/test/TEST/trace