rdbms: trace session with logon trigger

Just a simple logon trigger to trace an user session:

create or replace trigger set_session_trace after logon on database

begin
if user ='$USER' then
  execute immediate 'alter session set timed_statistics = true';
  execute immediate 'alter session set max_dump_file_size = unlimited';
  execute immediate 'alter session set tracefile_identifier = ''trace_session_$USER''';
  execute immediate 'alter session set events ''10046 trace name context forever, level 12'' ';
end if;
end;
/

$USER: username

Trace levels (10046):

0: Turn off
1: Basic sql trace ( equal to alter session set sql_trace=true )
4: Level 1 plus bind variables
8: Level 1 plus wait events
12: Level 1 plus bind variables and wait event information