Oracle Database Discussions

How to find the pid,sppid for a session.

SQL> select sid,serial# from v$session where username='TEST';

SID SERIAL#
--------- ---------
23 38104
Now i want to find PID and SPID for session 23

SQL>select a.sid,a.serial#,b.pid,b.spid from v$session a,v$process b where a.serial#=b.serial#
and a.sid=23

no rows selected

I am not getting pid and spid even though user test with sid 23 is connected and its status is inactive.
Thank you