How to trace other user's session?

Question

Dear Experts,
I would like to trace other user's session, I am on Oracle 10g R2 (10.2.0.4) on a Windows box. I did search on google and found tons of articles explaining about tracing techniques. But unfortunately, trace file is not getting generated in my case. Below are the steps I am following:
SQL> conn /as sysdba
Connected.
SQL>
SQL> select sid, serial# from v$session where username = 'TEST';
       SID    SERIAL#
        38         17
SQL> show parameter user_d
NAME                                 TYPE        VALUE
user_dump_dest                       string      C:\DB10G\UDUMP
SQL> show parameter timed_s
NAME                                 TYPE        VALUE
timed_statistics                     boolean     TRUE
SQL>Connect a new SQL*Plus session as TEST and then
SQL> show user
USER is "SYS"
SQL>
SQL> select sid, serial# from v$session where username = 'TEST';
       SID    SERIAL#
        19      24465
        38         17
SQL> exec dbms_system.set_ev(38,17, 10046, 12, '');
PL/SQL procedure successfully completed.
SQL> exec dbms_system.set_ev(38,17, 10046, 0, '');
PL/SQL procedure successfully completed.
SQL> grant execute on dbms_system to test;
Grant succeeded.
SQL> exec dbms_system.set_ev(38,17, 10046, 12, '');
PL/SQL procedure successfully completed.in the new session (TEST):
SQL> select * from tab;
TNAME                          TABTYPE  CLUSTERID
T                              TABLE
T3                             TABLE
T1                             TABLE
T2                             TABLE
MYEMP                          TABLE
SQL>Yet, no trace file is generated in "C:\db10g\udump" folder.
C:\db10g\udump>dir
Volume in drive C is SYSTEM
Volume Serial Number is AC21-0462
Directory of C:\db10g\udump
12/15/2008  12:36 PM    <DIR>          .
12/15/2008  12:36 PM    <DIR>          ..
               0 File(s)              0 bytes
               2 Dir(s)   9,891,508,224 bytes free
C:\db10g\udump>Your help/advice in this regard will be very helpful.
Regards

Answer 1

You must be using shared server.
You can verify this by referring to the SERVER column of v$session.
In shared server several servers will execute your code, so that's why you don't find a trace file.
The method described in this article should work in your case also:
http://technology.amis.nl/blog/1794/how-to-trace-a-java-application-through-a-connection-pool-using-dbms_monitor-6
Hth
Sybrand Bakker
Senior Oracle DBA