In 11g SQL*Plus, when session is terminated, somehow it displays the process ID, SID and Serial#. Not quite sure what is really for? I guess it is for debugging purpose.
10g Client
user @db10w1> select * from dual; select * from dual * ERROR at line 1: ORA-01012: not logged on
11g Client
user @db10w1> select * from dual; select * from dual * ERROR at line 1: ORA-01012: not logged on Process ID: 0 Session ID: 135 Serial number: 29158
