I just saw a thread with this subject (initiated today by s_radhak), but the thread was allready closed !?! Btw, who decides when to close a particular thread? The original poster? The moderators?

Anyway, s_radhak wanted to know how to determine which background process is running in which session and I have a feeling he haven't got the answer yet. So here it is. There is a dynamic performance view called V$BGPROCESS which lists all the possible background proceses, both those that are actualy started and also those that arent (but are available). If you join this view to V$SESSION by process address you'll get all the background proceses listed with current sessions.

SELECT s.sid, s.username, s.process, s.program, b.description background
FROM v$session s, v$bgprocess b
WHERE s.paddr = b.paddr(+);

HTH,