prompt entry

Hi,

I try to run the following :

set pages 10000

set long 65536

set linesize 80

break on spid skip page

column osuser format a8 heading "O/SUser"

column process format a7 heading "CPid"

column spid format a7 heading "SPid"

column username format a15 heading "DbUser"

column status format a1 heading "S"

column event format a15 heading "WaitResn"

column wait_time format 99 heading "Time"

accept response prompt "Enter OS User ID, Client PID, or Server PID: "

from here :

Oracle SQL Tuning Guide

Can any one tell me if I should provide all three OS User ID, Client PID, or Server PID ?

Or only one would be enough ? More over how to find the available values from database ?