List connected sessions

Show connected sessions, join of v$session and v$process

select s.*, p.*
  from gv$session s
     , gv$process p
 where p.addr = s.paddr
   and p.inst_id = s.inst_id;

Filter some accounts that we often don't want to see

select s.*, p.*
  from gv$session s
     , gv$process p
 where p.addr = s.paddr
   and p.inst_id = s.inst_id
   and s.username is not null
   and s.username not in ('SYS', 'SYSTEM', 'DBSNMP')
 order by s.last_call_et desc;