PGA usage for each session

SELECT se.sid,n.name , SUBSTR(s.PROGRAM,INSTR(S.PROGRAM,'(')+1,4) PROCESS_NAME, MAX(se.value) pga_memory, 
       DECODE( r.APPLY_NAME, NULL,  DECODE(coor.APPLY_NAME,NULL, ser.APPLY_NAME, coor.APPLY_NAME),  r.APPLY_NAME ) APPLY_NAM,
       cap.CAPTURE_NAME, q.QNAME, s.USERNAME
FROM v$sesstat se, v$statname n, V$SESSION s, 
 V$STREAMS_APPLY_READER r, V$STREAMS_APPLY_coordinator coor, V$STREAMS_APPLY_SERVER ser,
 GV$STREAMS_CAPTURE c, dba_capture cap ,
 dba_queue_schedules q
WHERE n.statistic# = se.statistic#
AND   s.sid= se.sid
AND n.name IN ('session pga memory')
AND s.SID = r.SID(+) 
AND s.SERIAL# = r.SERIAL#(+)
AND s.SID = coor.SID(+) 
AND s.SERIAL# = coor.SERIAL#(+)
AND s.SID = ser.SID(+) 
AND s.SERIAL# = ser.SERIAL#(+)
AND c.CAPTURE_NAME = cap.CAPTURE_NAME(+)  
AND s.SID            = c.SID(+)
AND s.SERIAL# = c.SERIAL# (+)
AND s.SID            = TO_NUMBER(SUBSTR (q.session_id(+), 1,  INSTR(q.session_id(+), ',')- 1 )) 
AND s.SERIAL# = TO_NUMBER(SUBSTR (q.session_id(+), INSTR(q.session_id(+), ',') +1 ,  LENGTH(q.session_id(+))  - INSTR(q.session_id(+), ',')))
GROUP BY n.name,se.sid, SUBSTR(s.PROGRAM,INSTR(S.PROGRAM,'(')+1,4),DECODE( r.APPLY_NAME, NULL,  DECODE(coor.APPLY_NAME,NULL, ser.APPLY_NAME, coor.APPLY_NAME),  r.APPLY_NAME ), cap.CAPTURE_NAME, q.qname, s.USERNAME
ORDER BY 4 DESC ;

Dba_scheduler_running_jobs

Using DBA_SCHEDULER_RUNNING_JOBS one can see jobs currently running. In the example below it shows the oracle session id and corresponding OS process id.
22:20:51 sys@TESTDB> select job_name, session_id from dba_scheduler_running_jobs;
JOB_NAME SESSION_ID
—————————— ———-
GATHER_STATS_JOB 364
1 row selected.
sys@TESTDB> select program from v$session where sid = 364;
PROGRAM
————————————————
oracle@hostname (J002)
1 row selected.
sys@TESTDB> select vs.program, spid from v$session vs, v$process vp where vs.sid = 364 and vs.paddr = vp.addr
PROGRAM SPID
———————————————— ————
oracle@hostname (J002) 1642698
1 row selected.
Oracle j000 shadow processes are DBMS_SCHEDULER sessions
sys@TESTDB> !ps -ef | grep 1642698
oracle 1642698 1 120 00:00:07 – 1071:14 ora_j002_TESTDB
oracle 13836458 11677872 2 22:23:06 pts/5 0:00 grep 1642698