V$PX_SESSION the sessions running parallel execution

What are parallel sessions?


select qcsid, count(1) from v$px_session group by qcsid;

QCSID field means Query Coordinator, main session that coordinates slave sessions.

Details.... 

COL USERNAME FOR A16 HEADING 'Username'

COL MACHINE FOR A24 HEADING 'Machine'

COL PROGRAM FOR A33 HEADING 'Program'

COL OSUSER FOR A14 HEADING 'OS | User'

COL QC FOR A3

ALTER SESSION SET NLS_DATE_FORMAT='DD-MON-YYYY HH24:MI:SS';

SET LIN 150

SET PAGES 103

compute sum LABEL 'Total Memory'    of memory_mb on report

compute count LABEL 'Count Parallel' of sid on report

undefine SID

break on report

select s.sid,decode(pxs.sid, pxs.qcsid,'X',NULL) QC ,  s.username, s.osuser, p.spid "OS PID", s.program,s.machine, status,s.logon_time,round(p.PGA_ALLOC_MEM/1024/1024) memory_mb

from v$session s, v$process p, v$px_session pxs

Where s.paddr = p.addr and s.sid=pxs.sid and   pxs.qcsid = &SID

order by (p.spid-s.process)* (p.spid-s.process) desc;

Remember, you clear sum and count in the report in order to not affect other queries... ;)

CLEAR COMPUTES

Regards,

Eini Trujillo