V$PQ_SESSTAT
lists session statistics for parallel queries. After you have run a query or DML operation, you can use the information derived from V$PQ_SESSTAT
to view the number of slave processes used, and other information for the session and system.
Column  Datatype  Description 

STATISTIC 
VARCHAR2(30) 
Name of the statistic:

LAST_QUERY 
NUMBER 
Value of the statistic for the last operation 
SESSION_TOTAL 
NUMBER 
Value of the statistic for the entire session to this point in time 