SQL> l
  1  select /*+ parallel (b,2) */ *
  2  from (
  3         select * from PARTY_SERVICE_MODEL_H
  4         union
  5         select * from PARTY_SERVICE_MODEL_H
  6         union
  7         select * from PARTY_SERVICE_MODEL_H
  8         union
  9         select * from PARTY_SERVICE_MODEL_H
 10*      ) b
SQL> /

460 rows selected.


Execution Plan
----------------------------------------------------------
   0      SELECT STATEMENT Optimizer=ALL_ROWS (Cost=13 Card=1840 Bytes=167440)
   1    0   PX COORDINATOR
   2    1     PX SEND* (QC (RANDOM)) OF ':TQ10001' (Cost=13 Card=1840 Bytes=167440)
   3    2       VIEW* (Cost=13 Card=1840 Bytes=167440)
   4    3         SORT* (UNIQUE) (Cost=13 Card=1840 Bytes=69920)
   5    4           PX RECEIVE*
   6    5             PX SEND* (HASH) OF ':TQ10000'
   7    6               UNION-ALL*
   8    7                 PX BLOCK* (ITERATOR) (Cost=2 Card=460 Bytes=17480)
   9    8                   TABLE ACCESS* (FULL) OF 'PARTY_SERVICE_MODEL_H' (TABLE) (Cost=2 Card=460 Bytes=17480)
  10    7                 PX BLOCK* (ITERATOR) (Cost=2 Card=460 Bytes=17480)
  11   10                   TABLE ACCESS* (FULL) OF 'PARTY_SERVICE_MODEL_H' (TABLE) (Cost=2 Card=460 Bytes=17480)
  12    7                 PX BLOCK* (ITERATOR) (Cost=2 Card=460 Bytes=17480)
  13   12                   TABLE ACCESS* (FULL) OF 'PARTY_SERVICE_MODEL_H' (TABLE) (Cost=2 Card=460 Bytes=17480)
  14    7                 PX BLOCK* (ITERATOR) (Cost=2 Card=460 Bytes=17480)
  15   14                   TABLE ACCESS* (FULL) OF 'PARTY_SERVICE_MODEL_H' (TABLE) (Cost=2 Card=460 Bytes=17480)


   2 PARALLEL_TO_SERIAL
   3 PARALLEL_COMBINED_WITH_PARENT
   4 PARALLEL_COMBINED_WITH_PARENT
   5 PARALLEL_COMBINED_WITH_PARENT
   6 PARALLEL_TO_PARALLEL
   7 PARALLEL_COMBINED_WITH_PARENT
   8 PARALLEL_COMBINED_WITH_CHILD
   9 PARALLEL_COMBINED_WITH_PARENT
  10 PARALLEL_COMBINED_WITH_CHILD
  11 PARALLEL_COMBINED_WITH_PARENT
  12 PARALLEL_COMBINED_WITH_CHILD
  13 PARALLEL_COMBINED_WITH_PARENT
  14 PARALLEL_COMBINED_WITH_CHILD
  15 PARALLEL_COMBINED_WITH_PARENT


Statistics
----------------------------------------------------------
         12  recursive calls
          0  db block gets
         68  consistent gets
          0  physical reads
          0  redo size
      24018  bytes sent via SQL*Net to client
       1506  bytes received via SQL*Net from client
         32  SQL*Net roundtrips to/from client
          6  sorts (memory)
          0  sorts (disk)
        460  rows processed