Techniques are provided for increasing the degree of parallelism without
incurring overhead costs associated with inter-nodal communication for performing
parallel operations. One aspect of the invention is to distribute-phase partition-pairs
of a parallel partition-wise operation on a pair of objects among the nodes of
a database system. The -phase partition-pairs that are distributed to each node
are further partitioned to form a new set of-phase partition-pairs. One -phase
partition-pair from the set of new-phase partition-pairs is assigned to each slave
process that is on a given node. In addition, a target object may be partitioned
by applying an appropriate hash function to the tuples of the target object. The
parallel operation is performed by broadcasting each tuple from a source table
only to the group of slave processes that is working on the static partition to
which the tuple is mapped.