Enabling intra-partition parallelism for partition-based operations

摘要

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.