Oracle Corporation
Adaptive granule generation for parallel queries with run-time data pruning

Abstract:

Techniques herein improve computational efficiency for parallel queries with run-time data pruning by using adaptive granule generation. In an embodiment, an execution plan is generated for a query to be executed by a plurality of slave processes, the execution plan comprising a plurality of plan operators. For a first plan operator of the plurality of plan operators, a first set of work granules is generated, and for a second plan operator of the plurality of plan operators, a second set of work granules is generated. A first subset of slave processes of the plurality of slave processes is assigned the first set of work granules. Based on the execution of the first set of work granules by the first subset of slave processes, a bloom filter is generated that specifies for which of said first set of work granules no output rows were generated. Based on the bloom filter, the second set of work granules is modified and the modified second set of work granules is assigned to a second subset of slave processes and executed.