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Abstract : |
In this paper, we describe our approach to the compile-time optimization and parallelization of queries for execution in DBS3, a shared-memory parallel database system. Our approach enables exploring a search space large enough to include zigzag trees which are intermediate between left-deep and rightdeep trees. Zigzag trees are shown to provide better response time than right-deep trees in the case of limited memory. Because DBS3 implements a parallel dataflow execution model, this approach applies to both shared-memory and distributed-memory architectures. Performance measurements run using the DBS3 prototype show the advantages of zigzag trees under various conditions. 1, |
