Optimization of multi-join queries in shared-nothing systems
- 15 Downloads
This paper proposes a semi-greedy framework for optimizing multi-join queries in shared-nothing systems. The plan generated by the framework comprises several pipelines, each performing several joins. The framework determines the “optimal” number of joins to be performed in each pipeline. The decisions are made based on the cost estimation of the entire processing plan. Two existing optimization algorithms are extended under the framework. An analytical model is presented and used to compare the quality of plans produced by each optimization algorithm. Our study shows that the new algorithms outperform their counterparts that are not extended.
KeywordsMulti-join optimization shared-nothing systems pipelining hash join segmented right-deep tree
Unable to display preview. Download preview PDF.
- Chen M S, Lo M L, Yu P S, Young H C. Using segmented right-deep trees for the execution of pipelined hash joins. In18th VLDB Conf., Aug. 1992, pp. 15–26.Google Scholar
- DeWitt D J, Gerber R. Multiprocessor hashed-based join algorithms. In11th VLDB Conf., Aug. 1985, pp. 151–164.Google Scholar
- Hua K A, Lee C. Handling data skew in multiprocessor database computers using partition tuning. In17th VLDB Conf., 1991, pp. 525–535.Google Scholar
- Hua K A, Lo Y L, Young B C. Including the load balancing issue in the optimization of multi-way join queries for shared-nothing database computers. In2nd PDIS Conf., 1993, pp. 74–83.Google Scholar
- Ono K, Lohman G. Measuring the complexity of join enumeration in relational query optimization. In16th VLDB Conf., 1990, pp. 314–324.Google Scholar
- Schneider D A, DeWitt D J. Tradeoffs in processing complex join queries via hashing in multiprocessor database machines. In16th VLDB Conf., Sept. 1990.Google Scholar
- Shekita E J, Young H C, Tan K L. Multi-join query optimization for symmetric multiprocessors. In19th VLDB Conf., Aug. 1993.Google Scholar
- Tan K L, Lu H. Skew-handling strategies for pipelined processing of multi-join queries in shared-nothing systems.International Journal of Computer Systems and Engineering. (to be published).Google Scholar