(~)VLDB Considering Data Skew Factor in Multi-Way Join Query Optimization for Parallel Execution

Abstract. A consensus on parallel architecture for very large database manage-ment has emerged. This architecture is based on a shared-nothing hardware or-ganization. The computation model is very sensitive to skew in tuple distribu-tion, however. Recently, several parallel join algorithms with dynamic load bal-ancing capabilities have been proposed to address this issue, but none of them consider multi-way join problems. In this article we propose a dynamic load bal-ancing technique for multi-way joins, and investigate the effect of load balancing on query optimization. In particular, we present a join-ordering strategy that takes load-balancing issues into consideration. Our performance study indicates that the proposed query optimization technique can provide very impressive performance improvement over conventional approaches. Key Words. Parallel-database computer, load balancing, multi-way join, query op-timization