Abstract:

Multijoin query optimization is one of the key problems in database searching. As multicores replace traditional single processor because of the advantages of their high performance and low energy consumption, researches on bottomup dynamic query parallel algorithms have become popular. However,  the advantages of topdown dynamic query algorithm  can not be replaced by bottomup dynamic query algorithms, such as cut algorithm. Based on bottomup and topdown algorithms, this paper proposes a graph traversal twoway optimization algorithm  on the multicores system. The proposed approach makes full use of the  advantages of both topdown and bottomup algorithms, gives full play to multicores environments, realizes high performance parallel construction of optimal query plans, thus resolves parallel twoway enumeration join problem. Experimental result shows that the proposed algorithm outperforms existing algorithms, and can effectively increase the speed of database query.

Key words: multicores, query optimization, joinenumeration, dynamic programming