Distribution of relations in parallel database based on PC clusters

In parallel database system, optimizing distribution of relations could improve processing efficiency of multi-join queries greatly. The cost of data communication is expensive in parallel system based on PC clusters. This paper proposes distribution of relations algorithm to select an appropriate data placement strategy for each relation, which includes selection of distribution attributes and nodes. The algorithm could make best use of intra-operator parallelism, independent inter-operator parallelism and pipelined parallelism of PC clusters system. At the same time, it could reduce additional communication cost of data redistribution. The result of experiment indicates the algorithm has good performance and contributes to promoting execution efficiency of parallel multi-join queries.