抗偏斜的并行二元连接算法研究

Research on the Skew Effects of Parallel Data in Binary Hash Join Algorithm

在分析了数据偏斜特点的基础上，提出了一种抗静态和动态数据偏斜的ＨｙｂｒｉｄＳｋｅｗ算法以及代价分析模型．应用本模型对ＨｙｂｒｉｄＳｋｅｗ算法进行分析，结果表明，本算法在网络传输率和磁盘传输率较低的系统和半连接选择率较小、有偏斜的情况下。

On the basis of the analysis of the characteristic of data skew, a hybrid skew hash join algorithm is presented, which can surmount the negative effects of static data skew and motion data skew. In order to analysis the performance of this algorithm, a cost analysis model on several kinds of parameters from a new point is given. We analysis the hybrid skew algorithm using this model, point out that this algorithm fits for the system with relatively low network bandwidth and/or disk transportation radio, and will gain the best performance when the selective radio of semi join is relatively small and the data skew is relatively high.