基于分布式系统OceanBase的并行连接

摘要

With the rapid growth of application data and the continued development of distributed database systems,data storage in physical independent nodes has become a trend.In this trend,when the application needs to perform complex join queries,it inevitably generates a lot of network traffic.Therefore,improving the efficiency of join query in distributed system is a hot topic.Based on the analysis of the nested loop join,Hash join,semi-join in the OceanBase,this paper puts forward the optimization idea of using hardware resources reasonably and using multithread to execute join operations in parallel.We implement experiment on OceanBase with nested loop join algorithm,Hash join algorithm,semi-join algorithm respectively.The experimental results confirm that the efficiency of join algorithm is positively related to parallelism in a certain number of threads.%随着应用数据的飞速增长以及分布式数据库系统的不断涌现,数据存储在物理独立的节点已经成为一种趋势.在这种情况下,当应用需要进行复杂join查询时,就会不可避免地产生非常多的网络传输代价.所以,如何提高分布式系统中join查询的效率成为研究热点.本文在分析分布式数据库系统OceanBase执行nested loop join、Hash join、semi-join等算法的基础上,提出了合理利用硬件资源采用多线程并行执行join操作的优化思想,并在OceanBase数据库中分别对nested loop join、Hash join、semi-join等算法进行了并行改造.实验结果表明,在一定线程数内join算法执行效率与并行度呈正相关.