Cache-Based Aggregate Query Shipping: An Efficient Scheme of Distributed OLAP Query Processing

Our study introduces a novel distributed query plan refinement phase in an enhanced architecture of distributed query processing engine(DQPE) . Query plan refinement generates potentially efficient distributed query plan by reusable aggregate query shipping(RAQS) approach. The approach improves response time at the cost of pre-processing time. If the overheads could not be compensated by query results reusage,RAQS is no more favorable. Therefore a global cost estimation model is employed to get proper operators:RR Agg,R Agg,or R Scan. For the purpose of reusing results of queries with aggregate function in distributed query processing,a multi-level hybrid view caching(HVC) scheme is introduced. The scheme retains the advantages of partial match and aggregate query results caching. By our solution,evaluations with distributed TPC-H queries show significant improvement on average response time.