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...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 globM 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.展开更多
基金partially supported by the National Basic Research 973 Program of China under Grant No. 2005CB321807the National High Technology Rresearch and Development 863 Program of China under Grant Nos. 2006AA01A106 and 2006AA04Z158.
文摘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 globM 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.
