Handling Estimation Inaccuracy in Query Optimization

摘要：

　　Cost-based Optimizers choose query execution plans using a cost model.The latter relies on the accuracy of estimated statistics.Unfortunately,compile-time estimates often differ significantly from runtime values,leading to a suboptimal plan choices.In this paper,we propose a compile-time strategy,wherein the optimization process is fully aware of the estimation inaccuracy.This is ensured by the use of intervals of estimates rather than single-point estimates of error-prone parameters.These intervals serve to identify plans that provide stable performance in several run-time conditions,so called robust.Our strategy relies on a probabilistic approach to decide which plan to choose to start the execution.Our experiments show that our proposal allows a considerable improvement of the ability of a query optimizer to produce a robust execution plan in case of large estimation errors.

关键词： Query optimization Robust plans Estimation errors

作者: Chiraz Moumen Franck Morvan Abdelkader Hameurlain

作者单位: IRIT Laboratory,Paul Sabatier University,118 Route de Narbonne,31062 Toulouse Cedex 9,France

会议类型: 国际会议

会议名称: International Asia-Pacific Web Conference(第18届国际亚太互联网大会)

会议地点: 苏州

会议语种:英文

页码: 355-367

在线出版日期: 2016-09-23（万方平台首次上网日期，不代表论文的发表时间）