Towards a Science of Database Systems

迈向数据库系统科学

• 批准号: 0639106
• 负责人: Richard Snodgrass
• 金额: --
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0639106&HistoricalAwards=false
• 关键词: Towards; Science; Database; Systems

IIS-0639106Richard T. Snodgrass [e-mail] of ArizonaTowards a Science of Database SystemsThis research takes a scientifically rigorous approach to an area previouslydominated by the engineering perspective, that of database queryoptimization. The goal is to understand cost-based query optimizers as ageneral class of computational artifacts, to develop insights and ultimatelywith predictive theories about how such optimizers behave.The research focuses on one aspect, that of cardinality estimation. Indetermining the optimal query evaluation plan for a submitted query, theoptimizer estimates the size of the output produced by each operator of eachcandidate plan. An established DBMS has been observed exhibiting "flutter,"in which the query evaluation plans jump around or even alternate back andforth as inevitable cardinality estimate inaccuracies increase. This projectevaluates the theory that the flutter arises out of unanticipatedinteractions between components of the optimizer. The prevalence of flutterwill be examined across this range of DBMSes, to see if that prevalence(measured as percentage of queries exhibiting flutter) is positivelycorrelated to measures of optimizer complexity.In terms of broader impacts, this research studies a previously unknownphenomenon of cost-based query optimizers, offering a scientific rationalefor new architectures for query optimization that explicitly take intoaccount uncertainty. In doing so, it introduces a new perspective (science),adding to the existing mathematical and engineering perspectives now usedprominently in database research, helping to realize Herbert Simon's visionof "sciences of the artificial." The results will be disseminated via theproject Web site http://www.cs.arizona.edu/soc/sodb.

IIS-0639106Richard T. Snodgrass [e-mail] 亚利桑那大学走向数据库系统科学这项研究采用了科学严谨的方法来研究以前由工程观点主导的领域，即数据库查询优化领域。 目标是将基于成本的查询优化器理解为一类通用的计算工件，以深入了解并最终获得有关此类优化器行为的预测理论。该研究重点关注一个方面，即基数估计。在确定提交的查询的最佳查询评估计划时，优化器估计每个候选计划的每个运算符产生的输出的大小。据观察，已建立的 DBMS 表现出“抖动”，其中查询评估计划随着不可避免的基数估计不准确度的增加而跳跃甚至来回交替。该项目评估了以下理论：抖动是由优化器组件之间的意外交互引起的。 我们将在这一系列 DBMS 中检查颤动的流行程度，以查看该流行程度（以表现出颤动的查询的百分比来衡量）是否与优化器复杂性的度量呈正相关。就更广泛的影响而言，本研究研究了一种以前未知的基于成本的现象查询优化器，为明确考虑不确定性的查询优化新架构提供科学原理。在此过程中，它引入了一个新的视角（科学），补充了目前在数据库研究中广泛使用的现有数学和工程视角，有助于实现赫伯特·西蒙的“人工科学”愿景。结果将通过项目网站 http://www.cs.arizona.edu/soc/sodb 传播。