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首页> 外文会议>Database and Expert Systems Applications; Lecture Notes in Computer Science; 4080 >Truly Adaptive Optimization: The Basic Ideas
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Truly Adaptive Optimization: The Basic Ideas

机译：真正的自适应优化：基本思想

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摘要

A new approach to query optimization, truly adaptive optimization (TAO), is presented. TAO is a general optimization strategy and is composed of three elements: 1. a fast solution space search algorithm, derived from A~*, which uses an informed heuristic lookahead; 2. a relaxation technique which allows to specify a tolerance on the quality of the resulting query execution plan; 3. a paradigm to prove the suboptimality of search subspaces. Non-procedural pruning rules can be used to describe specific problem knowledge, and can be easily added to the optimizer, as the specific problem becomes better understood. The main contribution over previous research is the use of relaxation techniques and that TAO provides a unifying framework for query optimization problems, which models a complexity continuum going from fast heuristic searches to exponential optimal searches while guaranteeing a selected plan quality. In addition, problem knowledge can be exploited to speed the search up. As a preliminary example, the method is applied to query optimization for databases distributed over a broadcast network. Simulation results are reported.
机译：提出了一种新的查询优化方法，即真正的自适应优化（TAO）。 TAO是一种通用的优化策略，它由三个要素组成：1.一种从A〜*派生的快速求解空间搜索算法，该算法使用了明智的启发式先行技术； 2.一种松弛技术，其允许指定对所产生的查询执行计划的质量的容忍度； 3.证明搜索子空间的次优性的范例。非过程修剪规则可以用来描述特定的问题知识，并且可以随着对特定问题的更好理解而轻松地将其添加到优化器中。对先前研究的主要贡献是使用了松弛技术，并且TAO为查询优化问题提供了统一的框架，该框架对复杂性连续体进行建模，从快速启发式搜索到指数最佳搜索，同时保证了选定计划的质量。此外，可以利用问题知识来加快搜索速度。作为一个初步的例子，该方法被应用于对在广播网络上分布的数据库的查询优化。报告了仿真结果。

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