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首页> 外文期刊>International Journal of Geographical Information Science >Generic cumulative annular bucket histogram for spatial selectivity estimation of spatial database management system
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Generic cumulative annular bucket histogram for spatial selectivity estimation of spatial database management system

机译：空间数据库管理系统空间选择性估计的通用累积环形桶直方图

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摘要

Selectivity estimation is crucial to query optimizers in choosing an optimal execution plan in a given spatial query, and there has been a great deal of focus on how to achieve good selectivity estimation for finer spatial selection operators. Equally crucial to this is understanding how to produce an updated spatial histogram. With this in mind, we used a cumulative annular bucket histogram (AB histogram), which not only accurately estimates the selectivity of a spatial selection or a spatial join operation with finer operators but also provides an updated spatial histogram to estimate the selectivity of subsequent spatial operations in a multi-level spatial query plan. A basic unit of AB histogram stores the number of minimum bounding rectangles whose lower left points and upper right points are located in specific rectangular regions. According to the basic units of a cumulative AB histogram, we can find out the selectivity of a spatial selection with a number of different finer operators. When it comes to spatial join operations, a relationship between two cumulative AB histograms can be translated into a relationship between one histogram and numerous query windows from the other histogram. Furthermore, an updated cumulative AB histogram can be simultaneously built into the process of selectivity calculation, making it possible to achieve both selectivity and an updated histogram of spatial join; its implementation made in the optimizer facility (OPF) of INGRES9.2. To highlight the performance of a cumulative AB histogram, several experiments have been conducted, with results showing that the cumulative AB histogram not only supports the selectivity estimation of spatial selection and spatial join with 'Disjoint', 'Intersect', 'Within', 'Contains', 'Crosses' and 'Overlap' operators but also supports the generation of an updated histogram. This indicates that Ingres would do better to find a query plan with low-execution costs.
机译：选择性估计对于查询优化器在给定空间查询中选择最佳执行计划至关重要，而对于如何为更精细的空间选择算子实现良好的选择性估计，已经有很多关注。同样重要的是，了解如何生成更新的空间直方图。考虑到这一点，我们使用了累积环形桶直方图（AB直方图），它不仅可以准确地估计空间选择的选择性或使用更精细的运算符进行空间合并操作，还可以提供更新的空间直方图来估计后续空间的选择性多级空间查询计划中的操作。 AB直方图的基本单位存储左下角点和右上角点位于特定矩形区域中的最小边界矩形的数量。根据累积AB直方图的基本单位，我们可以找到具有许多不同的精细算子的空间选择的选择性。关于空间合并操作，可以将两个累积AB直方图之间的关系转换为一个直方图和来自另一个直方图的多个查询窗口之间的关系。此外，可以在选择性计算过程中同时构建更新的累积AB直方图，从而可以实现选择性和空间连接的更新直方图。它的实现是在INGRES9.2的优化程序工具（OPF）中完成的。为了突出累积AB直方图的性能，已进行了一些实验，结果表明，累积AB直方图不仅支持空间选择的选择性估计，还支持“不相交”，“相交”，“在内部”，“包含“”，“交叉”和“重叠”运算符，但也支持生成更新的直方图。这表明Ingres会更好地找到执行成本较低的查询计划。

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    Changxiu Cheng; Xiaomei Song; Chenghu Zhou;

  • 作者单位

    State Key Laboratory of Resources and Environmental Information Systems, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing,PR China;

    State Key Laboratory of Resources and Environmental Information Systems, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing,PR China;

    State Key Laboratory of Resources and Environmental Information Systems, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing,PR China;

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  • 原文格式 PDF
  • 正文语种 eng
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  • 关键词

    selectivity estimation; cumulative AB histogram; annular bucket; spatial selection; spatial join;

    机译：选择性估计;累积AB直方图;环形桶空间选择;空间连接;

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