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EFFICIENT EVALUATION OF QUERIES WITH MULTIPLE PREDICATE EXPRESSIONS

机译:具有多个预测表达的查询的有效评估

摘要

Techniques related to efficient evaluation of queries with multiple predicate expressions are disclosed. A first predicate expression (PE) is evaluated against a plurality of rows in a first column vector (CV) to determine that a subset of rows does not satisfy the first PE. The subset comprises less than all of the plurality of rows. When a query specifies the first PE in conjunction with a second PE, a selectivity of the first PE is determined. If the selectivity meets a threshold, the second PE is evaluated against all of the plurality of rows in a second CV. If the selectivity does not meet the threshold, the second PE is evaluated against only the subset of rows in the second CV. When a query specifies the first PE in disjunction with the second PE, the second PE may be evaluated against only the subset of rows in the second CV.
机译:公开了与具有多个谓词表达的查询的有效评估有关的技术。针对第一列向量(CV)中的多行评估第一谓词表达式(PE),以确定行的子集不满足第一PE。该子集包括少于所有的所有行。当查询指定与第二PE结合的第一PE时,确定第一PE的选择性。如果选择性满足阈值,则针对第二CV中的所有多行评估第二PE。如果选择性不满足阈值,则仅针对第二CV中的行子集评估第二PE。当查询指定第一PE与第二PE分开时,可以仅针对第二CV中的行子集评估第二PE。

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