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EFFICIENT EVALUATION OF QUERIES WITH MULTIPLE PREDICATE EXPRESSIONS
EFFICIENT EVALUATION OF QUERIES WITH MULTIPLE PREDICATE EXPRESSIONS
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机译:具有多个预测表达的查询的有效评估
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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.
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