公开(公告)号：US20150234888A1

公开(公告)日：2015-08-20

申请号：US14183409

申请日：2014-02-18

Applicant: Oracle International Corporation

Inventor： Rafi Ahmed ,  Nirav Vyas ,  Mohamed Zait

IPC: G06F17/30

CPC classification number: G06F17/30395 ,  G06F17/30451

Abstract: Methods, stored instructions, and computer systems are described for selecting an OR-expansion state of a query. A query processor accesses a certain query and a control parameter. The certain query comprises disjunctive predicates, and the control parameter indicates a certain procedure of a plurality of alternative stored procedures for expanding queries comprising disjunctive predicates into semantically equivalent candidate queries comprising combinations of subqueries. Based at least in part on the control parameter, the query processor selects the certain procedure to expand the certain query into one or more certain semantically equivalent candidate queries, each comprising a different combination of two or more subqueries. The query processor causes cost-based evaluation of subject queries, including the certain query and the one or more certain semantically equivalent candidate queries. The query processor then selects a query of the subject queries for execution or for further evaluation or transformation.

Abstract translation: 描述了用于选择查询的扩展状态的方法，存储的指令和计算机系统。 查询处理器访问某个查询和控制参数。 该特定查询包括分离谓词，并且控制参数指示用于将包括分离谓词的查询扩展到包括子查询的组合的语义等价候选查询的多个备选存储过程的某个过程。 至少部分地基于控制参数，查询处理器选择某个过程以将特定查询扩展到一个或多个特定语义上等同的候选查询中，每个候选查询包括两个或多个子查询的不同组合。 查询处理器对主题查询进行基于成本的评估，包括特定查询和一个或多个特定语义上等效的候选查询。 然后，查询处理器选择主题查询的查询以供执行或用于进一步的评估或变换。