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Database System with Methodology for Distributing Query Optimization Effort Over Large Search Spaces
Database System with Methodology for Distributing Query Optimization Effort Over Large Search Spaces
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机译:具有用于在大型搜索空间上分配查询优化工作量的方法的数据库系统
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摘要
In a database system, a method for optimization of a query is described. When a query is received which requests data from a database, a plurality of plans which can be used for obtaining data requested by the query are enumerated. A search tree is created based upon these plans, with nodes of the search tree representing segments of the plans. A limited number of nodes of the search tree are selected for evaluation to limit the effort spent on query optimization. A complete plan for execution of the query is generated by evaluating the selected nodes of the search tree and, if the evaluation determines that a given node is more favorable than comparable nodes previously evaluated, retaining the given node as part of the complete plan.
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