The optimizer relies on statistics to properly cost alternative query execution plans (QEPs) and choose the most optimal plan.
优化器是依靠统计信息来计算可选查询执行计划（QEP）的开销，同时选择出最优的计划。
A query plan ideally is an optimal plan to execute the given query - that is, it determines the most efficient way to fetch the data.
理想情况下，查询计划是执行给定查询的最佳计划—也就是说，它会确定抓取数据的最佳方式。
The many complex factors and the dynamic nature of data means that an optimal plan evaluation is often a complex process indeed for any database system.
这么多复杂的因素，再加上数据本身的动态性，使得最佳计划的评估对于任何数据库系统而言通常都是一个复杂的过程。
So, the accuracy of getting an optimal plan is entirely dependant on the up-to-date statistical information about the database objects involved in the query.
因此，获得最佳计划的准确性完全取决于关于查询中所涉及的数据库对象的最新统计信息。
With this model, an optimal plan for monthly local allocation and transportation of grain can be compiled on a microcomputer, and its economic efficiency is quite remarkable.
运用该模型可以在微型计算机上确定区域月粮食最优调运计划，经济效益十分显著。
Those models can be references of choosing optimal plan of design about energy efficient residential buildings.
分析模型可供节能住宅设计方案优选时参考。
The results show that the problem of selecting the optimal plan in multi-target orthogonal test design can be solved very well.
结果表明方法能够很好地解决多指标正交试验设计中最优方案的选择问题。
The method can also be adopted in other areas and various engineering projects as well as the optimal plan management of industrial enterprises.
指出该方法也适用于其它各类工作、工程项目以及对工矿企业实施优化的计划管理。
The test shows that the optimal plan worked out by the method presented here has been proved far superior economically to that by the conventional method.
经实践检验，用所提方法制定的优化调度方案较常规方案更具有明显的经济效果。
The model first generates judge-array based on fuzzy optimal theory; and latter determines the optimal plan with the entropy weight decision-making method.
该模型首先根据模糊优选理论生成判断矩阵，后用熵权决策法确定优选方案。
The setting principle of bureau data and optimal plan in telecommunication network are introduced, based on the operating condition of SPC and the network problems.
针对广铁程控交换机的现状和网络存在的问题，提出局数据的设置原则和网络优化方案。
For single operating parameter units, secant method coupled with a unit simulator is used to search feasible operating conditions implementing the quasi-optimal plan.
对于单操作参数装置，利用正割法搜索实现拟最优计划的可行操作条件。
Finally the activity of VE is to summarize and evaluate the situation of the optimal plan, including economic benefit evaluation of enterprise and social effect evaluation.
价值工程活动的最后是对优选方案实施的情况进行总结评价，包括企业经济效益评价和社会效果评价。
Finally the activity of VE is to summarize and evaluate the situation of the optimal plan, including economic benefit evaluation of enterprise and social effect evaluation.
价值工程活动的最后是对优选方案实施的情况进行总结评价，包括企业经济效益评价和社会效果评价。
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