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。
It is difficult to use the decision tree method to find the sub-optimal solution, not to mention the alternative ranking.
利用传统的决策树方法,无法确定一个次优方案,对所有方案进行排序也很难。
You will find that alternative optimal solutions are possible.
你会发现选择最佳的解决方案是可行的。
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