【摘要】 随着oracle版本的不断地改进,传统的基于规则的优化器rbo逐渐被基于成本的优化器cbo代替。Cbo优化器是一种基于成本的优化器技术,而优化器性能的高低直接关系到数据库性能的好坏,因此对cbo优化器的研究就显得非常重要了。该文围绕着cbo优化器的概念、计算原理,全面的介绍了cbo优化器的用途和两个重要的参数成本和基数的计算过程。同时,文章对优化器的不足之处提出了优化方案并通过实验数据验证了优化方法。更多还原

【Abstract】 With the version of oracle continuously improve,the traditional rbo optimizer has been replaced by the cbo optimizer.The Cbo optimizer is a cost-based optimizer technology.The level of Optimize performance is directly related to the quality of database performance,so the study of the Cbo optimizer is very important.This article revolves around the concept of the cbo optimizer,calculation principle,comprehensively introduces the cbo optimizer uses and two important parameters of the cost and cardinality.At the same time,the article puts forward optimization method which is verified by experimental data.更多还原