定位系统性能瓶颈的时候要多利用数据以及统计信息等资源而不要过多的依赖自己以前积累的经验想当然。因为今天的系统已经变的非常复杂，性能分析的一些浮浅的规则不容易产生。oracle性能改进方法论定义的是一种工作的方法而不是一组权威性的规则。在定位性能瓶颈的时候，最好的规则就是没有规则（With bottleneck detection, the only rule is that there are no rules!The best performance engineers use the data provided and think laterally to determine performance problems.）[@more@]
The Oracle performance improvement method can be applied until performance goals are met or deemed impossible. This process is highly iterative, and it is inevitable that some investigations will be made that have little impact on the performance of the system. It takes time and experience to develop the necessary skills to accurately pinpoint critical bottlenecks in a timely manner. However, prior experience can sometimes work against the experienced engineer who neglects to use the data and statistics available to him. It is this type of behavior that encourages database tuning by myth and folklore. This is a very risky, expensive, and unlikely to succeed method of database tuning.
Today's systems are so different and complex that hard and fast rules for performance analysis cannot be made. In essence, the Oracle performance improvement method defines a way of working, but not a definitive set of rules. With bottleneck detection, the only rule is that there are no rules! The best performance engineers use the data provided and think laterally to determine performance problems
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