我故意拔掉主机与交换机之间的一根 FC电缆，从而中断其中一条访问路径。
I purposely interrupt one of the access paths by pulling off an FC cable between the host and switch.
查询的访问路径：如何访问这些表？
索引设计对访问路径选择至关重要。
Index design has a critical impact on access path selection.
从而，它能提升可能的访问路径。
选择访问路径的其他影响因素。
描述访问路径最容易的方法是使用示例。
The easiest way to describe access paths is to use an example.
sql语句本身也会影响访问路径选择。
The SQL statement itself also impacts the access path selection.
在执行过程中创建临时的关键访问路径。
请记住，优化器使用编目数据决定访问路径。
Keep in mind that this catalog data is what the optimizer USES to make access path decisions.
它高效，因为索引适合于最佳访问路径的选择。
It is efficient, as the indexes qualify for the choice of excellent access paths.
选择访问路径：DB 2做出什么决策？为什么？
如图1所示，DB 2优化器选择最佳访问路径。
As shown in Figure 1, the DB2 optimizer chooses the best access path.
清单6中的sql语句创建如图6所示的访问路径图。
The SQL statement in Listing 6 creates the access path graph shown in Figure 6.
清单5中的sql语句创建如图5所示的访问路径图。
The SQL statement in Listing 5 creates the access path graph shown in Figure 5.
清单4中的sql语句创建如图4所示的访问路径图。
The SQL statement in Listing 4 creates the access path graph shown in Figure 4.
清单8中的sql语句创建如图8所示的访问路径图。
The SQL statement in Listing 8 creates the access path graph shown in Figure 8.
这些不同的方法就是众所周知的访问路径或访问计划。
These different ways are known as access paths or access plans.
为了查看表描述符，请右键单击访问路径图上的表节点。
To see the table descriptor, right-click the table node in the access path graph.
不一致的统计数据还会误导优化器选择糟糕的访问路径。
The inconsistent statistics may also mislead the optimizer into choosing a bad access path.
本文描述了访问路径的基本概念以及如何解读访问路径图。
This article described the basic concepts of access paths and how to read an access path graph.
假设这是事实，基础访问路径会被认为具有最佳的高可信度。
Assuming this to be the case, the underlying access path is considered optimal with high confidence.
具体表现就是提前执行一些工作，比如确定数据库访问路径。
It does this by performing some work ahead of time, such as determining the database access path.
访问路径图不但描述“操作细节”，而且描述数据如何流动。
An access path graph not only describes the "operational details" of query execution, it also describes how the data flows.
然而，对于此示例则选择了一个不同的访问路径，如图7所示。
However, for this example a different access path is selected, which is shown in Figure 7.
请参考本系列之前的文章，了解更多阅读和理解访问路径的文章。
Refer to the previous article of this series for more information about reading and understanding access paths.
这个简单的步骤可能产生新的访问路径，可能显著改进查询性能。
That simple step could lead to a new access path that might dramatically improve query performance.
因此，其中一条访问路径的中断不会影响从主机发起的存储访问。
So, any interruption to one of the access path does not affect storage access from the host.
清单3中的SQL语句创建如图 3所示的访问路径图
The SQL statement in Listing 3 creates the access path graph shown in Figure 3.
您可以从基础访问路径图中的表节点的表描述符处获得该统计信息。
You can obtain the statistics from the table descriptor of the table node in the underlying access path graph.
为简单起见，本文引用了一种满足sql语句的流行方法作为访问路径。
For simplicity, this article refers to a particular way of satisfying an SQL statement as the access path.
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