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？
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.
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.
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.
不要指定表单的访问路径可以避免在发布表单到服务器时出错。
Do not specify an alternative path to the form. Doing so causes an error that prevents you from publishing the form to the server.
如本文开头所提到的，统计数据是优化器作出关于访问路径的决策的基础。
As was mentioned at the beginning of this article, database statistics are the facts on which the optimizer makes decisions about access plans.
这种类型的访问路径被称为使用复合排序的嵌套循环联接(NLJOIN)。
This type of access path is referred to as a nested loop join (NLJOIN) with sort composite.
因为其是一个唯一索引扫描，所以在访问路径图中不显示FETCH或表节点。
There is no FETCH or table node shown in the access path graph because it is an index-only scan.
数据从下往上流动(如访问路径图所示)并通过访问路径图上的操作节点处理。
Data flows from the bottom up (as displayed in the graph) and is processed by operation nodes in the access path graph.
因此，如果优化器的估计是准确的，则此访问路径应该是一个非常有效的访问路径。
Therefore, if the optimizer's estimate is accurate, this access path should be a very efficient access path.
然后，我故意拔掉主机与交换机之间的一根 FC电缆，以中断其中一条访问路径。
Then I purposely interrupt one of the access paths by pulling off an FC cable between the host and switch.
这就说明我可能有一个低效的访问路径，DB 2读取的数据比应该读取的数据更多。
This tells me that I may have an inefficient access path, where DB2 reads more data than it should.
访问计划描述访问路径，这些路径是DB 2优化器为sql语句访问数据而选择的。
Access plan describes the access path that the DB2 optimizer has chosen for accessing data for an SQL statement.
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