启用或禁用一个查询执行跟踪。
以下部分概述如何启用查询执行跟踪。
The following section outlines how to enable the Query Execution Trace.
DB2用于查询执行的现有索引的名称。
Names of existing indexes that are used for query execution by db2.
每个连接线程还执行身份验证和查询执行。
Each connection thread also performs authentication and query execution.
DB2未用于查询执行的现有索引的名称
Names of existing indexes that are not used for query execution by DB2
查询执行性能的稳定性。
参数化查询在查询执行之前绑定参数的值。
A parameterized query binds the value of the parameter before the query execution.
本节阐释每个分区特性对查询执行性能的作用。
This section illustrates how each partitioning feature contributes to the performance of query execution.
db 2 batch2-查询执行的改进。
这些可视化包括来自查询执行的基于成本的信息。
These visualizations include cost based information derived from the query execution.
图8 . db 2 batch-查询执行。
TRACEONLY选项禁止显示查询执行结果。
The TRACEONLY option disables the display of query execution results.
启用压缩后，查询执行速度快了近30%，如下所示。
After enabling compression the query executes nearly 30% more quickly, as shown below.
查询执行后，最终结果发送回Web客户机。
After the queries are executed, the final output is sent back to the Web client.
图11 . db 2 batch-查询执行的改进。
在IBMCognos10系统上启用查询执行跟踪。
Enable the Query Execution Trace on the IBM Cognos 10 system.
最后，我们希望判断在这个查询执行期间使用的系统资源总量。
Finally, you may wish to determine how the overall system resources are being used during the execution of this query.
处于查询执行的核心，且可以包含多个不同类型的运行树节点。
The run tree is at the heart of query execution and can consist of many different types of run tree nodes.
直观地说，访问路径是查询执行的程序说明，其包括三个组件。
Intuitively, an access path is a procedural description of query execution that consists of three components.
用于定义在查询执行期间空间索引的搜索范围的范围生成器函数。
Range producer function to define the search ranges for the spatial index during query execution.
如您所见，查询执行了三次，平均运行时间大约是307秒，非常慢。
As you can see, the query was executed three times, and the average elapsed time is about 307 seconds, which is very slow.
属性查询通常比图表查询执行速度快，返回的信息相对较少。
Property queries are typically faster and return less information than graph queries.
然而，为了获得最佳的开销评估值，优化器需要获得查询执行时使用的值。
However, in order to get the best cost estimate, the optimizer needs the values that will be used when the query executes.
在图13中看到，查询执行了两个排序，花费的时间少于12秒。
In Figure 13, you see that the query performed two sorts and spent less than 12 seconds to complete.
显示只需要一次编译，具有不同值的同一查询执行了 73次。
show that only one compilation was required, and that the same query with different values is executed 73 times.
RETURN操作符将完成查询执行，并将查型结果返回到API。
The return operator completes the query execution and returns the query result to the API.
该过程将创建下列表、存储建议以及与查询执行过程中碰到的谓词有关的信息。
This procedure will create the following tables that store recommendations, and information about the predicates encountered during query execution.
了解数据流很重要，因为就查询执行的查询性能方面来说，这是最有影响力的因素。
Understanding data flow is important because it is the most influential factor in terms of the query performance aspect of query execution.
所有SQL比较、SQL查询执行以及SQL类型转换都必须在数据库代码页中进行。
All SQL comparisons, SQL query execution, and SQL casting takes place in the database code page.
这个基础的例子显示了JPA 1.0中的查询执行模型的以下关键方面。
This basic example shows the following key aspects of the query-execution model in JPA 1.0.
应用推荐