Find the top join node in a query plan.
查找一个查询计划中的顶级连接节点。
This query plan shows full table scans.
该查询计划显示了全表扫描。
This query plan shows a full table scan.
该查询计划显示了一个全表扫描。
A query plan is a sequence of operators.
一个查询计划是一个操作符序列。
Collect all tables referenced in the query plan.
集合查询计划中引用的所有表。
Use SQL directives to effect the query plan.
使用SQL指令实现查询计划。
This query plan shows the use of a functional index.
该查询计划展示了函数索引的使用。
This query plan shows an index scan using our functional index.
该查询计划显示索引扫描使用了函数索引。
Devising new paradigms for query evaluation and query plan migration.
设计新的查询评估和查询计划变动的范例。
The following section outlines how to enable the Query Plan Trace.
以下部分概述如何启用查询规划跟踪。
Below is an example of how a query plan would look like for the query.
通过下面的例子可以看到查询的查询计划是什么样子？
Static queries have already been parsed, and had a query plan generated.
静态查询已经经过解析，并生成了查询计划。
A query plan allocation model based on market mechanism for SDGDQA.
基于市场机制的查询计划分配模型。
set explain on directs IDS to generate a file that shows the query plan.
setexplainon 指示IDS生成显示查询计划的文件。
When a static query is executed, the previously computed query plan is used.
当执行静态查询时，会使用以前生成的查询计划。
Hence, the need for statistical views arises in query plan optimization.
因此，在进行查询计划优化时，就需要使用统计视图。
The optimizer USES the following system catalog information as it creates a query plan.
当优化器创建查询计划时，它将使用下列系统目录信息。
The value ANY allows the optimizer to determine the number of ATQs for a given query plan.
值ANY允许优化器决定一个给定查询计划的 ATQ的数量。
This query plan uses hash join for each join between the fact table and a dimension table.
这个查询对每个事实表和维度表之间的连接使用散列连接。
We can then examine the equivalent symbolic tree representation of this query plan in Figure 1.
随后，我们可以查看图1，其中展示了这个查询计划的等效符号树表示形式。
It's a right-deep query plan such that for each hash join, the build table is a small dimension table.
每个散列连接都是右深查询，构建的表是一个小的维度表。
The query plan information shown in the following examples is taken from the sqexplain.out file for this query.
以下示例中显示的查询计划信息来自这个查询的sqexplain.out文件。
Conceptually, rows of relational data (tuples) flow through the operation nodes in the query plan from bottom to top.
从概念上来说，关系数据行(元组)按照自下向上的方式流过查询计划中的操作节点。
In order to realize performance gains from this complicated SQL statement DB2 selects a very sophisticated query plan.
为了从这个复杂的sql语句中赚取性能，DB 2选择一个非常精妙的查询计划。
As this query plan shows, keys from more than one hash table build can be pushed down to filter rows of the fact table.
如这个查询计划所示，不止一个散列表的键可以被下推来过滤事实表的行。
This method cuts down query plan search space greatly, thus ensures the quality of parallel query execution plans.
这种优化方法大大地缩减了查询执行计划空间，确保了并行查询执行计划的优化性。
Enables or disables query plan tracing, also known as a plan tree, which captures the transformation process of a query.
启用或禁用查询规划跟踪，也称为规划树，它捕获一个查询的转换流程。
After the optimizer has done its work, the compiler converts the query plan into executable code segments called snippets.
优化器完成工作后，编译器将把查询计划转换为可执行的代码段，称为snippet。
This command updates the statistics in the system catalogs that the optimizer USES to determine the lowest-cost query plan.
此命令更新了系统目录中的统计数据，优化程序使用这些数据来确定成本最低的查询计划。
To ensure that the optimizer selects the best query plan, it is important to keep internal statistics current and accurate.
为了确保优化器选择最佳的查询计划，使内部统计数据保持为最新并且最准确的十分重要。
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