The query optimizer does not recalculate the profile for tables automatically.
查询优化器不会自动重新计算表的配置文件。
However, if no indexes are available, the query optimizer must use a table scan.
但如果没有索引，则查询优化器必须扫描表。
The query optimizer will try to reduce the number of messages sent to the data source.
查询优化器将尝试减少发送到数据源的消息的数量。
The query optimizer is one of the most important components of a database system.
查询优化器是数据库系统最重要的组件之一。
STEP d: We need to explain the queries to view the access plans chosen by the DB2 query optimizer.
第4步：我们需要对查询进行explain(解释)，以查看DB 2查询优化器所选择的访问计划。
These views include columns containing statistical information that is useful to the query optimizer.
这些视图包括一些包含对查询优化器有用的统计信息的列。
The query optimizer bases query-cost estimates on the number of rows to be retrieved from each table.
查询优化器根据从每个表检索的行数估计查询成本。
Given accurate statistics, the query optimizer generally comes up with correct selectivity estimates.
如果有了准确的统计信息，那么查询优化器一般能够得出正确的选择性估计。
The output of the query optimizer on a federated system is the Federated Query Execution Plan (FQEP).
联邦系统上查询优化器的输出是联邦查询执行计划（FederatedQuery Execution Plan，FQEP）。
During plan generation for the query, the query optimizer communicates with the non-relational wrapper.
在为查询生成计划的过程中，查询优化器与非关系包装器通信。
A new feature of the query optimizer supports a new type of index scan, called an index self-join path.
查询优化器的一项新特性支持一种新的索引扫描，即索引自连接路径。
The query optimizer relies heavily on these statistics — especially card, colcard, high2key and low2key.
查询优化器很大程度上依赖于这些统计信息——尤其是card、colcard、high2key和low2key。
Accurate index information and statistics are fundamental to cost-based decisions in the query optimizer.
准确的索引信息和统计信息是查询优化器中基于成本的决策的基础。
With this feature, the query optimizer can immediately consider the index when determining an access plan.
有了这个特性，查询优化器可以在决定访问计划时立即考虑索引。
DB2 UDB comes with a powerful cost-based query optimizer that determines the best strategy to access data.
DB 2 UDb中包含了一个功能强大基于成本的查询优化器，用于确定访问数据的最佳策略。
An entry is added to the system catalog to indicate to the query optimizer that such a remote index exists.
一个条目被添加到系统编目中，以向查询优化器表明存在那样的一个远程索引。
At the same time query optimizer of database management system is used to guide the optimize process.
同时应用数据库系统的查询分析器来指导优化的过程。
Visual Explain also includes information on the database objects considered and chosen by the query optimizer.
VisualExplain还包括关于查询优化器所考虑和选择的数据库对象的信息。
The query optimizer also tries to reduce the number of messages sent to the data source if the network is slow.
如果网络较慢，查询优化器还尝试减少发送到数据源的消息数量。
The push-down decision is made by the wrapper during the planning phase, while working with the query optimizer.
下推的决定是包装器在计划阶段与查询优化器一起做出的。
Can perform faster with the creation of a keyed logical file containing the keys suggested by the query optimizer?
按照查询优化器建议的键创建逻辑文件能够执行得更快。
The query optimizer USES statistics gathered on tables and indexes when determining the optimal execution plan.
查询优化器使用表和索引的统计信息去决定最优的执行计划。
In general, the query optimizer selects a plan that will return the entire result set in the shortest amount of time.
通常，查询优化器选择将在最短时间内返回整个结果集的计划。
Focus on problem of statistics of query optimizer on update, we design a statistics method based on partition technique.
并针对传统查询优化器对于大规模海量数据统计信息更新不及时的问题，设计了一种基于分区技术的统计方法。
The query optimizer will give priority to an execution plan involving an MQT over a plan that involves access to remote tables.
对于涉及到MQT 的执行计划，并且该 MQT 是涉及远程表访问的计划上的 MQT，查询优化器给予它优先权。
The SQL explain facility provides detailed information about the access plan that the query optimizer chooses for an SQL statement.
SQL解释工具提供查询优化器为 SQL语句所选择的访问计划的有关详细信息。
In the integration server layer, design a query optimizer and research query rewrite, cost estimation model and caches mechanism.
在服务器层设计一个查询优化器，并研究了查询重写和代价估计优化方法以及缓存机制。
Regardless of schema (3nf or Star), the Teradata query optimizer relies on statistics to help it determine the best way to access data.
不管哪种模式(3nf或Star)，Teradata查询优化器依赖于统计信息帮助确定最佳数据访问路径。
This allows the query optimizer to do a better job of analyzing the complex query, as the statistics can now closely reflect the actual cost.
这使得查询优化器可以更有效地分析复杂的查询，因为现在统计信息近似地反映实际成本。
Tuning the Universal Server's query optimizer for particular types of complex data can vastly improve querying speed on those data types.
为特定类型的复杂数据调整万能服务器的查询优化器，能大大提高这些数据类型的查询速度。
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