optimizer
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英
例句
Due to the interplay of these diverse independent factors, in rare instances, the optimizer might select less than optimal execution plans.
在这些不同的独立因素的相互作用下，优化器可能会选择不太优化的执行计划。
Ideally, the optimizer would identify the most efficient access plan possible, but this goal is often impractical.
在理想情况下，优化程序将尽可能地找出最为高效的访问计划，但这一目标通常是不切实际的。
Note, however, that the optimizer is often unable to precisely estimate a query's cost, so expect there to be differences.
但是，请注意，优化程序通常无法精确地预计查询的成本，因此应该会存在差异。
The output of the optimizer is a query execution plan, sometimes referred to as a query plan or just a plan.
优化器的输出称为“查询执行计划”，有时也称为“查询计划”或直接称为“计划”。
You can use the REWRITE function without the ANSI argument to help understand how the optimizer generated the access plan for a given query.
使用REWRITE函数时可以不带ANSI参数，这样可以帮助理解优化程序是如何生成给定查询的访问计划的。
No degree of query optimizer intelligence can eliminate the resource cost of these constructs when compared to a less complex query.
与不太复杂的查询相比，查询优化器的智能水平无法消除这些构造的资源开销。
The optimizer's estimate could be very close to the actual value as long as the data distribution has not changed since the last RUNSTATS.
只要数据分布自上一次RUNSTATS以后没有改变，则优化器的估计可能非常接近实际值。
Further, the solidDB query optimizer recognizes the different nature of the in-memory tables by estimating execution costs in a new way.
而且，solidDB查询优化器通过以一种新的方式估计执行成本，判别内存中的表的不同性质。
It is possible that the query optimizer might have generated a remote statement that hits the remote server's limitation on performance.
查询优化器有可能生成与远程服务器的性能限制有冲突的远程语句。
Predicates with concrete values are important for the optimizer to be able to use available distribution statistics.
为使优化器能够使用可用的分布统计信息，带有具体值的谓词极为重要。
If the execution plan problems cannot be avoided, guidelines can be used to affect the optimizer plan to mitigate the performance problems.
如果无法避免执行计划中出现的问题，那么可以使用准则来影响优化器计划，从而解决性能问题。
The optimizer uses MAGIC values as a last resort when it is unable to accurately predict the selectivity of a predicate .
当优化程序不能准确判定一个谓词的选择性时，它的最后一个手段就是利用MAGIC值。
Many customers new to Informix do not realize they must update statistics, and see poor performance due to the lack of optimizer statistics.
许多Informix新客户没有认识到他们必须更新统计数据，因此由于缺少最新的优化器统计数据，他们的数据库性能很差。
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。
Up-to-date statistics allow the optimizer to accurately assess the cost of different query plans, and choose a high-quality plan.
最新的统计信息允许优化器准确地估计不同查询计划的开销，并选择高质量的计划。
If the best indexes do not exist, the query optimizer generates a suboptimal query plan, but still stores information about these indexes.
如果不存在最佳索引，则查询优化器将生成非最佳查询计划，但会存储有关这些缺失的最佳索引的信息。
The optimizer depends on accurate cardinality estimates to properly compute the cost of each query access plan considered.
优化器凭借精确的基数估计值来准确计算出每一个待定查询访问计划的成本。
db2exfmt is typically used for comprehensive performance analysis, as it provides the most optimizer information.
db2exfmt通常用于广泛的性能分析，因为它提供了大部分优化器信息。
Information returned by sys. Dm_db_missing_index_details is updated when a query is optimized by the query optimizer, and is not persisted.
由sys.dm_db_missing_index_details返回的信息会在查询优化器优化查询时更新，因而不是会持久化的。
Specifies the name or ID of the indexes to be used by the query optimizer when it processes the statement.
指定查询优化器处理语句时要使用的索引的名称或ID。
Instead, the optimizer gathers up-to-date statistics on every database table referenced in a query.
相反，优化器将对查询中引用的每个数据库表收集最新的统计数据。
Think of the optimizer as an explorer waiting to navigate a mountain represented by the data in the system.
可以将优化器视为一个勘探器，正在系统中的数据所代表的大山中进行定位。
Unlike other heart-failure devices , the Optimizer works by strengthening the pumping force of the heart.
和其他治疗心衰装置不同的是，优化装置增强心脏泵血能力。
You can access the results and reports of various statistics within Google Website Optimizer to see which variant is the most effective.
你可以通过查看google网页优化工具的统计结果和报告，来判断哪一种页面变化能最有效率地提升转化率。
WideVine was a video optimizer and one of the last major independent digital rights managers.
WideVine是一家视频优化公司，也是最后一批主要的独立数字版权管理者之一。
An estimate source of Guess indicates that the optimizer has no selectivity information to use .
如果查询被确定为是简单查询，则不会显示选择性统计信息，这样将绕过优化程序。
Almost every major database today uses some method of updating catalog statistics to provide the best information possible to its optimizer.
现在，几乎所有重要数据库都使用某种方法来更新目录统计信息，以便为其优化器提供可能的最佳信息。
The view does not have to be referenced in the query for the optimizer to consider that view for a substitution.
要使优化器考虑将该视图作为替换，并不需要在查询中引用该视图。
WebSphere Federation Server uses its cost-based optimizer to determine the most efficient means of resolving the multi-source query.
WebSphereFederationServer使用它的基于成本的优化器决定执行多源查询的最有效的方式。
The query optimizer, in consultation with the wrapper, determines how the data is to be accessed.
查询优化器与包装器一道决定如何访问数据。
This set is input to the cost-based optimizer that decides whether to use any of the eligible indexes or not.
将该组索引输入到基于成本的优化器，这个优化器决定是否使用任何合适的索引。
If such a plan is not possible , the query optimizer returns an error instead of deferring error detection to query execution .
如果不能使用这样的计划，查询优化器将返回错误而不是延迟对查询执行的错误检测。
The optimizer will compare the cost of each method to determine the best one to use.
优化器将比较每种方法的成本，确定使用最好的一种。
Updating index statistics to make sure the query optimizer has up-to-date information about the distribution of data values in the tables.
更新索引统计信息，确保查询优化器含有关于表中数据值分布的最新信息。
Application developers have to be careful, as in certain situations distribution statistics are important for the DB2 optimizer.
应用程序开发人员必须小心谨慎，因为在某些情况下分布统计信息对于DB2优化器来说非常重要。
If you do not implement UPDATE STATISTICS, the optimizer has inaccurate data to determine access paths.
如果没有运行UPDATESTATISTICS，则优化器只能使用不准确的数据来确定访问路径。
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。
Tuning such an environment by only analyzing the optimizer plans is not feasible due to the quantity of produced plans.
由于所产生的计划数量太多，仅通过分析优化器计划来调优该环境是不可行的。
When cursors generate a keyset for a result set, the query optimizer estimates the number of rows that will be returned for that result set.
游标为某个结果集生成键集时，查询优化器将估计为该结果集返回的行数。
The total cost to the query optimizer for executing this operation and all operations preceding it in the same subtree.
查询优化器执行此操作及同一子树内位于此操作之前的所有操作的总开销。
