1·At each operator in the access plan, the optimizer estimates the cardinality output from the operator.
对于访问计划的每个操作符，优化器将估计该操作符的基数输出。
2·The optimizer calculates and compares the costs of each join method and selects the best one to use when evaluating query execution plans.
当评估查询执行计划时，优化器计算并比较每种连接方法的成本，然后选择要使用的最佳方法。
3·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。
4·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。
5·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。
1·The DB2 optimizer USES these characteristics and restrictions when determining the best way to process a query.
DB 2优化程序使用这些特征和限制来确定处理一个查询的最佳方法。
2·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。
3·What is wrong with the bills table that the optimizer thinks it should sequentially scan the entire table?
账单表出了什么问题，使得优化程序认为需要顺序扫描整个表？
4·The optimizer avoids generating access plans using the hash distinct algorithm if it detects that a low memory situation may occur during query execution.
如果优化程序检测到在查询执行过程中可能会出现内存不足的情况，它将避免使用非重复散列算法生成访问计划。
5·The built-in optimizer allows complete automation in the matching process without the need for manual updates to the reservoir model properties.
内置的优化程序在匹配过程中可以实现完全自动化，而不需要手动更新油藏模型。