optimizer

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。