Only when necessary , because repeated queries to the type descriptor filter service can decrease performance 由于对类型说明符筛选服务进行重复查询会降低性能，因此仅在必要时才返回
The default services are all demand - created , so there is no loss in performance for adding them at construction time 默认服务都是按需创建的，因此不会因为在构造时添加它们而降低性能。
Other choices that specify a more complex representation of permission state could slow performance to some degree 指定较复杂的权限状态表示形式的其他选择可能会在某种程度上降低性能。
Property rebuilds the index for the data , adding overhead to your application and decreasing performance 设置rowfilter属性会重新生成数据的索引，从而增加应用程序的系统开销并降低性能。
You should understand both forms because the wrong choice can result in weak security or performance loss 这两种形式的安全检查您都应当了解，因为如果选择不当，则会削弱安全性或降低性能。
However , communication between jvm and native code is generally slow , thus too many jni calls can degrade performance 不过， jvm与本机代码之间的通信通常很慢，因此，太多的jni调用可能会降低性能。
Database resides on disk , the bottleneck from i o operations as data is written to and from disk impairs performance 数据库驻留在磁盘上，因此在将数据写入或写出磁盘时来自i / o操作的瓶颈会降低性能。
Performance is reduced because of the management overhead that is needed to move the data between the application and the data store 由于在应用程序和数据存储区之间移动数据所需的管理开销而降低性能。
Exceptions can cause performance to suffer significantly , so you should avoid using them as a way to control normal program flow 异常会大大地降低性能，所以您应该避免将它们用作控制正常程序流的方式。
After optimized by corresponding method described in this thesis , the efficiency of the encoder is remarkably improved with little performance loss 在并未显著降低性能的前提下，有效的提高了编码器的效率。
