composer-php - Composer 转储自动加载 - 命令

Question

我不明白composer dump-autoload命令的描述:

If you need to update the autoloader because of new classes in a classmap package for example, you can use "dump-autoload" to do that without having to go through an install or update.
Additionally, it can dump an optimized autoloader that converts PSR-0/4 packages into classmap ones for performance reasons. In large applications with many classes, the autoloader can take up a substantial portion of every request's time. Using classmaps for everything is less convenient in development, but using this option you can still use PSR-0/4 for convenience and classmaps for performance. 

为什么说 dump ... for performance reasons ？为什么要放弃优化的装载机？是“转储”还是“出于性能原因转换”？

如果它是“为了性能而倾销”，为什么它会说 classmaps for performance ？

如果它是“为性能而转换”，为什么要丢弃自动加载器？

我很困惑。

Answer 1

它转储自动加载器使用的类映射。这样，自动加载器不需要通过文件系统搜索来找到正确的文件，它已经知道该文件。这将节省时间。