caching - Symfony2 bootstrap.php.cache 文件的用途是什么？

Question

我在我们的一个遗留项目中使用 SF2，不是整个框架，而是通过引入我需要的 bundle 和组件。我一直对这些代码行感到好奇:

$loader = require_once __DIR__.'/../app/bootstrap.php.cache';

require_once __DIR__.'/../app/AppKernel.php';
//require_once __DIR__.'/../app/AppCache.php';

$kernel = new AppKernel('prod', false);
$kernel->loadClassCache();

我想知道这个 bootstrap.php.cache 文件的用途是什么，它的用途是什么，它是如何生成的(如果我没有使用 SF2 整个框架)。我以前没有使用过它，也没有问题，但我想知道这是否可以给我带来一些我应该研究的性能提升等。我尝试四处查找，但找不到专门讨论该主题的文档。

Answer 1

To ensure optimal flexibility and code reuse, Symfony2 applications leverage a variety of classes and 3rd party components. But loading all of these classes from separate files on each request can result in some overhead. To reduce this overhead, the Symfony2 Standard Edition provides a script to generate a so-called bootstrap file, consisting of multiple classes definitions in a single file. By including this file (which contains a copy of many of the core classes), Symfony no longer needs to include any of the source files containing those classes. This will reduce disc IO quite a bit.

来源:Use Bootstrap Files .