Realpath_cache_size default parameter settings are too low (16k).
In the windows and Polish language assessed following be at least a 32k or 64k.
otherwise appache sometimes locks up (especially when using IE).
(PHP 5 >= 5.3.2, PHP 7)
realpath_cache_size — 获取真实路径缓冲区的大小
获取真实路径缓存区大小在内存中的使用量。
返回真实路径缓存区使用内存的用量。
Example #1 realpath_cache_size() example
<?php
var_dump(realpath_cache_size());
?>
以上例程的输出类似于：
int(412)
Realpath_cache_size default parameter settings are too low (16k).
In the windows and Polish language assessed following be at least a 32k or 64k.
otherwise appache sometimes locks up (especially when using IE).
"realpath_cache_size" is used by PHP to cache the real file system paths of filenames referenced instead of looking them up each time. Every time you perform any of the various file functions or include/require a file and use a relative path, PHP has to look up where that file really exists. PHP caches those values so it doesn't have to search the current working directory and include_path for the file you are working on.
If your website uses lots of relative path files, think about increasing this value. What value is required can be better estimated after monitoring by how fast the cache fills using realpath_cache_size() after restarting. Its contents can be viewed using realpath_cache_get().
Note that the realpath cache is not used if either safe_mode is on or an open_basedir restriction is in effect.
This is having a huge performance effect, causing lots of calls to lstat.
A bugreport has already been filed at http://bugs.php.net/bug.php?id=52312