This short article i have focused on a special field of PHP optimization. It deals with the php.ini.
The php.ini file is the configuration file of PHP. It contains directives and settings, that affect the execution of the PHP script. The possible modifcations, that you can do to increase the speed of execution, are very special. You have to decide which of the settings, that are listed below, seems wise to you and your application. This article is a part of the web-application performance series.
realpath_cache_size & realpath_cache_ttl
PHP uses a realpath-cache to cache the path of include/required-files. This cache was introduced in PHP 5.10 and brought a high improvement of speed into PHP. The default value should be 16K, which is a really good ratio.
The default value since PHP 4.2.0 is set to Off, nevertheless you should convince yourself, that this value isn’t set to On. On the one hand, register_globals are well known as a big security issue and on the other hand PHP creates all variables in $_GET, $_POST, $_COOKIE, $_REQUEST, $_SERVER and $_SESSION in register_globals variables, too. This costs a unnecessary amount of time!
Is always_populate_raw_post_data set to On, PHP fills $HTTP_RAW_POST_DATA with raw data, that comes in with POST. Turn this directive to Off, if you’re not planning something special with it. It saves time and memory.
This directive copies all data into the outdated $HTTP_*_VARS. You can access this data for instance with $_GET. You should turn register_long_arrays to Off to save time and memory.
To tell the webserver which version of PHP is installed, PHP sends an information string to the webserver. Set this directive to Off, to avoid an unnecessary string copy. In addition to that, it is safer to tell just the necessary information and not more.
If you are using your PHP scripts with a webserver, then you don’t need argc (number of command line arguments) and argv (array that contains the command line arguments). Is register_argc_argv set to On, then PHP tries to parse and copy this variables into the symbol table of the script. This takes unnecessary time. Turn it to Off to save time.
The asp_tags directive points out, that the PHP detects also ASP tags like <% and %>. It’s not best practice to use ASP tags in PHP scripts. If you don’t use these tags, you should turn Off the asp_tags directive to save time.