If you have seen an error like “Fatal Error: PHP Allowed Memory Size Exhausted” in apache logs or in your browser, this means that PHP has exhausted the maximum memory limit. This post will show 3 different ways on how you can increase the php memory limit and also explain when you should use them.

First, let’s see where is this limit coming from. Normally you will see from the error message what is the actual limit, as this will look like:
PHP Fatal error: Allowed memory size of X bytes exhausted (tried to allocate Y) in whatever.php
The default value might differ depending on what php version and linux distribution you are running, but normally this will be set to either 8M or 16M. For example on my debian etch, running on php 5.2 this is set by default at 16M.

In order to identify the current value on your system, look inside your php.ini and search for memory_limit:
memory_limit = 16M ; Maximum amount of memory a script may consume (16MB)

There are three ways to change this value, the obvious way - changing the global value from php.ini, but also an individual method to change it just for a script, or folder. Read the rest of this entry »