Question

Can I release the memory generated from the included file, here are my codes

a.php

<?
echo memory_get_usage();
include_once "b.php";
echo memory_get_usage();
$n = new obj();
echo memory_get_usage();
?>

b.php

<?
class obj {
protected $_obj = array{
....
}

function ....

}

?>

I checked that, after I include the b.php, the memory use will increase, which is more higher than create a new object. The result is as below

348832
496824
497072

So, how can I release the included file’s memory?

Answer 1

I think PHP cannot de-include (I mean, free the memory space hold by included file) since the contents of the file may be used later. This is a design choice of PHP creators.

After your PHP script finishes, it will free consumed memory, do not worry about it too much unless it really makes too overhead and you have a high volume traffic load.

If there is (let’s say a huge) object coming from included file you want to deallocate right now, use unset($obj). It will help some. You should read more about PHP Garbage Collection policy to have a fine tuning.