I’ve always heard the include_once() and require_once() functions were computationally expensive in PHP, but I never knew how much. I tested the following out on my i7 2010 MacBook Pro using PHP 5.3.4 as shipped by Apple.
This first test uses include_once() to keep track of how often a file is included:
$includes = Array();
$file = ‘benchmarkinclude’;
for($i=0; $i < 1000000; $i++){
include_once($file.‘.php’);
}
Took: 10.020140171051 sec
This second example uses include() and uses in_array() to keep track of if I loaded the include:
$includes = Array();
$file = ‘benchmarkinclude’;
for($i=0; $i < 1000000; $i++){
if(!in_array($file, $includes)){
include($file . ‘.php’);
$includes[] = $file;
}
}
Took: 0.27652382850647 sec
For both, the include had the following computation:
$x = 1 + 1;
Lesson learned: Avoid using _once if you can avoid it.
Update: That means something like this will theoretically be faster:
$rja_includes = Array();
function rja_include_once($file){
global $rja_includes;
if(!in_array($file, $rja_includes)){
include($file);
$rja_includes[] = $file;
}
}