In response to my emails to the Zend Framework I18N list and my previous post, Thomas, the author of the Zend_Translate framework items mailed back to the list here:

> 2) gettext is a more expensive version of using the arrays backend.

No… it’s a less expensive version. What takes time is reading the original
source. Your processor is always faster than your harddrive.
It is better to do some computations than reading a bigger file. And mo
files are much smaller than the same sized array files.

This still seems wrong to me, so I’ve done a bit more analysis. I have now got XDebug up and running in my portable environment, so I can really see the details of the costs. Now, to caveat all this, I’m running all this from a USB key on a laptop that’s doing a number of other background tasks, so, the performance is not isolated. Due to this I’ll be looking at percentages of time in Wincachegrind, not actual execution times.

Now, to test this I have generated two files. One of which is a .po containing 1000 phrases which I have compiled to a .mo file. The other is a PHP array in a PHP file containing the same 1000 translations. I generated this with a script, the translations are a bit simple:

From the .po file:

msgid “String 0″
msgstr “String Translated 0″

From the .php file:

‘String 0′=> ‘String Translated 0′,

I have then written a simple PHP file which translates 50 of these items. A reasonable enough test I think. Firstly, to test the translation using the fast Zend_Translate gettext options:

require_once 'Zend/Translate.php';
i = new Zend_Translate('gettext', '/development/language/test.en.mo', 'en');
 
function _($s)
{
    global $i;
    $s = $i->_($s);
    echo($s."<br/>\n");
}
 
_('String 1');
_('String 2');
...

I then ran this file and loaded the cachegrind output into WinCacheGrind. 87.88% of the execution time was spent in Zend_Translate_Adapter_Gettext->_loadTranslationData. Performing translations took 1.99% of the time.

Next I used my PHP array and the Zend_Translate array backend:

require_once 'Zend/Translate.php';
require_once '/development/language/test.en.php';
$i = new Zend_Translate('array', $LANGUAGE, en);

(The rest of the file remains the same). I then ran this and checked the output. loadTranslationData took 78.36% of the time. Performing translations took 2.86% of the time.

My third test was just to use the test.en.php file and a simple translation function:

require_once '/development/language/test.en.php';
function _($s) {
  global $LANGUAGE;
   $s = (array_key_exists($s, $LANGUAGE)) ? $LANGUAGE[$s] : $s;
  return $s;
}

The first thing to note was that the Zend_Translate items took over 20ms each. This one not using Zend at all took 2.8ms. The require_once statement took 1.83% of that time. Then it was just repetition of an un-recordably-fast translation 50 times.

So what do I draw from this? I draw from this that for simple translations, you can’t beat a very, very simple system with just an array of translations. I haven’t looked in any depth at the other services offered by Zend_Translate, but it does allow you to add multiple translations and translate in multiple languages. But, do you have a use-case for that?

If your UI needs to display in a single language, but translate that language, take the simple approach. It needs a little extension to support modular languages, but look at the PHPBB3 implementation and you can’t go far wrong. That loads modular translation files (just to keep that trivial require_once cost down) each of which array_merge’s back into a single translation array which is key’d by constants.

Fast.

My cachegrind files for your reading pleasure:
Zend_Translate - Array
Zend_Translate - Gettext
Non-Zend_Translate

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