what happen with my memcache (and php), please help

[son at raider.co.nz]

Hello all

I have a php page that call function bellow:

----------------------

function redirect_process($key) {
    ....
	$value = $memcache->get($key); //get value from memcache
	if (!$value) {
			if (!$memcache->get('temp:'.$key)) {
	    		$memcache->set('temp:'.$key, 1); //set 1
                echo 'This key is NOT set';
				usleep(50000000); //sleep for 50 seconds
				$memcache->delete('temp:'.$key); //delete this key
    	    }
			else if	($memcache->get('temp:'.$key))  {
				echo 'this key AREADY set';
         }
    }
}

-------------------------------------

Then I hit the page with a key that is not in memcache yet sing browsers 
(firefox) in my computer. The second is after the first.

However, I never get the message "this key AREADY set".

In both cases, I only get 'This key is NOT set'.

I donot know why. I think that my code is very clear.

Note: I ONLY "get this key AREADY set" message when I remove the code:

usleep(50000000);
$memcache->delete('temp:'.$key);


Could you please help
regards
shoa