Question

This is my code:

    $size_all_colonies = sizeof($all_colonies) ;
    $size_all_coods = sizeof($all_cood) ;
    for ( $i = 0 ; $i < $size_all_colonies  ; $i++ )
    {
        $id = $all_colonies[$i]['id'] ;
        $colony_name = $all_colonies[$i]['colony_name'] ;
        $colony_node = $dom->createElement('colony');
        $response->appendChild($colony_node);
        $colony_text_node = $dom->createTextNode($colony_name) ;
        $colony_node->appendChild($colony_text_node) ;

        $id_node = $dom->createElement('id_node') ;
        $colony_node->appendChild($id_node) ;
        $id_node->appendChild($dom->createTextNode($id)) ;

        $coods = "" ;
        for ( $j = 0 ; $j < $size_all_coods ; $j++ )
        {
            if ( $id == $all_cood[$j]['colony_id'] )
            {

                $coods .= $all_cood[$j]['latitude'].",".$all_cood[$j]['longitude'].";" ;
               // break ; 
            }
        }
        $coods =substr($coods,0,-1);
        $cood_node = $dom->createElement('cood_node') ;
        $colony_node->appendChild($cood_node) ;
        $cood_node->appendChild($dom->createTextNode($coods)) ;
        echo $id . '   ' ;
    }

Explanation:

all_colonies = is a multi-dimensional array – size- 7000

all_coods – another multi array – size 70000

all_cood[$j][‘colony_id’] is foreign key and corresponds to all_colonies[$i][‘id’].

This is constructing a response for an ajax request, which ideally should take a few minutes, but is taking a few hours 🙁 . And it slows down gradually, like the first 1000 loops/iterations (outer for) happen in under 30 seconds, but the next thousand takes minutes, and the next thousand forever.

Please help!

Thanks

edit: the break statement was not required! I added when I was desperate to improve the performance, but it should not be there..

Answer 1

Something you could try is setting up the all_coods variable to be indexed by the id, rather than just being an array. This way you will save time with the inner loop.

For example:

$list = tons of stuff

//now, loop through the stuff once to generate 
//the assoc array that's indexed by IDs
$listMap = array();
foreach($list as $item) {
    $listMap[$item['id']] = $item;
}

//the main looping
foreach(loop an array) {
    if(isset($listMap[$id])) {
        //you just saved looping through the other array.
    }
}