Verify address book contacts iOS from PHP server -

i need check of addressbook users using ios app (using emails). this, send contacts list php server , check emails, registered. then, return array of users , show them in ios tableview. problem when have 100-200 contacts, retrieval lightening fast, when have 1000-1500 contacts takes @ least 3-4 minutes. how can improve it?

php code:     $handle = fopen('php://input','r');     $jsoninput = fgets($handle);     // decoding json array     $array = json_decode($jsoninput,true);      if (empty($array)) {         echo '<h1>array empty!!!<h1>';         return;     }      require('dbconnection.php');      $dbconnection = new dbconnection;      $link = $dbconnection->connecttodatabase();       if ($link)      {         $dbconnection->selectdatabase();          foreach($array $subarray)         {             foreach($subarray['email'] $email)             {                  $query="select email,picture user email='$email'";                  $result=  mysql_query($query);                   $row = mysql_fetch_assoc($result);                   if(mysql_num_rows($result) > 0)//if finds row                  {                      $contact = array(                         "fullname" => $subarray['fullname'],                          "email"   => $email,                         "picture" => "http://www.mysite.co/project/users/images/".$email."."."jpg"."?".time()                          );                          $returningarray[] =  $contact;                  }             }         }          echo json_encode($returningarray);     } 

if think of performance first thing need check how many db calls there because slow. need in case perform single mysql request emails got ios call:

select email, picture user email in ('email1', 'email2', ...) 

then need iterate through results of sql call, know of passed emails exist in database.

and should consider switching pdo sure.