Fixing max_user_connections in PHP class using PDO - php

Question

I have been adapting an older abstraction layer to use PDO but I am running into user x has more than 'max_user_connections' active connections SQLSTATE[HY000] [1203] errors when looping through large sets. I have been reading on http://php.net/manual/en/pdo.connections.php but all of my attempts to unset the $dbh from within the loops result in errors from having ended the connection.
Base class looks like
class DB {
public $pdo;
private $host = DB_HOST;
private $user = DB_USER;
private $pass = DB_PASS;
private $dbname = DB_NAME;
public function __construct()
{
$this->connect();
}
private function connect()
{
$options = array(
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
);
try {
$this->pdo = new PDO("mysql:host=$this->host;dbname=$this->dbname;charset=utf8;", $this->user, $this->pass, $options);
} catch(PDOException $e) {
echo $e->getMessage();
}
}
public function __sleep()
{
return array('dsn', 'username', 'password');
}
public function __wakeup()
{
$this->connect();
}
public function __destruct()
{
$this->connection = null;
$this->pdo = null;
unset($this->pdo);
}
// CRUD methods follow including
function retrieve($where, $groupBy='', $order_by='') {
$query = "SELECT * FROM `$this->table` $where $groupBy $order_by";
$q = $this->pdo->prepare($query);
$q->execute();
$result = $q->fetchAll(PDO::FETCH_CLASS | PDO::FETCH_PROPS_LATE,get_class($this));
// was $result = $q->fetchAll(PDO::FETCH_CLASS,get_class($this));
$this->query_log($query);
$q = null;
if ($result == 'NULL') {
return false;
} else {
return $result;
}
} // retrieve()
And an example that has the errors would be
if (in_array($_GET['type'], $types)) {
$type = $_GET['type'];
$rsObj = new ReservedSlug;
if ($type == 'artist') {
$obj = new CalendarArtist;
$slugfield = 'urlSlug';
$namefield = 'name';
} else if ($type == 'event') {
$obj = new CalendarEvent;
$slugfield = 'urlSlug';
$namefield = 'name';
} else if ($type == 'location') {
$obj = new Location;
$slugfield = 'UrlSlug';
$namefield = 'LocationName1';
}
$needslug = $obj->retrieve("TRIM(`$namefield`) != '' AND (`$slugfield` = '' OR `$slugfield` IS NULL) LIMIT 0,400");
if ($needslug) {
foreach ($needslug as $ns) {
$testslug = slugify($ns->$namefield);
list($reserved) = $rsObj->retrieve("`slug` = '$testslug' AND `type` = '$type'");
if (!$reserved) {
list($test) = $obj->retrieve("`$slugfield` = '$testslug'");
if ($test) {
for ($i = 2; $i < 26; $i++) {
list($test) = $obj->retrieve("`$slugfield` = '$testslug-$i'");
if (!$test) {
$slug = $testslug . '-' . $i;
}
}
} else { // not found in table
$slug = $testslug;
}
} else { // was reserved
$slug = false;
}
echo $ns->$namefield . " gets $slug<p>";
} // foreach needslug
} // if needslug
} // type found in array
So I need to understand how to not create new connections when an active connection is available and how to properly __destruct() these child objects. Where am I going wrong?