Out Of Memory Exception Xampp - php

Question

I have this function :
public function RemplirTab($nomCol)
{
$username = $this->getDb()->getUsername();
$sql = "SELECT DISTINCT $nomCol
FROM nautilus_users_page, nautilus_users_acces, nautilus_users_droit, nautilus_users_privilege, nautilus_users_menu
WHERE nautilus_users_page.id_page = nautilus_users_acces.id_page
AND nautilus_users_acces.id_droit = nautilus_users_droit.id_droit
AND nautilus_users_droit.id_droit = nautilus_users_privilege.id_droit
AND nautilus_users_page.id_menu = nautilus_users_menu.id_menu
AND login='$username'";
$row = $this->getDb()->fetchAssoc($sql, array($nomCol, $username));
$i = -1;
$Tab = array();
while($result = $row)
{
$i = $i+1;
$Tab[$i] = $result[$nomCol];
}
return $Tab;
}
Which shows me an error:
I use Silex with Doctrine DBAL.
This function was mysqli with this form:
function RemplirTab($nomCol, $login)
{
$sql = "SELECT DISTINCT $nomCol
FROM nautilus_users_page, nautilus_users_acces, nautilus_users_droit, nautilus_users_privilege, nautilus_users_menu
WHERE nautilus_users_page.id_page = nautilus_users_acces.id_page
AND nautilus_users_acces.id_droit = nautilus_users_droit.id_droit
AND nautilus_users_droit.id_droit = nautilus_users_privilege.id_droit
AND nautilus_users_page.id_menu = nautilus_users_menu.id_menu
AND login='$login'";
$link = connectdb('nautilus_users');
$req = execquery($link, utf8_decode($sql));
$i = -1;
while($row = $req->fetch_assoc())
{
$i = $i+1;
$Tab[$i] = $row[$nomCol];
}
return $Tab;
}