PDO::FETCH_INTO leaks memory; PHP 5.3.10, MySQL 5.0.77

gistfile1.aw

<?php

class A {
    public $m;
    public function __construct($pdo) {
        $sql = 'select 1 as m';
        $stmt = $pdo->prepare($sql);
        $stmt->setFetchMode(PDO::FETCH_INTO, $this);
        $stmt->execute();
    }
}

class B {
    public $m;
    public function __construct($pdo) {
        $sql = 'select 1 as m';
        $stmt = $pdo->prepare($sql);
        $stmt->execute();
        $res = $stmt->fetch(PDO::FETCH_ASSOC);
        foreach($res as $k => $v) $this->$k = $v;
    }
}

$pdo = new PDO('mysql:host=localhost;dbname=testdb', 'root', '');
echo "Start mem:".memory_get_peak_usage()."\n";

echo "-- fetch assoc --\n";
for($i=0; $i<100000; $i++) {
    $test = new B($pdo);
    unset($test);
    echo "mem: ".memory_get_peak_usage()."\r";
}
echo "\n";

echo "-- fetch into this --\n";
for($i=0; $i<100000; $i++) {
    $test = new A($pdo);
    unset($test);
    echo "mem: ".memory_get_peak_usage()."\r";
}
echo "\n";