OutOfMemoryException in PDOConnection using Doctrine iterate result

query.php

<?php
// 7041 rows with content being BLOB content - total table size ~ 2.4 GB
$instructionRepository = $this->getDoctrine()->getRepository('PlusquamContractBundle:Instruction');
$instructionQueryBuilder = $instructionRepository->createQueryBuilder('i')
    ->where('i.content IS NOT NULL')
    ->orderBy('i.id', 'desc');

$instructions = $instructionQueryBuilder->getQuery()->iterate();
?>

Nice!