Symfony2 / Doctrine2在运行查询时占用过多的内存

This is a separate issue that has developed from [this question thread][1]

while loading a simple page displaying a table of data (only 2 object entries) I'm getting a memory emergency error. Can anyone please tell me why?

here's the controller:

public function indexAction()
{

    $em = $this->getDoctrine()
        ->getManager();

    $titles = $em->getRepository('dvdLoggerdvdBundle:Titles')->getAllTitles();


    return $this->render('dvdLoggerdvdBundle:Page:index.html.twig', array(
        'titles' => $titles

    ));
}

then the getAllTitles from the repo

public function getAllTitles()
{
    // view all records in db
    $titles = $this->createQueryBuilder('t')
        ->select('t, u')
        ->leftJoin('t.addedBy', 'u')
        ->addOrderBy('t.title', 'DESC');

    return $titles->getQuery()->getResult();

}

the logfile is producing the following:

[2014-08-10 14:49:49] request.INFO: Matched route "dvdLoggerdvdBundle_homepage" (parameters: "_controller": "dvdLogger\dvdBundle\Controller\PageController::indexAction", "_route": "dvdLoggerdvdBundle_homepage") [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\DebugHandlersListener::configure". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ProfilerListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Bundle\FrameworkBundle\EventListener\SessionListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\FragmentListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\RouterListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\LocaleListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\Security\Http\Firewall::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Bundle\AsseticBundle\EventListener\RequestListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Symfony\Bundle\FrameworkBundle\DataCollector\RouterDataCollector::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Acme\DemoBundle\EventListener\ControllerListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Symfony\Component\HttpKernel\DataCollector\RequestDataCollector::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\ControllerListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\ParamConverterListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\HttpCacheListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\SecurityListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\TemplateListener::onKernelController". [] []
[2014-08-10 14:49:49] request.CRITICAL: Uncaught PHP Exception Doctrine\ORM\Query\QueryException: "[Semantical Error] line 0, col 10 near 'u FROM dvdLogger\dvdBundle\Entity\Titles': Error: 'u' is not defined." at C:\xampp\htdocs\dvdLogger\vendor\doctrine\orm\lib\Doctrine\ORM\Query\QueryException.php line 63 {"exception":"[object] (Doctrine\\ORM\\Query\\QueryException: [Semantical Error] line 0, col 10 near 'u FROM dvdLogger\\dvdBundle\\Entity\\Titles': Error: 'u' is not defined. at C:\\xampp\\htdocs\\dvdLogger\\vendor\\doctrine\\orm\\lib\\Doctrine\\ORM\\Query\\QueryException.php:63, Doctrine\\ORM\\Query\\QueryException: SELECT t, u FROM dvdLogger\\dvdBundle\\Entity\\Titles t ORDER BY t.title DESC at C:\\xampp\\htdocs\\dvdLogger\\vendor\\doctrine\\orm\\lib\\Doctrine\\ORM\\Query\\QueryException.php:41)"} []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\DebugHandlersListener::configure". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ProfilerListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Bundle\FrameworkBundle\EventListener\SessionListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\FragmentListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\RouterListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\LocaleListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\Security\Http\Firewall::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Bundle\AsseticBundle\EventListener\RequestListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Symfony\Bundle\FrameworkBundle\DataCollector\RouterDataCollector::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Acme\DemoBundle\EventListener\ControllerListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Symfony\Component\HttpKernel\DataCollector\RequestDataCollector::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\ControllerListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\ParamConverterListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\HttpCacheListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\SecurityListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\TemplateListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\HttpKernel\EventListener\ResponseListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\Security\Http\RememberMe\ResponseListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\HttpCacheListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\HttpKernel\EventListener\ProfilerListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Bundle\WebProfilerBundle\EventListener\WebDebugToolbarListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\HttpKernel\EventListener\StreamedResponseListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.finish_request" to listener "Symfony\Component\HttpKernel\EventListener\LocaleListener::onKernelFinishRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.finish_request" to listener "Symfony\Component\HttpKernel\EventListener\RouterListener::onKernelFinishRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.finish_request" to listener "Symfony\Component\Security\Http\Firewall::onKernelFinishRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.exception" to listener "Symfony\Component\HttpKernel\EventListener\ProfilerListener::onKernelException". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.exception" to listener "Symfony\Component\HttpKernel\EventListener\ExceptionListener::onKernelException". [] []
[2014-08-10 14:49:49] event.DEBUG: Listener "Symfony\Component\HttpKernel\EventListener\ExceptionListener::onKernelException" stopped propagation of the event "kernel.exception". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\HttpKernel\EventListener\ResponseListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\Security\Http\RememberMe\ResponseListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\HttpCacheListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\HttpKernel\EventListener\ProfilerListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Bundle\WebProfilerBundle\EventListener\WebDebugToolbarListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\HttpKernel\EventListener\StreamedResponseListener::onKernelResponse". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.finish_request" to listener "Symfony\Component\HttpKernel\EventListener\LocaleListener::onKernelFinishRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.finish_request" to listener "Symfony\Component\HttpKernel\EventListener\RouterListener::onKernelFinishRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.finish_request" to listener "Symfony\Component\Security\Http\Firewall::onKernelFinishRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.terminate" to listener "Symfony\Bundle\SwiftmailerBundle\EventListener\EmailSenderListener::onTerminate". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.terminate" to listener "Symfony\Component\HttpKernel\EventListener\ProfilerListener::onKernelTerminate". [] []
[2014-08-10 14:49:49] request.INFO: Matched route "_wdt" (parameters: "_controller": "web_profiler.controller.profiler:toolbarAction", "token": "b14d03", "_route": "_wdt") [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\DebugHandlersListener::configure". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ProfilerListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Bundle\FrameworkBundle\EventListener\SessionListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\FragmentListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\RouterListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\LocaleListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\Security\Http\Firewall::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Bundle\AsseticBundle\EventListener\RequestListener::onKernelRequest". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Symfony\Bundle\FrameworkBundle\DataCollector\RouterDataCollector::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Acme\DemoBundle\EventListener\ControllerListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Symfony\Component\HttpKernel\DataCollector\RequestDataCollector::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\ControllerListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\ParamConverterListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\HttpCacheListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\SecurityListener::onKernelController". [] []
[2014-08-10 14:49:49] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\TemplateListener::onKernelController". [] []
[2014-08-10 14:49:50] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\HttpKernel\EventListener\ResponseListener::onKernelResponse". [] []
[2014-08-10 14:49:50] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\Security\Http\RememberMe\ResponseListener::onKernelResponse". [] []
[2014-08-10 14:49:50] event.DEBUG: Notified event "kernel.response" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\HttpCacheListener::onKernelResponse". [] []
[2014-08-10 14:49:50] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\HttpKernel\EventListener\ProfilerListener::onKernelResponse". [] []
[2014-08-10 14:49:50] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Bundle\WebProfilerBundle\EventListener\WebDebugToolbarListener::onKernelResponse". [] []
[2014-08-10 14:49:50] event.DEBUG: Notified event "kernel.response" to listener "Symfony\Component\HttpKernel\EventListener\StreamedResponseListener::onKernelResponse". [] []
[2014-08-10 14:49:50] event.DEBUG: Notified event "kernel.finish_request" to listener "Symfony\Component\HttpKernel\EventListener\LocaleListener::onKernelFinishRequest". [] []
[2014-08-10 14:49:50] event.DEBUG: Notified event "kernel.finish_request" to listener "Symfony\Component\HttpKernel\EventListener\RouterListener::onKernelFinishRequest". [] []
[2014-08-10 14:49:50] event.DEBUG: Notified event "kernel.finish_request" to listener "Symfony\Component\Security\Http\Firewall::onKernelFinishRequest". [] []
[2014-08-10 14:49:50] event.DEBUG: Notified event "kernel.terminate" to listener "Symfony\Bundle\SwiftmailerBundle\EventListener\EmailSenderListener::onTerminate". [] []
[2014-08-10 14:49:50] event.DEBUG: Notified event "kernel.terminate" to listener "Symfony\Component\HttpKernel\EventListener\ProfilerListener::onKernelTerminate". [] []
[2014-08-10 14:49:59] request.INFO: Matched route "dvdLoggerdvdBundle_homepage" (parameters: "_controller": "dvdLogger\dvdBundle\Controller\PageController::indexAction", "_route": "dvdLoggerdvdBundle_homepage") [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener::injectLogger". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\DebugHandlersListener::configure". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ProfilerListener::onKernelRequest". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Bundle\FrameworkBundle\EventListener\SessionListener::onKernelRequest". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\FragmentListener::onKernelRequest". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\RouterListener::onKernelRequest". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\LocaleListener::onKernelRequest". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\Security\Http\Firewall::onKernelRequest". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.request" to listener "Symfony\Bundle\AsseticBundle\EventListener\RequestListener::onKernelRequest". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.controller" to listener "Symfony\Bundle\FrameworkBundle\DataCollector\RouterDataCollector::onKernelController". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.controller" to listener "Acme\DemoBundle\EventListener\ControllerListener::onKernelController". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.controller" to listener "Symfony\Component\HttpKernel\DataCollector\RequestDataCollector::onKernelController". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\ControllerListener::onKernelController". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\ParamConverterListener::onKernelController". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\HttpCacheListener::onKernelController". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\SecurityListener::onKernelController". [] []
[2014-08-10 14:49:59] event.DEBUG: Notified event "kernel.controller" to listener "Sensio\Bundle\FrameworkExtraBundle\EventListener\TemplateListener::onKernelController". [] []
[2014-08-10 14:49:59] doctrine.DEBUG: SELECT t0_.id AS id0, t0_.title AS title1, t0_.genre AS genre2, t0_.dateAdded AS dateAdded3, t0_.user_id AS user_id4 FROM titles t0_ ORDER BY t0_.title DESC [] []
[2014-08-10 14:50:10] emergency.EMERGENCY: Allowed memory size of 134217728 bytes exhausted (tried to allocate 123469824 bytes) {"type":1,"file":"C:\\xampp\\htdocs\\dvdLogger\\vendor\\twig\\twig\\lib\\Twig\\Extension\\Debug.php","line":66} []

If you want to show all the titles listed, you don't need a custom function, you can do something like this in you controller :

$titles = $em->getRepository('dvdLoggerdvdBundle:Titles')->findAll();

If you want to display all the titles the logged in user has added then do this:

$uid = $this->getUser()->getId();
$titles = $em->getRepository('dvdLoggerdvdBundle:Titles')->findBy(array('user_id'=>$uid));

I used the names you have shown here.

Alternative, suggestion, if you want to list sorted titles added by the logged in user, you can do this:

 public function getTitlesOfUser($userId) {
      return $this->createQueryBuilder('title')
                  ->where('title.user_id = :uid')
                  ->orderBy('title.title','DESC')
                  ->setParameter('uid', $userId)
                  ->getQuery()
                  ->getResult();
 }
 //or
 public function getTitlesOfUser($userObject) {
      return $this->createQueryBuilder('title')
                  ->where('title.addedBy = :user')
                  ->orderBy('title.title','DESC')
                  ->setParameter('user', $userObject)
                  ->getQuery()
                  ->getResult();
 }

ok the memory leak was being caused by a {{ dump(titles) }} in the template. I have no idea why it would do that as it was working before the join was added to pull the user.

Ive also managed to display the username using my first query above by accessing it with {{ title.addedBy.username }}

thanks for all the help, its been a steep learning curve!

I will though use the other query suggestion for loading titles from a specific user, so thank you for that.