Define doctrine sql query logger

defaultController.php

<?php 

class myController extends Controller
{
    public function indexAction()
    {   
        // Start setup logger
        $doctrine = $this->getDoctrine();
        $doctrineConnection = $doctrine->getConnection();
        $stack = new \Doctrine\DBAL\Logging\DebugStack();
        $doctrineConnection->getConfiguration()->setSQLLogger($stack);
        $em = $doctrine->getManager();
        // End setup logger

        /**
         * Execute here all your queries
         *  $em->getRepository(...)->find(...)
         */
         
        return $this->render('somebundle:myBundle:index.html.twig',array(
            'stack' => $stack
        ));
    }
}