Undefined index error upon $em->clear() in Symfony2

Question

I have written a Symfony command to import some data from an API. It works but the problem is my PHP memory usage increases when I insert a big JSON in my database. And my unitO

Answer 1

Try to reset the entity manager with:

$this->getContainer()->get('doctrine')->resetEntityManager();

and then:

$em = $this->getContainer()->get('doctrine')->getEntityManager();

Answer 2

Symfony logs all SQL queries in dev environment, so first you need to disable it

// disable logger
$em->getConnection()->getConfiguration()->setSQLLogger(null);

You may use event listeners on entities, it may also increase memory usage. You can disable them like so

// remove all listeners
foreach ($em->getEventManager()->getListeners() as $event => $listeners) {
    foreach ($listeners as $listener) {
        $em->getEventManager()->removeEventListener($event, $listener);
    }
}

Remove unset from your code, there is no need for them, as you clear entity manager every step of your loop.

// save and clear
$em->flush();
$em->getUnitOfWork()->clear();

Remember that doctrine can optimize your queries, and improve perfomance if you group queries into one flush. So the best practice would be to execute flush once over some parts of your data. For example:

// collect 100 entities and then save them
if (($i % 100) == 0) {
    $em->flush();
    $em->getUnitOfWork()->clear();
}