Base Command object for saving huge amout of entities to prevent memory leaks.

PersistLotEntitiesCommand.php

<?php

namespace Acme\DemoBundle\Command;

use Doctrine\ORM\EntityManager;
use Symfony\Bundle\FrameworkBundle\Command\ContainerAwareCommand;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;

abstract class PersistLotEntitiesCommand extends ContainerAwareCommand
{

    /** @var EntityManager */
    private $entityManager;

    /** @var int */
    private $persistedEntities = 0;

    /**
     * @param InputInterface  $input
     * @param OutputInterface $output
     */
    protected function initialize(InputInterface $input, OutputInterface $output)
    {
        parent::initialize($input, $output);

        $this->entityManager = $this->getContainer()->get('doctrine.orm.entity_manager');
        $this->entityManager->getConnection()->getConfiguration()->setSQLLogger(null); // Save memory

        gc_enable(); // Save memory
    }

    /**
     * @param $entity
     */
    protected function persistEntity($entity)
    {
        $this->entityManager->persist($entity);

        if ($this->persistedEntities > $this->getPersistThreshold()) {
            $this->flush();
        }

        ++$this->persistedEntities;
    }

    /**
     * Entity manager flush and clear unused objects.
     */
    private function flush()
    {
        $this->entityManager->flush();
        $this->entityManager->clear();
        gc_collect_cycles(); // Save memory
        $this->persistedEntities = 0;
    }

    /**
     * How many entities should be persisted before flushing.
     * 
     * @return int
     */
    public function getPersistThreshold()
    {
        return 99;
    }

    /**
     * @param InputInterface $input
     * @param OutputInterface $output
     * @return int
     * @throws \Exception
     */
    public function run(InputInterface $input, OutputInterface $output)
    {
        $statusCode = parent::run($input, $output);

        $this->flush();

        return $statusCode;
    }
}