Doctrine2 $em->persist($entity) on foreach loop

From the Doctrine documentation, it says that inserts are best performed with batch. And its a development of @AlterPHP 's answer.

You could use :

$batchSize = 20;

for ($i = 1; $i <= 10000; ++$i) {

    $car = new Car();
    // ... set number of wheels, but should always be to 4 right ?

    $em->persist($car);

    if (($i % $batchSize) === 0) {
        $em->flush();
        $em->clear(Car::class); // Detaches all Car objects from Doctrine!
    }
}

$em->flush(); // Persist objects that did not make up an entire batch
$em->clear(Car::class);

PS: i just read that from Doctrine 13.1. Bulk Inserts section. Now all you'll need is a bigger parking !

As suggested by greg0ire, this link describes how Doctrine optimizes INSERT statements : https://www.slideshare.net/jwage/doctrine-2-not-the-same-old-php-orm/47-sflive2010_Insert_Performance_Inserting_20 (have a look from slide #47). It uses transactions but doesn't group INSERT of same objects in a unique statement.

If you really need to divide the amount of data you pass to your DB server at once, I suggest you process EntityManager::flush() every x statement.

Change this code:

foreach ($dataset as $data) {
    $entity = new Entity();
    // ---- Some setting operations on the entity
    $em->persist($entity);
}

to:

foreach ($dataset as $data) {
    $entity = new Entity();
    // ---- Some setting operations on the entity
    $em->persist($entity);
    $em->flush();
    $em->clear();
}