Doctrine 2 query builder vs entity persist performance - doctrine-orm

Question

Summary: which is quicker: updating / flushing a list of entities, or running a query builder update on each?
We have the following situation in Doctrine ORM (version 2.3).
We have a table that looks like this
cow
wolf
elephant
koala
and we would like to use this table to sort a report of a fictional farm. The problem is that the user wishes to have a customer ordering of the animals (e.g. Koala, Elephant, Wolf, Cow). Now there exist possibilities using CONCAT, or CASE to add a weight to the DQL (example 0002wolf, 0001elephant). In my experience this is either tricky to build and when I got it working the result set was an array and not a collection.
So, to solve this we added a "weight" field to each record and, before running the select, we assign each one with a weight:
$animals = $em->getRepository('AcmeDemoBundle:Animal')->findAll();
foreach ($animals as $animal) {
if ($animal->getName() == 'koala') {
$animal->setWeight(1);
} else if ($animal->getName() == 'elephant') {
$animal->setWeight(2);
}
// etc
$em->persist($animal);
}
$em->flush();
$query = $em->createQuery(
'SELECT c FROM AcmeDemoBundle:Animal c ORDER BY c.weight'
);
This works perfectly. To avoid race conditions we added this inside a transaction block:
$em->getConnection()->beginTransaction();
// code from above
$em->getConnection()->rollback();
This is a lot more robust as it handles multiple users generating the same report. Alternatively the entities can be weighted like this:
$em->getConnection()->beginTransaction();
$qb = $em->createQueryBuilder();
$q = $qb->update('AcmeDemoBundle:Animal', 'c')
->set('c.weight', $qb->expr()->literal(1))
->where('c.name = ?1')
->setParameter(1, 'koala')
->getQuery();
$p = $q->execute();
$qb = $em->createQueryBuilder();
$q = $qb->update('AcmeDemoBundle:Animal', 'c')
->set('c.weight', $qb->expr()->literal(2))
->where('c.name = ?1')
->setParameter(1, 'elephant')
->getQuery();
$p = $q->execute();
// etc
$query = $em->createQuery(
'SELECT c FROM AcmeDemoBundle:Animal c ORDER BY c.weight'
);
$em->getConnection()->rollback();
Questions:
1) which of the two examples would have better performance?
2) Is there a third or better way to do this bearing in mind we need a collection as a result?
Please remember that this is just an example - sorting the result set in memory is not an option, it must be done on the database level - the real statement is a 10 table join with 5 orderbys.

Answer 1

Initially you could make use of a Doctrine implementation named Logging (\Doctrine\DBAL\LoggingProfiler). I know that it is not the better answer, but at least you can implement it in order to get best result for each example that you have.
namespace Doctrine\DBAL\Logging;
class Profiler implements SQLLogger
{
public $start = null;
public function __construct()
{
}
/**
* {#inheritdoc}
*/
public function startQuery($sql, array $params = null, array $types = null)
{
$this->start = microtime(true);
}
/**
* {#inheritdoc}
*/
public function stopQuery()
{
echo "execution time: " . microtime(true) - $this->start;
}
}
In you main Doctrine configuration you can enable as:
$logger = new \Doctrine\DBAL\Logging\Profiler;
$config->setSQLLogger($logger);