Getting odd behavior from $query->setMaxResults() - doctrine-orm

Question

When I call setMaxResults on a query, it seems to want to treat the max number as "2", no matter what it's actual value is.
function findMostRecentByOwnerUser(\Entities\User $user, $limit)
{
echo "2: $limit<br>";
$query = $this->getEntityManager()->createQuery('
SELECT t
FROM Entities\Thread t
JOIN t.messages m
JOIN t.group g
WHERE
g.ownerUser = :owner_user
ORDER BY m.timestamp DESC
');
$query->setParameter("owner_user", $user);
$query->setMaxResults(4);
echo $query->getSQL()."<br>";
$results = $query->getResult();
echo "3: ".count($results);
return $results;
}
When I comment out the setMaxResults line, I get 6 results. When I leave it in, I get the 2 most recent results. When I run the generated SQL code in phpMyAdmin, I get the 4 most recent results. The generated SQL, for reference, is:
SELECT <lots of columns, all from t0_>
FROM Thread t0_
INNER JOIN Message m1_ ON t0_.id = m1_.thread_id
INNER JOIN Groups g2_ ON t0_.group_id = g2_.id
WHERE g2_.ownerUser_id = ?
ORDER BY m1_.timestamp DESC
LIMIT 4
Edit:
While reading the DQL "Limit" documentation, I came across the following:
If your query contains a fetch-joined collection specifying the result limit methods are not working as you would expect. Set Max Results restricts the number of database result rows, however in the case of fetch-joined collections one root entity might appear in many rows, effectively hydrating less than the specified number of results.
I'm pretty sure that I'm not doing a fetch-joined collection. I'm under the impression that a fetch-joined collection is where I do something like SELECT t, m FROM Threads JOIN t.messages. Am I incorrect in my understanding of this?

Answer 1

An update : With Doctrine 2.2+ you can use the Paginator http://docs.doctrine-project.org/en/latest/tutorials/pagination.html

Answer 2

Using ->groupBy('your_entity.id') seem to solve the issue!

Answer 3

I solved the same issue by only fetching contents of the master table and having all joined tables fetched as fetch="EAGER" which is defined in the Entity (described here http://www.doctrine-project.org/docs/orm/2.1/en/reference/annotations-reference.html?highlight=eager#manytoone).
class VehicleRepository extends EntityRepository
{
/**
* #var integer
*/
protected $pageSize = 10;
public function page($number = 1)
{
return $this->_em->createQuery('SELECT v FROM Entities\VehicleManagement\Vehicles v')
->setMaxResults(100)
->setFirstResult($number - 1)
->getResult();
}
}
In my example repo you can see I only fetched the vehicle table to get the correct result amount. But all properties (like make, model, category) are fetched immediately.
(I also iterated over the Entity-contents because I needed the Entity represented as an array, but that shouldn't matter afaik.)
Here's an excerpt from my entity:
class Vehicles
{
...
/**
* #ManyToOne(targetEntity="Makes", fetch="EAGER")
* #var Makes
*/
public $make;
...
}
Its important that you map every Entity correctly otherwise it won't work.