Knp Paginator with findAll() method

findAll() is compatible with Knp_paginator, you just have to give it to your paginator :

$query = $em->getRepository('Acme\FOOBundle\Entity\BAR')->findAll();
$paginator = $this->get('knp_paginator');
requests = $paginator->paginate(
    $query,
    $this->get('request')->query->get('page', 1), 
    5
);

KNP don't support sorting of array elements, as described here.

Better extract and sort data at database level. In your second example you fetch all data from table (and can be bigger), then you ask at the paginator to limit them. This don't perform well. So is better to do this work with a query and let do manage to the paginator element.

Currently KNP Paginator can paginate:

• array
• Doctrine\ORM\Query
• Doctrine\ORM\QueryBuilder
• Doctrine\ODM\MongoDB\Query\Query
• Doctrine\ODM\MongoDB\Query\Builder
• Doctrine\Common\Collection\ArrayCollection - any doctrine relation collection including ModelCriteria - Propel ORM query
• array with Solarium_Client and Solarium_Query_Select as elements

See the doc fererence for detail

my two cents

FindAll returns an array. The knp paginator requires a doctrine query object.