I use doctrine 2 PDO with mysql.
When stress testing the server, mysql reports a lot of aborted connections (up-to 20%).
I am trying to locate the issue.
I have found this tweak:
https://sroze.io/phpunit-mysql-too-many-connections-error-ab52cd5798c5
Setting processIsolation="true"
option in PhpUnit XML options file seems to do the trick.
From what I've observed, Doctrine uses persistent connections.
We've stumbled upon a problem, launching unit tests in symfony2, where the database was spammed with connections in "Sleep" status. The solution that worked for us:
$entityManager->getConnection()->close();
I have the same problem and
$entityManager->getConnection()->close();
seems to work, but works 'better' in some php versions if you add
gc_collect_cycles()
after closing connections. I'm still having that kind of issues in older php version, may be something related with the garbage collector I guess. Will keep you updated if I find a final solution for all php versions