I observed a strange behavior of my doctrine object. In my symfony project I'm using ORM with doctrine to save my data in a mysql database. This is working normal in the most situations. I'm also using gearman in my project, this is a framework that allows applications to complete tasks in parallel. I have a gearman job-server running on the same machine where also my apache is running and I have registered a gearman worker on the same machine in a seperate 'screen' session using the screen window manager. By this method, I have always access to the standard console out of the function registered for the gearman-worker.
In the gearman-worker function I'm invoking, I have access to the doctrine object by $doctrine = $this->getContainer()->get('doctrine') and it works almost normal. But when I have changed some data in my database, doctrine is using still the old data, which were stored before in the database. I'm totally confused, because I expected that by callling:
$repo = $doctrine->getRepository("PackageManagerBundle:myRepo");
$dbElement = $repo->findOneById($Id);
I'm always getting the current data entrys from my database. This is looking like a strange caching behavior, but I have no clue what I've made wrong.
I can solve this problem, by registering the gearman worker and function new:
$worker = new \GearmanWorker();
$worker->addServer();
$worker->addFunction
After that I've back the current state of my database, until I've changing something else. I'm oberserving this behavior only in my gearman worker function. In the rest of the application everthing is synchronized with my database and normal.
This is what I think may be happening. Could be wrong though.
A gearman worker is going to be a long-running process that picks up jobs to do. The first job it gets will then cause doctrine to load the entity into its object map from the database. But, for the second job the worker receives, doctrine will not perform a database lookup, it will instead check it's identity map and find it already has the object loaded and so will simply return the one from memory. If something else, external to the worker process, has altered the database record then you'll end up with an object that is out of date.
You can tell doctrine to drop objects from its identity map, then it will perform a database lookup. To enforce loading objects from the database again instead of serving them from the identity map, you should use EntityManager#clear().
More info here: https://www.doctrine-project.org/projects/doctrine-orm/en/2.6/reference/working-with-objects.html#entities-and-the-identity-map