Symfony 2 : Avoid doctrine’s memory leaks with commands

While running some specific long-time import processes through Doctrine by running a Symfony 2 command, I noticed some memory leaks.

I’m using MongoDB on top of doctrine.

For example:
First import : 22 MB used
Last import (100k+): 500+ MB used

Couple of tips:

1. Call $dm->clear() regularly to clean up doctrine cache. But, do not forget that all objects in cache will be swept
2. This is the REAL tip: add –no-debug to your command line

php app/console --no-debug my:bundle:command

The 1st tip helps a little bit, the 2nd one is very efficient. And it has another impact: it speeds up the execution.