psycopg2cffi == bad idea
https://liangnuren.wordpress.com/2013/10/22/python-and-pypy-pyscopg2-vs-psycopg2cffi/
https://stackoverflow.com/questions/25090573/django-memory-leak-possible-causes
http://blog.gingerlime.com/2011/django-memory-leaks-part-i/
https://docs.djangoproject.com/en/1.11/topics/db/optimization/
Evaluation
https://docs.djangoproject.com/en/1.11/ref/models/querysets/#when-querysets-are-evaluated
https://docs.djangoproject.com/en/1.11/topics/db/queries/#caching-and-querysets
http://www.binarytides.com/linux-command-check-memory-usage/
http://smira.ru/wp-content/uploads/2011/08/heapy.html
http://klauslaube.com.br/2012/11/02/entendendo-o-cgi-fastcgi-e-wsgi.html