When a 'backend' parameter is passed to the PostgresConnection __init__, it is ignored.
from postgres/pgconnection.py :
This first line in __init__,
backends = kw.pop('backend', None) or 'psycopg'
should be like:
backends = backend or 'psycopg'
or just:
backends = backend
since the backend param has a default value of 'psycopg'.
You are right.
backends = backend
is enough. Fixed in the revision 4062, will be in the next round of releases. Thank you!