class Person(Base):
    __tablename__ = 'person'
    id = Column(Integer, primary_key=True)
    name = Column(String(100), nullable=False)
    type = Column(String(50))
    __mapper_args__ = {
        'polymorphic_identity': 'object',
        'polymorphic_on': type
        }

class Man(Person):
    __tablename__ = 'man'
    id = Column(Integer, ForeignKey('person.id'), primary_key=True)
    age = Column(String(100), nullable=False)
    __mapper_args__ = {'polymorphic_identity': 'man'}

class Config(Base):
    __tablename__ = "config"
    id = Column(Integer, primary_key=True)
    person = Column(Integer, ForeignKey('person.id'))
    address = Column(String)
    person_ref = relationship(Person)

man = session.query(Config).options(joinedload(Config.person_ref)).filter(Person.type == 'man').first()
print man.age

config = session.query(Config).options(FromCache("default")).first()
people = session.query(Person).options(FromCache("default")).with_polymorphic('*').get(config.person)