Model representation with FK, exceeding queries

[Cleiton Lima]

I do not know if it is a bug or has already been commented

# models.py

class State(models.Model):
    name = models.CharField(_('name'), max_length=60)


    class Meta:
        verbose_name = _('state')
        verbose_name_plural = _('states')


    def __str__(self):
        return self.name

class City(models.Model):
    name = models.CharField(_('name'), max_length=60)
    state = models.ForeignKey('State', verbose_name=_('state'), related_name='cities')


    class Meta:
        verbose_name = _('city')
        verbose_name_plural = _('cities')


    def __str__(self):
        return '{} - {}'.format(self.name, self.state.name)

# forms.py

class AnythingForm(forms.ModelForm):
    class Meta:
        model = Anything
        fields = ['city']

# template.html

{{form.city}}

I have 5565 records in model City.

Django==1.11.1 execute 5565 queries to render select

Django==1.10.7 only 2

If replace return '{} - {}'.format(self.name, self.state.name) to self.name in __str__ of city model, it works. 

Is this really a problem or my mistake?

[Simon Charette]

Hello Cleiton,

I'm a bit surprised only two queries were executed on 1.10 as each

time a city string representation is created the associated state

will need to be fetched as well.

Were you using any form of select_related()/prefetch_related() to make

sure this wasn't an issue? It's possible that the template based widget

rendering introduced in 1.11 broke your optimization somehow that would

be an actual bug.

Simon

[Cleiton Lima]

I just found the problem. The plugin I use to render this select is breaking in django 1.11.
I really did not see this problem.