title: Django - Loading Many-To-Many relationship admin page is so slow
body: <p>(Django 1.8) I have a table which has 4 many-to-many relationship to other tables.
  Two of these tables have so many entries and that is causing the admin page to load very slowly because it is trying to load all the entries in the lists.
  Is there a way to avoid the internal admin page query for loading all the entries of the big tables to speed up the admin page load?
  I think the best way is to only list the selected values but I'm not sure how.</p>
  
  <p>I'm not sure how to use <strong>limit_choices_to</strong> in here:</p>
  
  <pre><code>class Data(models.Model):
      pass # stuff here
  
  class Report(models.Model):
      data= models.ManyToManyField(Data)
  </code></pre>
  
  <p>I also tried adding this to my admin.py but it did not help at all. It's not limiting for some reason:</p>
  
  <pre><code>def queryset(self, request):
      qs = super(MyModelAdmin, self).queryset(request)
      if len(qs) &gt; 10:
          qs = qs[:10]
      return qs
  </code></pre>