python - How to optimize number of queries in the Django view? -

i show comments in topic detail view. 2 queries happens in view: 1 topic , 1 comments list. understand select_related technique can't used here since there 2 different querysets created in view. there way decrease number of queries one?

application code follows below.

app/models.py

class topic(models.model):      headline = models.charfield(max_length=400)     description = models.textfield()     created = models.datetimefield(auto_now_add=true)     modified = models.datetimefield(auto_now=true)     author = models.foreignkey(user, related_name='topics')  class comment(models.model):      headline = models.charfield(blank=true, max_length=400)     description = models.textfield()     created = models.datetimefield(auto_now_add=true)     modified = models.datetimefield(auto_now=true)     author = models.foreignkey(user, related_name='comments')     topic = models.foreignkey(topic, related_name='comments') 

app/views.py

class topicdetail(detailview):      queryset = topic.objects.select_related('author').all()     context_object_name = 'topic'      def get_context_data(self, **kwargs):          context = super().get_context_data(**kwargs)         topic = self.object         context['comments'] = topic.comments.select_related('author').all()         return context 

app/templates/app/topic_detail.html

{{ topic.headline }} {{ topic.description }} {{ topic.created }} {{ topic.modified }} {{ topic.author }} {% comment in comments %}     {{ comment.headline }}     {{ comment.description }}     {{ comment.author }} {% endfor %} 

even in pure sql such "single" query hard.

basically need repeat topic data in each comment! in pseudo code:

select comment.*, topic.* comments right join topic 

that massive data processing/transfer overhead. whole operation should take more time, resources separate queries.

if need it, write custom function in comment topic model, pure sql.