Django rest 框架需要很长时间才能返回嵌套的序列化数据

Question

We are having four models which are related, While returning queryset serializing the data is too slow(serializer.data). Below are our models and serializer.

Why django nested serializer is taking too long to return rendered response. What are we doing wrong here?

Note:Our DB lies in AWS when connected from EC2 instance it is ok but when tried from my localhost it is insanely slow. And the size of json it returns is 700KB.

models.py

class ServiceType(models.Model):
    service_name = models.CharField(max_length = 100)
    description = models.TextField()
    is_active = models.BooleanField(default = 1)

class Service(models.Model):
    service_name = models.CharField(max_length = 100)
    service_type = models.ForeignKey(ServiceType, related_name = "type_of_service")
    min_duration = models.IntegerField() ##duration in mins

class StudioProfile(models.Model):

   studio_group = models.ForeignKey(StudioGroup, related_name = "studio_of_group")
   name = models.CharField(max_length = 120)

class StudioServices(models.Model):
   studio_profile = models.ForeignKey(StudioProfile, related_name = "studio_detail_for_activity")
   service = models.ForeignKey(Service, related_name = "service_in_studio")

class StudioPicture(models.Model):
   studio_profile  = models.ForeignKey(StudioProfile, related_name = "pic_of_studio")
   picture = models.ImageField(upload_to = 'img_gallery', null = True, blank = True)

serializers.py

class ServiceTypeSerializer(serializers.ModelSerializer):

    class Meta:
       model = ServiceType
       fields = ('id', 'service_name')

class ServiceSerializer(serializers.ModelSerializer):

    service_type = ServiceTypeSerializer()
    class Meta:
        model = Service
        fields = ('id', 'service_type', 'service_name')

class StudioServicesSerializer(serializers.ModelSerializer):
    service = ServiceSerializer()
    class Meta:
        model = StudioServices
        fields = ('service','price','is_active','mins_takes')

class StudioPictureSerializer(serializers.ModelSerializer):
    class Meta:
        model = StudioPicture
        fields = ('picture',)

class StudioProfileSerializer(serializers.ModelSerializer):
    studio_detail_for_activity = StudioServicesSerializer(many = True)
    pic_of_studio = StudioPictureSerializer(many = True)
    class Meta:
       model = StudioProfile
       fields = ('id', 'name','studio_detail_for_activity','pic_of_studio')

views.py

class StudioProfileView(ListAPIView):
    serializer_class = StudioProfileSerializer
    model = StudioProfile
    def get_queryset(self):
        try:
           queryset = self.model.objects.all()
        except Exception ,e:
           logger_error.error(traceback.format_exc())
           return None
        else:
           return queryset

Answer 1

Did you checked which part is the slow one? like, How many records do you have in that db? and I would try to run the query and check if the query is slow, then I'd check the serializers with less than 100 registers and so on.

I'd recommend you to read this article http://www.dabapps.com/blog/api-performance-profiling-django-rest-framework/ in order to evaluate how to profile your API

Regards