DRF does not release memory after large JSON/XML request data is read or send through response

[Dhananjay1992]

##Framework version details
Django==3.1.4
djangorestframework==3.12.2
python 3.8.10
gunicorn==20.0.4

I have observed that when some data in the form of JSON or XML is read through request or serializers the memory is never released.

I have one very basic API with APIView which has kind of below code.

`

class SomeClass(APIView):

serializer_class = JsonObjectSerializer
def post(self, request):
    serializer_object = JsonObjectSerializer(data=self.request.data)
    assert serializer_object.is_valid(), "Some error"
    obj1 = serializer_object.validated_data.get('obj1')
    obj2 = serializer_object.validated_data.get('obj2')
    result = perform_some_operation(obj1, obj2, serializer_object)
    response = construct_fe_response(result)
    return Response(status=status.HTTP_200_OK, data=response)

`
This does some JSON object reading through serializer and it process it and then send processed result as response. In this operation I see every time when JSON object comes this operation increases memory lets say by ~20MB (for large/medium sized JSON data) and if I have 100 calls for this API it goes around ~2GB of my RAM. even after few days the memory is never released.

I have used memory_profile on my processing and post method of above code and result is that when serializer_object = JsonObjectSerializer(data=self.request.data) this line is called memory increased to ~15 MB and then it never releases it.
It might be duplicate of memory issues in DRF but this still happens and needs attention.

I am using gunicorn with wsgi

[akx]

JsonObjectSerializer doesn't seem to be a DRF class, so you would probably need to post the code for it so we can investigate if it's leaking.

[Dhananjay1992]

@akx JsonObjectSerializer is super simple serialiser

`class M(models.Model):
obj1 = models.TextField()
obj2 = models.TextField()

class JsonObjectSerializer(serializers.ModelSerializer):
class Meta:
fields = 'all'
model = M
`

[lovelydinosaur]

Seems like a duplicate of #5146 which has this resolution... #5146 (comment)