Xtykutl

I'm using DRF. I found that receiving a POST with more than 1024 characters causes a ~1 second penalty, while anything less than that is effectively free. I've simplified this into this trivial example:

# views.py

import time

from rest_framework.decorators import api_view

from django.http import HttpResponse



@api_view(['POST'])

def test_endpoint(request):



    t = time.time()

    data = request.body

    total_time = time.time() - t



    print('got post data:', round(total_time, 3))

    return HttpResponse('body size:{} time:{}'.format(len(data), round(total_time, 3)))





# url.py

urlpatterns = [

    url(r'^test_endpoint', test_endpoint),

]

You can see that all I'm doing is reading the request.body and measuring the time it takes to do so. Then I respond with that time, and the len of the request.body (to prove I accessed it).

Then I execute these curls:

$ time curl -X POST http://127.0.0.1:8000/test_endpoint -d 0123456782345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567901234567890123456789012345678901234567

body size:1024 time:0.0

real    0m0.045s

user    0m0.006s

sys 0m0.009s

$ time curl -X POST http://127.0.0.1:8000/test_endpoint -d 01234567823456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345679012345678901234567890123456789012345678

body size:1025 time:0.999

real    0m1.020s

user    0m0.006s

sys 0m0.006s

You can see the second one has one extra character, and that causes a ~1 second penalty to ready request.body.

Why is that? How can I prevent this?

More Info

I made this as vanilla as I could. I created an new project with django-admin startproject helloworld_project .. I put the code above into it. And running it locally with python manage.py runserver. I don't have a webserver in front of it; I'm accessing it directly with my browser. That's all I'm doing.

Also, I'm doing this on Django==1.11. This problem seems to go away on Django==2.0. I cannot easily upgrade to 2.0. Is there a workaround for this issue on 1.11?