Thanks for your answer. So the slow performance issue occurs whether the
request is performed using JSON or from the browseable API.
>>> import requests
>>> PARAMS = {'latitude': 38.2, 'longitude': -122.1}
>>> requests.get(url=URL, auth=AUTH, params=dict(PARAMS, limit=1000))
# 1 loop, best of 3: 4.21 s per loop - using %timeit
We do have django-filters with cripy-forms in installed apps, and it is
listed as the default backend in the viewset:
filter_backends = (filters.DjangoFilterBackend,)
but would that be the cause of the issue? we will remove it, but it seems
unlikely.
Any ideas where we should debug or profile?
when I mock the request and render the JSON manually, I get a response in
677[ms], this includes getting the queryset 757[microseconds] and
serialization 57[microseconds], so this is what we expect. Also our
previous API which is ASP.NET + MSSQL is about 600[ms] roundtrip.
Thanks again!
On Wednesday, January 11, 2017 at 1:00:56 AM UTC-8, Xavier Ordoquy wrote:
>
> Hi,
>
> It’s likely either the displayed filter or the create/update form from the
> browsable API that spans some relation and gets the UI slow.
> Try to perform the same request as JSON that should validate the previous
> assomption.
>
> Regards,
> Xavier Ordoquy,
> Linovia.
>
> Le 11 janv. 2017 à 09:20, Mark Mikofski <[email protected] <javascript:>>
> a écrit :
>
> We are experiencing very slow performance from one view in the API that
> returns a queryset of a filter. We expected 0.5 - 1.0 sec, but the request
> is taking up to 4 seconds. Turning off pagination decreases the wait to 2
> sec.
>
> From the Django shell, the query is extremely fast, < 0.001 sec.
>
> >>> from django.db.models import F
> >>> from app.models import Weather
> >>> import numpy as np
> >>> R_EARTH = 6371000.0 # [m] earth's radius
> >>> search_radius = 160934
> >>> latitude, longitude = 38.1, -122.1
> >>> dtheta = np.rad2deg(search_radius / R_EARTH) # [degrees]
> >>> queryset = Weather.objects.filter(
> ... latitude__range=(latitude - dtheta, latitude + dtheta),
> ... longitude__range=(longitude - dtheta, longitude + dtheta),
> ... data_type__in=Weather.ALL_DATA_TYPES
> ... ).annotate(distance_d=(
> ... (F('latitude') - latitude) ** 2 + (F('longitude') - longitude) **
> 2)
> ... ).order_by('distance_d').exclude(distance_d__gt=(dtheta ** 2))
> # 1000 loops, best of 3: 737 µs per loop - using %timeit
>
> I tested serializing the queryset and rendering the response, and It is
> still very fast, < 1 sec
>
> # I know there is an easier/better way to do this, sorry :(
> >>> from django.http import HttpRequest
> >>> from rest_framework.request import Request
> >>> from app.serializers import WeatherSearchSerializer
> >>> request = Request(HttpRequest())
> >>> request.META['SERVER_NAME'] = u'localhost'
> >>> request.META['SERVER_PORT'] = 8000
> >>> w = WeatherSearchSerializer(queryset, context={'request': request},
> many=True)
> # 10000 loops, best of 3: 56.5 µs per loop - using %timeit
> >>> jsondata = JSONRenderer().render(w.data)
> # 1 loops, best of 3: 677 ms per loop - using %timeit
>
> But if I use the browseable API or send a request, it takes 3-4 seconds.
>
> >>> import requests
> >>> PARAMS = {'latitude': 38.2, 'longitude': -122.1}
> >>> requests.get(url=URL, auth=AUTH, params=dict(PARAMS, limit=1000))
> # 1 loop, best of 3: 4.21 s per loop - using %timeit
>
> requirements:
>
> Django>=1.8.5
> djangorestframework>=3.3.3
> psycopg2>=2.6.2
> django-storages>=1.4
> boto>=2.38.0
> django-crispy-forms>=1.6.0
> django-filter>=0.14.0
>
>
> platform: AWS
> EC2: c3.4xlarge instance based on Oracle Linux 7.2
> RDS: Postgres on a db.m3.medium instance with 1TB of storage
> S3
> software: Apache httpd with mod_wsgi and python-2.7
>
> models and serializers: totally vanilla, nothing custom
> * serializer is `serializers.HyperlinkedModelSerializer`
>
> views: totaly vanilla, nothing custom
> * view uses `viewsets.ModelViewSet`
>
> Any ideas where the extra seconds are coming from? I'm not sure where to
> profile. Any assistance would be greatly appreciated.
>
> Other relevant posts:
> *
> https://groups.google.com/d/msg/django-rest-framework/AkLKdfxCrcU/qyOB1k37pJAJ
> * that's all I could find search terms: slow queryset
>
>
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