Django urlconf performance: will nested pattern groups help or hurt?

Question

I'm wondering if restructuring my apps' urlconfs with several nested pattern groups will provide a performance boost for when Django looks for a request-matching pattern. I'm not sure on how to test the performance, but I've tried it out and the new version works at least.

I know that if there is a performance boost, it may as well be negligible. I only started doing this to see if the patterns would be easier to look at as a tree; I'm more worried about screwing things up than boosting speed.

The following is an app's urlconf that is included by the master urlconf at /appname/.

Old urlconf:

from django.contrib.auth.decorators import login_required
from django.conf.urls.defaults import patterns, include, url
from django.views.generic.simple import redirect_to

from appname import views

urlpatterns = patterns('',
    # Actions on sets of reports
    url(r'^reports/page(?P<page>[0-9]+)/$', login_required(views.appnameListView.as_view())),
    url(r'^reports/bill/', views.bill),

    # Actions on individual reports
    url(r'^report/new/', views.new),
    url(r'^report/(?P<reportNumber>[^/]+)/$', views.detail),
    url(r'^report/(?P<reportNumber>[^/]+)/delete/$', views.delete),
    url(r'^report/(?P<reportNumber>[^/]+)/edit/$', views.edit),
    url(r'^report/(?P<reportNumber>[^/]+)/print/$', views.detail_print),
    # url(r'^report/(?P<reportNumber>[^/]+)/pdf/$', views.detail_pdf),

    # Configure app settings
    url(r'^config/$', views.configure),
    url(r'^config/reporttype/(?P<id>[^/]+)/$', views.configure_ReportType),
    url(r'^config/reporttype/(?P<id>[^/]+)/delete/$', views.configure_ReportType_delete),
    url(r'^config/avgmethod/(?P<name>[^/]+)/$', views.configure_AvgMethod),
    url(r'^config/avgmethod/(?P<name>[^/]+)/delete/$', views.configure_AvgMethod_delete),
    url(r'^config/datatransformer/(?P<name>[^/]+)/$', views.configure_DataTransformer),
    url(r'^config/datatransformer/(?P<name>[^/]+)/delete/$', views.configure_DataTransformer_delete),

    # Catch all; #TODO: 404
    url(r'^', redirect_to, {'url': '/appname/reports/page1/'}),
)

New urlconf:

from django.contrib.auth.decorators import login_required
from django.conf.urls.defaults import patterns, include, url
from django.views.generic.simple import redirect_to

from appname import views

urlpatterns = patterns('',
    # Actions on sets of reports
    url(r'^reports/', include(patterns('',
        url(r'^page(?P<page>[0-9]+)/$', login_required(views.appnameListView.as_view())),
        url(r'^bill/', views.bill),
    ))),

    # Actions on individual reports
    url(r'^report/', include(patterns('',
        url(r'^new/', views.new),
        url(r'^(?P<reportNumber>[^/]+)/$', views.detail),
        url(r'^(?P<reportNumber>[^/]+)/delete/$', views.delete),
        url(r'^(?P<reportNumber>[^/]+)/edit/$', views.edit),
        url(r'^(?P<reportNumber>[^/]+)/print/$', views.detail_print),
        # url(r'^(?P<reportNumber>[^/]+)/pdf/$', views.detail_pdf),
    ))),

    # Configure app settings
    url(r'^config/', include(patterns('',
        url(r'^$', views.configure),
        url(r'^reporttype/(?P<id>[^/]+)/$', views.configure_ReportType),
        url(r'^reporttype/(?P<id>[^/]+)/delete/$', views.configure_ReportType_delete),
        url(r'^avgmethod/(?P<name>[^/]+)/$', views.configure_AvgMethod),
        url(r'^avgmethod/(?P<name>[^/]+)/delete/$', views.configure_AvgMethod_delete),
        url(r'^datatransformer/(?P<name>[^/]+)/$', views.configure_DataTransformer),
        url(r'^datatransformer/(?P<name>[^/]+)/delete/$', views.configure_DataTransformer_delete),
    ))),

    # Catch all; #TODO: 404
    url(r'^', redirect_to, {'url': '/appname/reports/page1/'}),
)

I could go even further (4 of the 5 variables checked for with regex are defined at least twice), but I worry about losing the original benefit of readability.

as you said, if there is a speed improvement it is negligible. there seems to be no question here. everyone knows that if you need to improve performance it is better to spend time looking at database queries. :) — akonsu, Jan 24 '12 at 03:24

score 2 · Accepted Answer · answered Jan 24 '12 at 16:19

2

If you do not want to reapeat yourself and follow the DRY-principle, which is sometimes incorporated a lot when developing django code, you should group your urls. So you will reduce the amount duplicate code and produce code that is much easier to maintain. Think for example about the fact, that later on you may want to change the report/ urls to something else, you would have to do it for every single url then!

answered Jan 24 '12 at 16:19

Bernhard Vallant

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Very true, just keep in mind: [Cool URIs don't change](http://www.w3.org/Provider/Style/URI)! ;) – Jan Pöschko Jan 24 '12 at 16:25
@JanPöschko: Well was thinking about adding that too, but there can be also a lot of URLs for admin uses etc which might change due to a changed functionality of the site :) And furthermore, because you mention URIs: If you _group_ your URLs you will get much easier and better insight in what patterns belong to what ressource... – Bernhard Vallant Jan 24 '12 at 17:41

Django urlconf performance: will nested pattern groups help or hurt?

1 Answers1