django url tag performance

Question

I was trying to integrate django-voting into my project following the RedditStyleVoting instruction.

In my urls.py, i did something like this:

    url(r'^sections/(?P<object_id>\d+)/(?P<direction>up|down|clear)vote/?$',
    vote_on_object,
    dict(
        model=Section,
        template_object_name='section',
        template_name='script/section_confirm_vote.html',
        allow_xmlhttprequest=True
        ),
    name="section_vote",

then, in my template:

    {% vote_by_user user on section as vote %}
{% score_for_object section as score %}

<form class="sectionvote" id="sectionup{{ section.id }}"{% if vote and vote.is_upvote %} action="{% url section_vote object_id=section.id, direction="clear" %}"{% else %} action="{% url section_vote object_id=section.id, direction="up" %}"{% endif %} method="POST">
<input type="image" id="sectionuparrow{{ section.id }}" src="{{ MEDIA_URL }}/aup{% if vote and vote.is_upvote %}mod{% else %}grey{% endif %}.png"></form>

{{ score.score|default:0 }}

<form class="sectionvote" id="sectiondown{{ section.id }}"{% if vote and vote.is_downvote %} action="{% url section_vote object_id=section.id, direction="clear" %}"{% else %} action="{% url section_vote object_id=section.id, direction="down" %}"{% endif %} method="POST"> 
<input type="image" id="sectiondownarrow{{ section.id }}" src="{{ MEDIA_URL }}/adown{% if vote and vote.is_downvote %}mod{% else %}grey{% endif %}.png"></form>

It takes over 1.3s to load the page, but by hard coding it like this:

<form class="sectionvote" id="sectionup{{ section.id }}"{% if vote and vote.is_upvote %} action="sections/{{section.id}}/clearvote/"{% else %} action="sections/{{section.id}}/clearvote/"{% endif %} method="POST">

<form class="sectionvote" id="sectiondown{{ section.id }}"{% if vote and vote.is_downvote %} action="sections/{{section.id}}/clearvote/"{% else %} action="sections/{{section.id}}/downvote/"{% endif %} method="POST"> 

I got 50ms. Just avoid the url tag resolving stuff I got a 20+ times performance improvement. Is there something I did wrong? If not, then what's the best practice here, should we do things the right way or the fast way?

Answer 1

If you're using the development version, there has recently been a regression which has massively increased the time it takes to reverse-lookup URLs - see the ticket here. It is scheduled to be fixed before the final release of 1.2.