Django - rendering many templates using templatetags is very slow

Question

Say, I have a page with a photo gallery. Each thumbnail has e.g. a photo, country, author and so on. I render these items/widgets using template tags (which load specified templates) - it goes that way because of DRY (I use these items/widgets separately in different places on the page).

And it is very slow.

I have performed some profiling using django-debug-toolbar:

SQL Queries: default 84.81 ms (147 queries)

But:

Total CPU time: 5768.360 msec

Which is too long to wait.

After some analysis it turned out that the main culprit is templating enginge.

When I want to display e.g. 150 photos, 600 associated items/widgets are being rendered via templates. It means 600 I/O operations or even more. Moving these widgets to main template solves the problem, but does not keep DRY.

So my question is how one can avoid such a behaviour? Be DRY and slow or no-DRY and fast? I'd rather be DRY and fast...

Answer 1

After several hours of profiling and searching...

Thanks for your help, but in this case it seems to me that the best solution so far is to use Template fragment caching:

I tried it and gained 70-80% speed performance!

{% load cache %}
{% cache 3600 mywidget_id %}
    .. rendered mywidget is cached ..
{% endcache %}