Lazily import django.test to reduce import time

[angusholder]

I was running a flamegraph on our manage.py, and noticed this import of django.test using 20-40ms. Seems like an easy win for startup time to make it a lazy import, because most production code wouldn't normally ever need the django.test module.

[adamchainz]

Thanks, that is an easy win. I added a changelog note and improved the comment.

This function could be improved further to not use django.test and instead capture the query with database instrumentation, if you’re up for the challenge.

[angusholder]

After sending this, I realised it was your blog posts I read recently about improving Django start time, so thanks for those!

Might have a go at that database instrumentation change later, I haven't seen it before, looks interesting.

[adamchainz]

Glad you enjoyed them!

I also have some blog posts on database instrumentation that may inform: https://duckduckgo.com/?t=ffab&q=site%3Aadamj.eu+%22database+instrumentation%22&ia=web

The suggestion is just an “if you’re interested”, I don't use pt_visual_explain myself, at the moment, and I guess you don’t either :)