Django: Performance Wins with Smarter QuerySets

Today we're diving into a fascinating performance optimization that landed in Django core - a new private API for preventing QuerySet cloning that could speed up your database operations. Felix Maksimov merged a clever solution that uses custom context managers instead of decorators to squeeze out microseconds of performance.

Duration: PT3M55S

Episode overview

This episode is a short developer briefing from Django.

It explains recent repository work in plain language.

  • Show: Django
  • Published: 2026-03-12T10:03:34Z
  • Audio duration: PT3M55S

Transcript excerpt

This excerpt keeps the crawler page concise. Listen to the episode or use the RSS feed for the full update.

Hey there, Django developers! Welcome back to another episode. I'm your host, and wow, do I have an interesting story for you today from the Django codebase. Grab your favorite beverage because we're talking about one of those under-the-hood improvements that might not make headlines but could genuinely make your…

So yesterday, Felix Maksimov merged a really thoughtful pull request that implements private API methods for preventing QuerySet cloning. Now, I know that sounds super technical, but stick with me because this is actually a beautiful example of performance engineering done right.

Here's the story: Django's QuerySets are immutable by design, which is fantastic for safety and predictability. Every time you chain a filter or an annotation, you get a fresh QuerySet clone. But sometimes, especially in Django's own internals, this cloning behavior can create unnecessary overhead. Felix tackled…

The implementation introduces methods to temporarily disable QuerySet cloning when it's safe to do so. Think of it like putting your QuerySet into a special mode where it says "hey, I trust you, let's skip the copying for a bit." The API works as a toggle - multiple calls to disable…

But…

No…

Nearby episodes from Django

  1. Better Error Handling & Database Fixes
  2. Test Fixes and Documentation Cleanup
  3. Polish & Performance - Small Fixes, Big Impact
  4. Security Hardening and Community Care
  5. Better Docs and Smarter Error Handling
  6. Signals Clarity and Streaming Performance
  7. Streaming, Signals, and Small Wins
  8. Migration Fixes and Speed Wins