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The Django ORM Deep Dive
The Performance Knowledge That Separates Junior Developers from Senior Engineers
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I once watched a senior developer cut a page load time from 12 seconds to 200 milliseconds.
No caching. No infrastructure changes. Just three lines of code.
The problem? The original code was making 847 database queries to load a single page. The fix used select_related and prefetch_related correctly.
This is the knowledge gap that separates developers who write Django code from developers who write fast Django code. The ORM makes it dangerously easy to write queries that work perfectly in development with 100 rows, then collapse in production with 100,000 rows.
Today, I’ll show you how to identify and fix the most common ORM performance killers — especially the infamous N+1 problem.
Let’s make your queries fast.
The N+1 Problem Explained
The N+1 problem is the most common performance issue in Django applications. Here’s what it looks like:
# models.py
class Author(models.Model):
name =…
