Why is my Django site slow?

Diagnosing Django Performance Bottlenecks

When we analyze slow Django sites at HostingDuty, we typically find three root causes: inefficient database queries, missing caching layers, or server resource constraints. The most common issue is the N+1 query problem where Django executes one query per object instead of batching them.

Database Query Optimization

Django's ORM can generate excessive SQL if not used carefully. Use select_related() for foreign key relationships and prefetch_related() for many-to-many relationships to reduce query count. Enable the Django Debug Toolbar in development to identify slow queries:

``python INSTALLED_APPS = [ 'debug_toolbar', # ... other apps ] `

For production, implement query logging to track execution times. We recommend checking our /kb/django-query-optimization guide for detailed strategies.

Caching Implementation

Static content and database query results should be cached. Redis is our preferred cache backend at HostingDuty. Configure it in settings.py:

`python CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.redis.RedisCache', 'LOCATION': 'redis://127.0.0.1:6379/1', } } ``

See our /tutorials/django-redis-caching tutorial for step-by-step setup.

Server Resource Monitoring

Check CPU, memory, and disk I/O metrics. Slow disk I/O often indicates database indexing issues. We monitor these metrics using our /qa/django-performance-monitoring FAQ for best practices.

External Resources

For deeper performance analysis, consult the official Django documentation on performance optimization and the SQLite vs PostgreSQL comparison for database choices.