Stop Tilting at Windmills: Spotting Bottlenecks

Presented by Yann Malet & Brandon Konkle

Get numbers before you start trying to debug. You can’t fix a problem you don’t have.

Performance Testing

• Time to load a page
• Number of queries per page
• Time taken by the queries
• Number of cache hits/misses
• Time spent waiting on 3rd parties

Note

Django Debug Logging: https://github.com/lincolnloop/django-debug-logging

Load Testing

• Taking your entire app infrastructure into account
• Understanding how your performance changes under stress and over time
• Creating realisting test plans that imitate real life traffic

Database

• Handling numerous queries in parallel
• Types of queries running at the same time

Caching

• Cache key expiration
• Cache size and key eviction

Note

JMeter

Command-line tools

• htop
• dstat
• pg_top, mtop
• memcache-top