We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%.

Measure. Don't tune for speed until you've measured, and even then don't unless one part of the code overwhelms the rest.

We spend a lot of our time in the modern, web services-driven technology industry ignoring performance issues. What's the point of micro-optimizing a 3ms function call when each request spends 8 or 9 seconds inside the SQLAlchemy ORM? Well, sometimes it's nice to …