As the author touches on, the main problem here isn't learning about indexes. It's about "infinity scaling" working <i>too well</i> for people who do not understand the consequences.<p>In no sane version of the world should "not adding a db index" lead to getting a 50x bill at the end of the month without knowing.<p>I am a strong believer that services that are based on "scale infinitly" really need hard budget controls, and slower-scaling (unless explicitly overidden/allowed, of course).<p>If I accidently push very non-performant code, I kind of expect my service to get less performant, quickly realize the problem, and fix it. I don't expect a service to seemingly-magically detect my poor code, increase my bill by a couple orders-of-magnitude, and only alert me hours (if not days) later.