Amazon does 20k peak, or 20k average? Website visitor peaks could easily be two orders of magnitude higher traffic than average for a few minutes.

[deleted]

I worked at a company that had billions of views per year on a single big Postgres instance. Extremely read heavy with many queries needed for a page load. You can cache a lot of things.

Yes, but that's not a shopping cart, or a checkout workflow, nor a web store with heavy analytics.