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.

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dotancohen 2 hours ago | parent [-]

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

	▲	aurareturn an hour ago \| parent [-]
		It was one of the top real estate portals in the world. A lot of geolocation searches. New search every time someone moves the map. A ton of data sent to the client. Analytics in every page view. No clue how a shopping cart or checkout flow would drastically increase database load. It should just be basic CRUD. Building a shopping cart is something every student makes. Pages in a web store can be cached relatively easily since items won't change often. A primary DB with a few replicas and caching can go a really long way.