[willdr]

You don't see how adding functionality that requires writing to the database rather than just reading from a cache could "drastically increase database load"?

[aurareturn]

Even if it's writing to the DB, I doubt basic queries like adding an item to a cart is going to need DB sharding.

I think one piece that someone else mentioned could require DB sharding and that is all the live data needed for tracking deliveries.

The actual website/app should not need more than one beefy Postgres instance.