I don't see how the scenario with a single customer ID is credible. Why not just put a cache in front of the db? Now there is even a fully managed solution for

I don't see how the scenario with a single customer ID is credible. Why not just put a cache in front of the db? Now there is even a fully managed solution for that: https://aws.amazon.com/dynamodb/dax/ https://aws.amazon.com/dynamodb/dax/