> No Schema upgrades (This one is massive for me) At Amazon, relational databases are banned unless you get an explicit exemption from senior leadership. This

> No Schema upgrades (This one is massive for me) At Amazon, relational databases are banned unless you get an explicit exemption from senior leadership. This is the primary reason why. Too many cases of schema upgrades causing outages. The problem with DDB or other NoSQL applications, like you say, is how much you need to consider your query patterns. The last major project I worked on using DDB, we spent a couple of days just thinking through our query patterns so we could come up with the right database design and data structures. (We still believe it was the right choice, though.)