[throwawaythekey]

>I would've expected the candidate to at least be able to talk about indexing, tradeoffs of joining in the DB vs. in the application, schema migrations and upgrades, creating separation between data-at-rest vs. data-in-flight, etc.

The problem is that many of these trade-offs only applied to older databases. The more relevant axis is about how distributed the db is, the replication type etc.