[nevi-me]

It has most of that. It's not that RDBMS are hard and schemaless convolutions are easier.

Mongo has query planners, the same thinking you do in SQL applies to Mongo, the edge cases are different. For example, you can't have composite indices on multiple arrays. The same principles we consider when tuning our RDB apply to Mongo, normalisation comes at different forms/levels. The same applies to denormalisation. Just because there are/were "no joins" didn't mean that everything goes into a single collection.

I run some Mongo deployments, and I take as much care in understanding performance, as I do with our SQL deployments. Databases are hard to those who are unwilling to open up the manual and read. It's not only SQL.