100? I had a customer with 10k upserts incl merge logic for the upserts while serving 100k concurrent reads. Good luck doing that with a SQL database trying to check constraints across 10 tables. This is what Nosql databases are optimized for...
There's some stand-out examples of companies scaling even mysql to ridiculous sizes. But generally speaking, relational databases don't do a great job at synchronous/transactional replication and scalability. That's the trade off you make for having schema checks and whatnot in place.
I guess I didn't make myself clear. The number was supposed to be trivially low. The point was that "high performance" is like the least important factor when deciding on technology in my context.