In my experience it's really hard to prevent issues like this. RDBMS's kind of push you to keeping everything in the same database to take advantage of foreign

In my experience it's really hard to prevent issues like this. RDBMS's kind of push you to keeping everything in the same database to take advantage of foreign keys and other features when in reality different data types will need their own source of record. I consider myself more experienced than most and I still fell into this trap in recent memory, failing to expect the scaling requirements for one of my tables until it was too late.