This is where NodeJS really starts to shine - persistant connections and background operations let you do a whole bunch of cool stuff to mitigate that.
In my case I have entire db tables and collections replicated in memory and kept in sync via redis pubsub, and the 100,000s of concurrent users I have are all sharing just a few dozen persistant redis and mongodb connections between them.
In my case I have entire db tables and collections replicated in memory and kept in sync via redis pubsub, and the 100,000s of concurrent users I have are all sharing just a few dozen persistant redis and mongodb connections between them.