Realtime active users with high traffic help

schema
influxdb

#1

I have a system where I have like ~100k users/hour and growing. I was storing userId as a tag to calculate the unique active users in every hour (with a Continuous Query) but today I’ve found it’s not recommended to have a lot of unique tag values.

How do you think I could improve this? Think on Google Analytics real-time active visitors like functionality.