A couple of weeks ago I went to Google to attend a talk about Firebase and in the talk they advised to not use Firebase for storing historical data like logs, stats and not actively changing datasets.
The advice from the speaker
It is usually a good idea to separate your active data from the historical data. If you’re only showing the last 30 days worth of data in your app, your application performance will be best if you put the older data in a different location from the active data. This doesn’t just apply to Firebase, nor even only to NoSQL solutions: even in SQL you see developers creating separate tables for active and for historical data. In Firebase this can be as simple as segmenting the data into month-based buckets.
The second point depends more on your needs. What I often see is that developers keep historical data to do reporting/analysis on. While it is definitely possible to do such analysis in Firebase, there are solutions that are more tailored to this use-case. BigQuery is a great example of such a solution as are many other analytics systems.
Do I need to setup a separate database in MySQL (I already master MySQL so it would be my first alternative) to store these data sets or would a Firebase database be good for the time being?