At a given point in time yes, but to get this data set, you need to write it into the DB. Big datasets implies either you have been receiving data for very long

At a given point in time yes, but to get this data set, you need to write it into the DB. Big datasets implies either you have been receiving data for very long of you did it quickly on a shorter period of time. It's usually the later. Which mean you need fast writes. 50 writes / sec is terrible, even more if to improve that you need to buy more servers while you 30 euros / months postgres instance can deal much more than that.