Traditionally, metrics are performed by a batch job (running hourly, daily, etc.). Redis backed bitmaps allow us to perform such calculations in realtime and are extremely space efficient. In a simulation of 128 million users, a typical metric such as “daily unique users” takes less than 50 ms on a MacBook Pro and only takes 16 MB of memory. Spool doesn’t have 128 million users yet but it’s nice to know our approach will scale. We thought we’d share how we do it, in case other startups find our approach useful.
A very different approach to the classical approach of historical event logging.
Original title and link: Redis Bitmaps for Real-Time Metrics at Spool ( ©myNoSQL)