Comment by wyager

Why use Redis and multiple machines instead of keeping it in RAM on a single machine? I'm not claiming the Reddit people did anything wrong; they have a lot more experience than me here obviously. I'm just trying to figure out why they couldn't do something simpler. 333 updates/sec to a 500kB packed array, coupled with cooldown logic, should have a negligible performance cost and can easily be done on a single thread. That thread could interact via atomic channels with the CDN (make a copy of the array 33 times a second and send it away, no problem) and websockets (send updates out via a broadcast channel, other cores re-broadcast to the 100K websockets). Again, I'm not saying this is actually a better idea, this is just what I would do naively and I'm curious where it would fall apart.