WhatsApp and twitter’s latency calculations are on different things.
Twitter’s latency stems from calculating what tweets should show on a given request. Even if you try to show tweets from 1 minute ago, it’s hard to cache that stuff using traditional systems because of the fan out. If an account with 50 million followers tweets, you need to update 50 million timelines. How do you do that quickly?
And you would have to define maximum latency, is it seconds, minutes, hours? because you can’t have the timelines be inconsistent for too long as that leads to some people getting news faster than others.
Twitter’s latency stems from calculating what tweets should show on a given request. Even if you try to show tweets from 1 minute ago, it’s hard to cache that stuff using traditional systems because of the fan out. If an account with 50 million followers tweets, you need to update 50 million timelines. How do you do that quickly?
And you would have to define maximum latency, is it seconds, minutes, hours? because you can’t have the timelines be inconsistent for too long as that leads to some people getting news faster than others.