[nrjdhsbsid]

That's only 1000 messages per second on average. A single database +app server could handle that load. Assuming a bunch of other stuff is happening 500 servers sounds generous.

Wtf are they doing that each server can only handles one tweet every two minutes?

[burgreblast]

Actually, it's 1000-9000 messages per server per day. Or about 1 message every 10-100 seconds.

Of course, that's just the new messages inbound. They may need to distribute that single message to 100M people (who likely won't even see it, but still.)

Problems that are trivally solvable with one database don't simply scale by adding more DBs or machines. Scaling isn't easy or they would have done it. I'm in no way disparaging their team, because I don't know what kind of constraints they had getting to this point.

Still, I'd bet it could be optimized by 2+ of orders of magnitude if people sat down and re-evaluated the whole structure again at this point in time.

Regardless, is that really a priority?

They may have bigger issues on their plate now (growing revenue, growing users, making users happy). Assuming their business can generate the cash flow to overcome the inefficiencies, they may be better served to focus on growth.