Load balancers, microservices and horizontal scaling?

Looks like the GIF is fully built out in code. It's really nice to look at, well made, and easy to understand too. I wonder what program or code they used. I'd love to know.

p.sI thought it was a GIF, but it's an iframe. That was a nice little surprise.

Previously: https://news.ycombinator.com/item?id=48925420

What about sequences? The example shows an auto-incrementing user ID. How’s that possible without contention between all shards? Is the proxy responsible for sequences?

What about foreign keys? Do they all have to live on the same shard? How do you do distributed transactions?

On cross-shard reads: how do you do sorting? And cross-shard joins?

I’d love to be proven wrong, but I suspect the 768 servers look like 1 only on the very surface, and you’ll get wildly different characteristics from cross-shard and single-shard queries.

I personally would prefer if they _didn’t_ look like 1 if they can’t behave like 1.