[philjohn]

Yes, but your clustering is just read-only replicas. So you still have the problems that when your graph gets huge and you run out of space to scale each node up you're going to have a bad time. And it also ignores that when you're talking about scaling up to truly monstrous machines with TB of memory the cost is astronomical.

I agree, it's not an easy problem to solve, but saying nobody has solved it isn't accurate either - OpenLink (who I mentioned previously) solved it for their RDF engine. At a previous gig using that across an 8 node cluster we were seeing load rates of hundreds of thousands of edges (or in this case, quads) per second.