91–95 of 95 posts
Earlier quoted context omitted.
Time synchronization over a network with unknown latency characteristics is fundamentally impossible.
Drop the “over a network with unknown latency characteristics” - it’s cleaner
The two papers mentioned in the post are highly insightful. This is one of my favorite subjects.
To fully disclose, I have a biased view on this given that I work for a (closed source) serverless, no-ops DB provider (Fauna) that implements a distributed transaction engine that is natively document-relational and doesn't compromise on relational (ACID, transactional) guarantees.
Ethereum rollups have proven that transactions can scale
The important parts: > The data is assumed to be randomly distributed to memory nodes in the shared memory pool. Any memory node is equi-distant to any compute node, and a compute node needs to reach multiple memory nodes for transaction execution. and also: > Once a memory server fails, NAM-DB halts the complete system and recover all memory servers to a consistent state from the last persisted checkpoint. The recov…
distributed transactions that can assume fast and reliable access to some shared memory are interesting but really the easy part of the problem
"scale" means going across large physical distances where neither low latency nor high availability can be assumed, so not in a single datacenter where nodes are connected by infiniband or whatever
Earlier quoted context omitted.
Drop the “over a network with unknown latency characteristics” - it’s cleaner
Cleaner perhaps, but wrong. If you know that latency is statistically symmetrical (same in both directions, on average) then you can synchronize clocks to arbitrary precision (asymptotically at least).
My understanding of relativity is that this is principally unknowable and we only assume that speed of light is same in every direction by convention (every few years there’s a paper that claims they managed to measure one way sol but later it turns out they actually measured two-way in a roundabout way) so you can’t really know that?