Radix Technical AMA with Founder Dan Hughes – 2nd February 2021

Regarding the Cerberus implementation: Will contracts (state machines) have access to the quorum certificate of a command?

All state transitions require a quorum of agreement or rejection. A Quorum Certificate will be available at all validators that execute any state transitions within the atom, for all state transitions within the atom. A contract will be executing and invoking state transitions, so yes, it stands to reason that it will have access to the output certificates from those transitions.

A cross-shard transaction must be processed by multiple nodes at the same time. Is there a risk of starvation for a transaction involving busy shards? How are transactions in the same shard prioritized?

This is possible if there is no mechanism to provide some guard against it. The solution will likely be validators that weakly sync their mempools with other validators on shared events and use a priority queue to ensure that all validator sets process any atom in question at around the same time. This is something I’ve recently developed and is implemented in the Cassandra research platform, and it works wonderfully in situations where there is an uneven load or high latencies 😊.