pub trait BoundedRecovery { }Expand description
Assumption (Bounded recovery). After GST, a correct validator that crashes restarts and is again answering requests within Δ.
CorrectValidator admits a crash at any moment, discarding whatever was not persisted.
Before GST that is unconstrained: crashes may be arbitrarily frequent and restarts arbitrarily
slow, which is one of the ways the network is allowed to misbehave. After GST it must stop,
or CorrectValidatorAvailability is unattainable — a validator that restarts more slowly
than Δ is, from the protocol’s point of view, permanently unavailable.
What the implementation must do to earn this is bounded work on restart: reload the chain
views from storage rather than replay history. That holds for a validator that was only
briefly down, since its saved state is close to the tip. It does not hold for one that has
fallen far behind, where catching up is linear in the distance to the chain’s latest
checkpoint — see BoundedCatchUp, which is where this assumption’s real cost sits.