| name | 0.4.1-understand-consensus |
| description | [0.4.1] Agreement on a single value among a set of distributed processes; the core problem consensus protocols solve. |
understand-consensus
CALL NUMBER: distributed_consensus_and_replication_protocols.consensus : deep_raft(6)
DEFINITION: Agreement on a single value among a set of distributed processes; the core problem consensus protocols solve.
Invoke this skill to understand consensus down to its primitives. The RELATIVE ROOT below is the least-fixed-point closure of everything it bundles from — the full import cone, grouped by the lib each prim comes from. Projected from a prover-typed KB (MAP/SWI-Prolog consistency gate): every reference below resolves.
THE RELATIVE ROOT (the import cone, by lib)
from ?
- agreement (d1): The property that a set of distributed processes reach the same decision outcome on a given value. Uniform agreement requires all processes including those that later crash to decide identically; asymmetric agreement permits different decision classes for different process roles such as primary versus backup.
from deep_raft
- a007 (d1): Quorum in agreement: a subset of processes sufficient to guarantee agreement can be reached, typically intersecting any valid quorum to ensure overlap.
- a008 (d1): Threshold in agreement: the minimum number of correct processes required to guarantee safety and liveness under given failure assumptions.
- a009 (d2): Asymmetric agreement: one class of processes (e.g., primary) must agree while another class (e.g., backups) may reach different decisions, used in primary-backup protocols.
- a002 (d2): Validity in agreement: the decided value must have been proposed by some process in the system, guaranteeing agreements are grounded in actual proposals.
- a005 (d3): Uniform agreement: all processes including those that later fail must decide on the same value, stricter than ordinary agreement which only binds correct processes.
- a004 (d3): Termination in agreement: every correct process eventually decides some value, ensuring the protocol makes progress and does not stall indefinitely.
from distributed_consensus_and_replication_protocols
- fault_tolerance (d1): System's ability to continue operating correctly despite component failures.
- replicated_log (d2): Ordered log of commands maintained across replicas; foundation of state machine replication.
CONSUMERS (what needs this)
a005, a009, atomic_broadcast, causal_consistency, ft005, ft007, ft009, ft014, ft016, ft017, linearizability, lock_free, obstruction_free, paxos, raft, sequential_consistency, two_phase_commit, viewstamped_replication, wait_free, zab
Projected from the distributed consensus and replication protocols KB (196 concepts / 187 relations) — consistency-typed by MAP; the facet list after the colon IS the cross-lib dependency web.
(leaf — this is an actual skill.)
