Replicated Logs

Honest by Construction

committedIndex, divergence, and repair are recomputed before rendering.

highlighted = computed this step

Honest by construction

The author supplies node logs and optional expected facts. The engine recomputes committedIndex, follower match facts, divergence, and repaired logs before rendering. Note: expected facts can reject a mismatch but cannot create the answer.

recompute boundary\text{recompute boundary}

Compiled cluster

The compiled cluster has committedIndex 2 and 2 followers. Note: the render shows the cluster facts.

committedIndex=2,followers=2\text{committedIndex}=2,\quad \text{followers}=2

a simplified leader-based log replication; quorum commit + log repair are exact on these tiny clusters; full Raft safety, leader election (next book), and network partitions/timing are beyond these traces - no product claims.

Honest replication - quorum 2; committedIndex 2; divergent: F2nodeidx 1idx 2idx 3Lt1:at2:bt2:cF1t1:at2:bF1 repairt1:at2:bt2:cF2t1:at1:xF2 repairt1:at2:bt2:c

Wrong result reject

A wrong expected committedIndex is rejected during the lesson self-test. Note: the rejection happens before an inconsistent diagram can publish.

reject mismatch\text{reject mismatch}

Summary

Replication lessons are honest because commit, divergence, and repair are recomputed from the logs. Note: this is simplified leader-based replication; full Raft safety and leader election are the next book, while partitions and timing are beyond these traces.

honest replication\text{honest replication}