Serializability

Honest by Construction

Edges, cycle, verdict, and topo order are recomputed before rendering.

highlighted = computed this step

Honest by construction

The author supplies a schedule and optional expected graph facts. The engine recomputes edges, cycle, verdict, and topo before rendering. Note: expected facts can reject a mismatch but cannot create the answer.

recompute boundary\text{recompute boundary}

Compiled schedule

The recomputed edge count is 2 and cycle length is 2. Note: the verdict is rendered from those facts.

edges=2,cycle length=2\text{edges}=2,\quad \text{cycle length}=2

conflict-serializability is an exact SUFFICIENT criterion; a cyclic precedence graph is provably not conflict-serializable; view-serializability, lock scheduling, and recovery are beyond these tiny traces - no product claims.

Honest schedulestepT1T20R(A)1W(A)2W(B)3W(B) conflict-serializable: no; cycle: T1,T2T1T2

Wrong verdict reject

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

reject mismatch\text{reject mismatch}

Summary

Schedules are honest here because graph facts are recomputed from the operation trace. Note: conflict-serializability is exact here; view-serializability, locks, and recovery are deferred.

honest schedules\text{honest schedules}