Truth Plane / Acceleration Plane
Some data must be absolutely correct; the system must also be fast. Make exactly one store authoritative (the Truth Plane) and treat caches/counters as a disposable Acceleration Plane rebuildable from it. Prevents drift, races, and inconsistent business decisions — the canonical realization of Law I in a product.
Problem
Large platforms need speed, aggregation, counters, discovery, and read models. Some facts still must remain absolutely correct: ownership, money, rights, identity, access, verification, and enforcement. If every fast store becomes equally authoritative, the system eventually drifts.
Context
Use this pattern when the product has authoritative business facts and also needs fast derived data: caches, counters, analytics, recommendation inputs, discovery indexes, or precomputed views.
Forces
- Correct business facts must survive retries, races, rebuilds, and partial outages.
- Fast reads want local, denormalized, or precomputed structures.
- Caches and projections fail, lag, and lose data.
- Teams under pressure tend to answer business questions from the fastest place.
Solution
Name one Truth Plane for authoritative facts. Treat acceleration structures as derived, rebuildable, and disposable. The Acceleration Plane may make the product faster; it may not decide ownership, money, rights, access, verification, or enforcement.
Consequences
Developers know which datastore can answer which question. Derived systems can be rebuilt without data loss. Failure modes become safer because stale acceleration affects freshness or speed, not truth.
Failure Modes
- A cache value becomes the only copy of a business fact.
- A counter is corrected by hand without correcting the source record.
- A fast read model starts answering permission or settlement questions.
- A rebuild cannot reconstruct the acceleration layer from truth.
Proof Points
and recommendations derive from it.
- Ampriot — MariaDB owns truth; Redis, analytics, graph,
Full source pattern: 01-truth-plane-acceleration-plane.md.