# Phase 4 — Future / optional

**Status:** ❄️ Not committed

Ideas on radar that may or may not become real tasks. Captured here so they don't get forgotten and so we have a place to push scope creep that surfaces during Phase 1–3.

## Candidates

- **Directus Flow trigger emission.** When a domain event fires (timing record written, stage result computed, anomaly detected), publish a structured event Directus Flows can subscribe to. Lets Directus orchestrate notifications, integrations, derived workflows without polling the database.

- **Replay tooling.** Read historical positions for a device + time range from Postgres, re-emit them through the domain pipeline (geofence engine, timing logic) without touching `positions`. Useful for: validating a new geofence layout against past races, regenerating timing records after a rule change, demoing.

- **Derived-metric backfill.** When the IO mapping table changes (new model, corrected mapping), backfill `decoded_attributes` for affected devices over a chosen time range without touching `positions`.

- **Alternate consumer for analytics export.** A second consumer group reading the same stream, writing to a parallel destination (Parquet on object storage, ClickHouse, etc.) for offline analytics. The Phase 1 architecture already supports this — it's a separate process joining the same stream with a different group name. No Processor changes needed; just operational scaffolding.

- **WebSocket gateway for live updates.** If Directus's WebSocket subscriptions hit a fan-out ceiling for spectator-facing live leaderboards, a dedicated gateway reads from Redis and pushes to clients, bypassing Directus for the live channel only. REST/GraphQL stays in Directus. Mentioned in `wiki/entities/directus.md`.

- **Per-instance sharding hint.** If consumer-group load distribution turns out to be uneven (one instance handles all the chatty devices), introduce hashing-by-device-id with explicit assignment. Probably overkill — Redis Streams' default round-robin works for most workloads.

None of these are committed. Move them out of Phase 4 and into a numbered phase only when there's a concrete reason to do them.