ADR-0005: Full time model in the first milestone set

Status: Accepted (2026-07-15)

Context

Time-travel views (as-of, since, history), the log API, and tx-report queues could ship incrementally after a current-view-only v1. But the datom (tx, added) fields and the durable log must exist from the start regardless — the question is only whether the views are exposed.

Decision

M3 exposes the complete time model: as-of, since, history database views, tx-range/log access, sync, and tx-report queues. History index variants are maintained by the same indexing pass as current indexes from M2. Excision is explicitly excluded (design space reserved in time-model.md).

Consequences

• Index design must settle history-retention rules early (retraction pairs, :db/noHistory), avoiding a later reindex-the-world migration.
• Marginal cost over a current-only v1 is mostly in the query layer's view plumbing and conformance vectors — the storage cost is paid either way.
• Storage growth is unbounded by default (as in Datomic); :db/noHistory and (later) excision are the pressure valves, and GC only collects unreachable segments, not history.