Milestone 2.5.G5.M3 — Relationship Graph Readiness

Status: Completed (2026-08-25)
Goal: Track E — Schema Pre-Work
Phase: 2.5 — Provider Generalization & Foundation
Estimated effort: 1 day
ADR: ADR-0049

Why This Milestone Exists

Phase 3's extraction / conflict pipeline will write typed relationship edges at volume, and Phase 5 will walk supersession chains with recursive CTEs. Landing an org-safe table plus graph-traversal indexes now avoids a schema and performance cliff when those writers start.

Non-Goals

Application code using the new index or view (pure schema-readiness)
Changing the relationship type taxonomy
Adding new edge types
Apache AGE / external graph database

What shipped

Migration 000016_create_memory_relationships — greenfield CREATE (not index-only ALTER)
Dual composite FKs (source|target_memory_id, org_id) → memories; self-loop + confidence CHECKs
Indexes (org_id, source_memory_id, relationship_type) and (org_id, target_memory_id, relationship_type)
View memory_supersession_edges (security_invoker) + resolve_supersession_tip (depth/org/cycle)
FORCE RLS via rls_org_visible; integration tests; ADR-0049; 3.1.1 expand-not-CREATE note

Success signals

Migration applies cleanly; no application writers depend on the new objects
EXPLAIN on sample source/target+type filters mentions the traversal indexes
make db-migrate / migrate smoke to version 16
Forward-only expand-contract consistent with ADR-0005
DATABASE_SCHEMA.md updated

Prerequisites

Milestone 2.5.G5.M1 (temporal validity columns)
Milestone 2.5.G5.M2 (multi-label category support)

Orientation (historical sketch)

SQL

-- Sketch only — shipped path is CREATE + dual org-scoped indexes (000016 / ADR-0049)
CREATE INDEX idx_memory_relationships_source_type
 ON ibex_core.memory_relationships(source_memory_id, relationship_type);