feat(retention): age out unreferenced observers when enabled (#126)

db/sqlc/mock/querier.go

@@ -71,6 +71,21 @@ func (mr *MockQuerierMockRecorder) DeleteOldNodes(ctx, lastSeen any) *gomock.Cal
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "DeleteOldNodes", reflect.TypeOf((*MockQuerier)(nil).DeleteOldNodes), ctx, lastSeen)
 }
 
+// DeleteOldObservers mocks base method.
+func (m *MockQuerier) DeleteOldObservers(ctx context.Context, lastSeen pgtype.Timestamptz) ([]uuid.UUID, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "DeleteOldObservers", ctx, lastSeen)
+	ret0, _ := ret[0].([]uuid.UUID)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// DeleteOldObservers indicates an expected call of DeleteOldObservers.
+func (mr *MockQuerierMockRecorder) DeleteOldObservers(ctx, lastSeen any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "DeleteOldObservers", reflect.TypeOf((*MockQuerier)(nil).DeleteOldObservers), ctx, lastSeen)
+}
+
 // DeleteOldPackets mocks base method.
 func (m *MockQuerier) DeleteOldPackets(ctx context.Context, lastHeardAt pgtype.Timestamptz) error {
 	m.ctrl.T.Helper()

db/sqlc/querier.go

@@ -22,6 +22,9 @@ type Querier interface {
 	// dangling in old routes there, but ReconfirmTask already prunes stale/ambiguous routes
 	// periodically and will clean those up on its own schedule.
 	DeleteOldNodes(ctx context.Context, lastSeen pgtype.Timestamptz) error
+	// Opt-in age-out: preserve retained history and manually recorded ownership.
+	// Bound deletions per cleanup tick and skip observers being updated by ingest.
+	DeleteOldObservers(ctx context.Context, lastSeen pgtype.Timestamptz) ([]uuid.UUID, error)
 	// Deletes packets and their observations older than the given cutoff.
 	// packet_observations cascade-delete via FK.
 	DeleteOldPackets(ctx context.Context, lastHeardAt pgtype.Timestamptz) error

db/sqlc/queries.sql.go

@@ -40,6 +40,46 @@ func (q *Queries) DeleteOldNodes(ctx context.Context, lastSeen pgtype.Timestampt
 	return err
 }
 
+const deleteOldObservers = `-- name: DeleteOldObservers :many
+WITH expired AS (
+    SELECT o.id
+    FROM observers o
+    WHERE o.last_seen < $1
+      AND (o.last_status_at IS NULL OR o.last_status_at < $1)
+      AND NOT EXISTS (SELECT 1 FROM packet_observations po WHERE po.observer_id = o.id)
+      AND NOT EXISTS (SELECT 1 FROM observer_telemetry ot WHERE ot.observer_id = o.id)
+      AND NOT EXISTS (SELECT 1 FROM observer_owners oo WHERE oo.observer_id = o.id)
+    ORDER BY o.last_seen, o.id
+    LIMIT 1000
+    FOR UPDATE OF o SKIP LOCKED
+)
+DELETE FROM observers o USING expired e
+WHERE o.id = e.id
+RETURNING o.id
+`
+
+// Opt-in age-out: preserve retained history and manually recorded ownership.
+// Bound deletions per cleanup tick and skip observers being updated by ingest.
+func (q *Queries) DeleteOldObservers(ctx context.Context, lastSeen pgtype.Timestamptz) ([]uuid.UUID, error) {
+	rows, err := q.db.Query(ctx, deleteOldObservers, lastSeen)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []uuid.UUID{}
+	for rows.Next() {
+		var id uuid.UUID
+		if err := rows.Scan(&id); err != nil {
+			return nil, err
+		}
+		items = append(items, id)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
 const deleteOldPackets = `-- name: DeleteOldPackets :exec
 DELETE FROM packets WHERE last_heard_at < $1
 `