feat(background): mark the payload-type backfill done at once when no observation is untyped (#244)

db/sqlc/mock/querier.go

@@ -1330,6 +1330,21 @@ func (mr *MockQuerierMockRecorder) GetTransportScopes(ctx any) *gomock.Call {
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "GetTransportScopes", reflect.TypeOf((*MockQuerier)(nil).GetTransportScopes), ctx)
 }
 
+// HasUntypedObservations mocks base method.
+func (m *MockQuerier) HasUntypedObservations(ctx context.Context, maxID int64) (bool, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "HasUntypedObservations", ctx, maxID)
+	ret0, _ := ret[0].(bool)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// HasUntypedObservations indicates an expected call of HasUntypedObservations.
+func (mr *MockQuerierMockRecorder) HasUntypedObservations(ctx, maxID any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "HasUntypedObservations", reflect.TypeOf((*MockQuerier)(nil).HasUntypedObservations), ctx, maxID)
+}
+
 // InsertChannelMessage mocks base method.
 func (m *MockQuerier) InsertChannelMessage(ctx context.Context, arg db.InsertChannelMessageParams) (db.InsertChannelMessageRow, error) {
 	m.ctrl.T.Helper()

db/sqlc/querier.go

@@ -192,6 +192,9 @@ type Querier interface {
 	GetTopNodesProbe(ctx context.Context, arg GetTopNodesProbeParams) ([]GetTopNodesProbeRow, error)
 	GetTransportScopeByName(ctx context.Context, name string) (int32, error)
 	GetTransportScopes(ctx context.Context) ([]GetTransportScopesRow, error)
+	// Whether any observation up to @max_id lacks a payload type. A full scan, run at most once per
+	// process by the payload-type backfill.
+	HasUntypedObservations(ctx context.Context, maxID int64) (bool, error)
 	// ============================================================
 	// CHANNEL MESSAGES
 	// ============================================================

db/sqlc/queries.sql.go

@@ -2694,6 +2694,22 @@ func (q *Queries) GetTransportScopes(ctx context.Context) ([]GetTransportScopesR
 	return items, nil
 }
 
+const hasUntypedObservations = `-- name: HasUntypedObservations :one
+SELECT EXISTS (
+  SELECT 1 FROM packet_observations
+  WHERE payload_type IS NULL AND id <= $1::bigint
+) AS untyped
+`
+
+// Whether any observation up to @max_id lacks a payload type. A full scan, run at most once per
+// process by the payload-type backfill.
+func (q *Queries) HasUntypedObservations(ctx context.Context, maxID int64) (bool, error) {
+	row := q.db.QueryRow(ctx, hasUntypedObservations, maxID)
+	var untyped bool
+	err := row.Scan(&untyped)
+	return untyped, err
+}
+
 const insertChannelMessage = `-- name: InsertChannelMessage :one
 
 WITH inserted AS (