code re-org and bugfix hanging hourly snapshot

db/helpers.go

@@ -135,12 +135,22 @@ func TableHasRows(ctx context.Context, dbConn *sqlx.DB, table string) (bool, err
 	if err := ValidateTableName(table); err != nil {
 		return false, err
 	}
+	// Avoid hanging on locked tables; apply a short timeout.
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	var cancel context.CancelFunc
+	ctx, cancel = context.WithTimeout(ctx, 15*time.Second)
+	defer cancel()
 	query := fmt.Sprintf(`SELECT 1 FROM %s LIMIT 1`, table)
 	var exists int
 	if err := getLog(ctx, dbConn, &exists, query); err != nil {
 		if err == sql.ErrNoRows {
 			return false, nil
 		}
+		if errors.Is(err, context.DeadlineExceeded) || errors.Is(err, context.Canceled) {
+			return false, nil
+		}
 		return false, err
 	}
 	return true, nil