<T> OptiqPrepare.PrepareResult<T> parseQuery(
     String sql, OptiqPrepare.Context prepareContext, int maxRowCount) {
   OptiqPrepare.Dummy.push(prepareContext);
   try {
     final OptiqPrepare prepare = prepareFactory.apply();
     return prepare.prepareSql(prepareContext, sql, null, Object[].class, maxRowCount);
   } finally {
     OptiqPrepare.Dummy.pop(prepareContext);
   }
 }
 public OptiqPrepare.SparkHandler spark() {
   final boolean enable = config().spark();
   return OptiqPrepare.Dummy.getSparkHandler(enable);
 }