synchronized public static HiveOnTezCostModel getCostModel(HiveConf conf) {
    if (INSTANCE == null) {
      INSTANCE = new HiveOnTezCostModel(conf);
    }

    return INSTANCE;
  }
Cost model for Tez execution engine.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/cost/HiveOnTezCostModel.java