public @Nullable FemLocalIndex findSemiJoinIndexByCost(RelNode dimRel,
        List<Integer> actualLeftKeys, List<Integer> rightKeys,
        List<Integer> bestKeyOrder) {
      return null;
    }
Dummy class to allow code to compile.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveLoptSemiJoinOptimizer.java