@Override
    protected Project recreateTopOperator(RelBuilder builder, RexBuilder rexBuilder,
        int[] adjustments, Project topProject, RelNode newInputOperator) {
      return (Project) recreateProjectOperator(builder, rexBuilder, adjustments,
          topProject, newInputOperator, true);
    }
SemiJoinRule that matches a Project on top of a Join with an Aggregate
as its right child.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveSemiJoinRule.java