private SubPlan createSubPlan(PlanNode root) {
      PlanFragment fragment = new PlanFragment(getNextFragmentId(), root);
      return new SubPlan(fragment);
    }
Return true if we need to use ShuffleSinkNode instead of IdentitySinkNode.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/distribution/DistributionPlanner.java