@Override
  public PlanNode clone() {
    return new AggregationNode(
        getPlanNodeId(),
        getAggregationDescriptorList(),
        getGroupByTimeParameter(),
        getGroupByParameter(),
        getGroupByExpression(),
        outputEndTime,
        getScanOrder());
  }
This node is used to aggregate required series from multiple sources. The source data will be
input as a TsBlock, it may be raw data or partial aggregation result. This node will output the
final series aggregated result represented by TsBlock.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/plan/node/process/AggregationNode.java