public boolean enablePushDownUseTemplate() {
      return enablePushDownUseTemplate;
    }
ProjectNode is used to project the output columns of the child node.

<p>There are two cases where ProjectNode is used:
<li>Because of the removal of the FilterNode (FilterAndProjectOperator), we need a
    ProjectNode to do the projection.
<li>For ALIGN_BY_DEVICE query, the ProjectNode is used to ensure the order of the output
    columns is consistent with before optimization (required by TreeMergeSortOperator).
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/optimization/PredicatePushDown.java