@Override
  protected void serializeAttributes(final DataOutputStream stream) throws IOException {
    PlanNodeType.ALTER_LOGICAL_VIEW.serialize(stream);
    // serialize other member variables for this node
    ReadWriteIOUtils.write(this.viewPathToSourceMap.size(), stream);
    for (final Map.Entry<PartialPath, ViewExpression> entry : viewPathToSourceMap.entrySet()) {
      entry.getKey().serialize(stream);
      ViewExpression.serialize(entry.getValue(), stream);
    }
  }
A map from target path to source expression. Yht target path is the name of this logical view,
and the source expression is the data source of this view.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/plan/node/metadata/write/view/AlterLogicalViewNode.java