@Override
  public void close() throws Exception {
    for (Operator child : children) {
      if (child != null) {
        child.close();
      }
    }
    // friendly for gc
    inputTsBlocks = null;
  }
@param currentChildIndex the index of the child
@throws Exception Potential Exception thrown by Operator.close()
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/process/AbstractConsumeAllOperator.java