public void flushRecursive() throws HiveException {
    flush();
    if (CollectionUtils.isNotEmpty(childOperators)) {
      for (Operator<?> child : childOperators) {
        child.flushRecursive();
      }
    }
  }
Process the row.

@param row
         The object representing the row.
@param tag
         The tag of the row usually means which parent this row comes from.
         Rows with the same tag should have exactly the same rowInspector
         all the time.
ql/src/java/org/apache/hadoop/hive/ql/exec/Operator.java