@Override
  public void closeOp(boolean aborted) throws HiveException {
    super.closeOp(aborted);

    // NOTE: The closeOp call on super MapJoinOperator can trigger Hybrid Grace additional
    // NOTE: processing and also FULL OUTER MapJoin non-match Small Table result generation. So,
    // NOTE: we flush the overflowBatch after the call.
    //
    if (!aborted && overflowBatch.size > 0) {
      forwardOverflow();
    }
    if (LOG.isDebugEnabled()) {
      LOG.debug("VectorMapJoinInnerLongOperator closeOp " + batchCounter + " batches processed");
    }
  }
On close, make sure a partially filled overflow batch gets forwarded.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/mapjoin/VectorMapJoinGenerateResultOperator.java