@Override
  void run() throws Exception {
    KeyValueReader reader = mrInput.getReader();

    //process records until done
    while (reader.next()) {
      boolean needMore = processRow(reader.getCurrentKey(),
          reader.getCurrentValue());
      if (!needMore || isAborted()) {
        break;
      }
    }
  }
Record processor for fast merging of files.
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/MergeFileRecordProcessor.java