@Override
  void run() throws Exception {

    for (Entry<String, LogicalOutput> outputEntry : outputs.entrySet()) {
      LOG.info("Starting Output: " + outputEntry.getKey());
      if (!isAborted()) {
        outputEntry.getValue().start();
        ((TezKVOutputCollector) outMap.get(outputEntry.getKey())).initialize();
      }
    }

    // run the operator pipeline
    startAbortChecks();
    while (sources[bigTablePosition].pushRecord()) {
      addRowAndMaybeCheckAbort();
    }
  }
Process input from tez LogicalInput and write output - for a map plan
Just pump the records through the query plan.
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/ReduceRecordProcessor.java