protected void setupVOutContext() {
    vOutContext.resetProjectionColumns();
    final int count = outputColumnNames.length;
    for (int i = 0; i < count; ++i) {
      String columnName = outputColumnNames[i];
      int outputColumn = outputProjectionColumnMap[i];
      vOutContext.addProjectionColumn(columnName, outputColumn);
    }
  }
Setup the vectorized row batch description of the output of the native vectorized PTF
operator.  Use the output projection we previously built from a mixture of input
columns and new scratch columns.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/ptf/VectorPTFOperator.java