@Override
  public String vectorExpressionParameters() {
    return "val " + displayUtf8Bytes(value) + ", " + getColumnParamString(1, inputColumnNum[0]);
  }
Vectorized instruction to concatenate a scalar to a string column and put
the result in an output column.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/StringScalarConcatStringGroupCol.java