private void assignStringNoNullsRepeating(int index, int size,
      BytesColumnVector columnVector) {
    for(int i = 0; i < size; ++i) {
      vectorHashKeyWrappers[i].assignString(
          index,
          columnVector.vector[0],
          columnVector.start[0],
          columnVector.length[0]);
    }
  }
Helper method to assign values from a vector column into the key wrapper.
Optimized for double type, no nulls, repeat values, no selection vector.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/wrapper/VectorHashKeyWrapperBatch.java