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