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