private void findNewBlank() {
    long newBlank = gen.nextLong();
    while(newBlank == blank || lookup(newBlank)) {
      newBlank = gen.nextLong();
    }

    // replace existing blanks with new blanks
    for(int i = 0; i != n; i++) {
      if (t1[i] == blank) {
        t1[i] = newBlank;
      }
      if (t2[i] == blank) {
        t2[i] = newBlank;
      }
    }
    blank = newBlank;
  }
Need to change current blank value to something else because it is in
the input data set.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/CuckooSetLong.java