@Override
  public int hashCode() {
    return Objects.hash(Bytes.hashCode(getFamily()), Bytes.hashCode(getQualifier()), this.op,
      getComparator(), getFilterIfMissing(), getLatestVersionOnly());
  }
The only CF this filter needs is given column family. So, it's the only essential column in
whole scan. If filterIfMissing == false, all families are essential, because of possibility of
skipping the rows without any data in filtered CF.
hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueFilter.java