public boolean isNeeded() {
      switch (this) {
        case NO:
        case NULL:
        case NO_NULL:
          return false;
        default:
          return true;
      }
    }
Does the RecordReader need to include this set of records?
@return true unless none of the rows qualify
storage-api/src/java/org/apache/hadoop/hive/ql/io/sarg/SearchArgument.java