when creating mapping and setting a fields index to not_analysed, FieldIndexOption.NotAnalyzed sets the mapping of the field in elastic search as analysed. I do understand from here https://www.elastic.co/guide/en/elasticsearch/guide/current/mapping-intro.html that "The other simple types (such as long, double, date etc) also accept the index parameter, but the only relevant values are no and not_analyzed, as their values are never analyzed."