Can someone explain me, how I should write mapping creating my new index. For creating _timestamp field in _source. I've checked https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-timestamp-field.html#_path_3 and still can't see _timestamp field in the _source.
It's out of the _source ,just like _index.You can query the _timestamp field,but in default it's not display in hits.