Type Field Mapping - gnuhub/elasticsearch GitHub Wiki

Each document indexed is associated with an id and a type. The type, when indexing, is automatically indexed into an _type field. By default, the _type field is indexed (but not analyzed) and not stored. This means that the _type field can be used to query against it.

The _type field allows to store it as well, for example:

{
    "tweet" : {
        "_type" : {"store" : "yes"}
    }
}