{
    "properties" : {
        "event" : {
            "properties" : {
                "category" : {
                    "type" : "keyword"
                }
            }
        },
        "user_name" : {
            "type" : "keyword"
        },
        "user_domain" : {
            "type" : "keyword"
        },
        "user_name_alias": {
            "type": "alias",
            "path": "user_name"
        }
    }
}