Elasticsearch完成字段与jdbc河

Question

我正在使用JDBC River加载数据：

curl -XPUT 'localhost:9200/_river/my_jdbc_river/_meta' -d '{
    "type": "jdbc",
        "jdbc": {
        "url": "jdbc:mysql://localhost:3306/test",
            "user": "root",
            "password": "root",
            "sql": "SELECT TAD.ID AS _id, TAD.APP_NAME AS appName FROM TOPIC_APP_DETAILS TAD ",
            "index": "app_index",
            "type": "app_type",
            "mappings": {
            "app_type": {
                "properties": {
                    "appName": {
                        "type": "completion"
                    }
                }
            }
        }
    }
}

当我执行以下查询时， ClassCastException [org.elasticsearch.index.mapper.core.StringFieldMapper无法强制转换为org.elasticsearch.index.mapper.core.CompletionFieldMapper] ;

curl -X POST 'localhost:9200/app_index/_suggest?pretty' -d '{
    "app-suggest" : {
        "text" : "cri",
            "completion" : {
            "field" : "appName"
        }
    }
}

请提出我在这里缺少的内容。