概述
继续跟中华石杉老师学习ES，第15篇
课程地址： https://www.roncoo.com/view/55
官网
https://www.elastic.co/guide/en/elasticsearch/reference/current/copy-to.html
例子
新增字段，用作测试
PUT /forum/_mapping/article { "properties": { "new_author_first_name": { "type": "text", "copy_to": "new_author_full_name" }, "new_author_last_name": { "type": "text", "copy_to": "new_author_full_name" }, "new_author_full_name": { "type": "text" } } }
更新数据
POST /forum/article/_bulk { "update": { "_id": "1"} } { "doc" : {"new_author_first_name" : "Peter", "new_author_last_name" : "Smith"} } { "update": { "_id": "2"} } { "doc" : {"new_author_first_name" : "Smith", "new_author_last_name" : "Williams"} } { "update": { "_id": "3"} } { "doc" : {"new_author_first_name" : "Jack", "new_author_last_name" : "Ma"} } { "update": { "_id": "4"} } { "doc" : {"new_author_first_name" : "Robbin", "new_author_last_name" : "Li"} } { "update": { "_id": "5"} } { "doc" : {"new_author_first_name" : "Tonny", "new_author_last_name" : "Peter Smith"} }
查询
GET /forum/article/_search { "query": { "match": { "new_author_full_name": "Peter Smith" } } }
返回结果
{ "took": 3, "timed_out": false, "_shards": { "total": 1, "successful": 1, "skipped": 0, "failed": 0 }, "hits": { "total": 2, "max_score": 2.3258216, "hits": [ { "_index": "forum", "_type": "article", "_id": "1", "_score": 2.3258216, "_source": { "articleID": "XHDK-A-1293-#fJ3", "userID": 1, "hidden": false, "postDate": "2017-01-01", "tag": [ "java", "hadoop" ], "tag_cnt": 2, "view_cnt": 30, "title": "this is java and elasticsearch blog", "content": "i like to write best elasticsearch article", "sub_title": "learning more courses", "author_first_name": "Peter", "author_last_name": "Smith", "new_author_last_name": "Smith", "new_author_first_name": "Peter" } }, { "_index": "forum", "_type": "article", "_id": "5", "_score": 1.7770995, "_source": { "articleID": "DHJK-B-1395-#Ky5", "userID": 3, "hidden": false, "postDate": "2019-05-01", "tag": [ "elasticsearch" ], "tag_cnt": 1, "view_cnt": 10, "title": "this is spark blog", "content": "spark is best big data solution based on scala ,an programming language similar to java", "sub_title": "haha, hello world", "author_first_name": "Tonny", "author_last_name": "Peter Smith", "new_author_last_name": "Peter Smith", "new_author_first_name": "Tonny" } } ] } }
总结
cross field的问题，是否解决了呢？
问题1：只是找到尽可能多的field匹配的doc，而不是某个field完全匹配的doc
答: 解决，最匹配的document被最先返回
问题2：most_fields，没办法用minimum_should_match去掉长尾数据，就是匹配的特别少的结果
答: 解决，可以使用minimum_should_match去掉长尾数据
问题3：TF/IDF算法，比如Peter Smith和Smith Williams，搜索Peter
Smith的时候，由于first_name中很少有Smith的，所以query在所有document中的频率很低，得到的分数很高，可能Smith Williams反而会排在Peter Smith前面
答: 解决，Smith和Peter在一个field了，所以在所有document中出现的次数是均匀的，不会有极端的偏差
