白话Elasticsearch12深度探秘搜索技术之基于multi_match+bestfields语法实现dis_max+tie_breaker

概述

继续跟中华石杉老师学习ES&＃xff0c;第十二篇

课程地址&＃xff1a; https://www.roncoo.com/view/55

官网

https://www.elastic.co/guide/en/elasticsearch/reference/7.2/query-dsl-multi-match-query.html

示例


GET /forum/article/_search
{
"query": {
"dis_max": {
"queries": [
{
"match": {
"title": {
"query": "java beginner",
"minimum_should_match": "50%",
"boost": 2
}
}
},
{
"match": {
"content": {
"query": "java beginner",
"minimum_should_match": "50%"
}
}
}
],
"tie_breaker": 0.3
}
}
}


可以简化为

GET /forum/article/_search
{
"query": {
"multi_match": {
"query": "java beginner",
"type": "best_fields",
"fields": [
"title^2",
"content"
],
"tie_breaker": 0.3,
"minimum_should_match": "50%"
}
}
}


minimum_should_match的主要用途 &＃xff1a; 去长尾&＃xff0c;long tail
长尾是什么呢&＃xff0c;举个例子&＃xff1a;假设你搜索5个关键词&＃xff0c;但是很多结果是只匹配1个关键词的&＃xff0c;其实跟你想要的结果相差甚远&＃xff0c;这些结果就是长尾

minimum_should_match&＃xff0c;控制搜索结果的精准度&＃xff0c;只有匹配一定数量的关键词的数据&＃xff0c;才能返回

返回结果

{
"took": 1,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": 5,
"max_score": 1.4387287,
"hits": [
{
"_index": "forum",
"_type": "article",
"_id": "2",
"_score": 1.4387287,
"_source": {
"articleID": "KDKE-B-9947-#kL5",
"userID": 1,
"hidden": false,
"postDate": "2017-01-02",
"tag": [
"java"
],
"tag_cnt": 1,
"view_cnt": 50,
"title": "this is java blog",
"content": "i think java is the best programming language"
}
},
{
"_index": "forum",
"_type": "article",
"_id": "4",
"_score": 1.2162449,
"_source": {
"articleID": "QQPX-R-3956-#aD8",
"userID": 2,
"hidden": true,
"postDate": "2017-01-02",
"tag": [
"java",
"elasticsearch"
],
"tag_cnt": 2,
"view_cnt": 80,
"title": "this is java, elasticsearch, hadoop blog",
"content": "elasticsearch and hadoop are all very good solution, i am a beginner"
}
},
{
"_index": "forum",
"_type": "article",
"_id": "3",
"_score": 1.0341108,
"_source": {
"articleID": "JODL-X-1937-#pV7",
"userID": 2,
"hidden": false,
"postDate": "2017-01-01",
"tag": [
"hadoop"
],
"tag_cnt": 1,
"view_cnt": 100,
"title": "this is elasticsearch blog",
"content": "i am only an elasticsearch beginner"
}
},
{
"_index": "forum",
"_type": "article",
"_id": "1",
"_score": 0.977973,
"_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"
}
},
{
"_index": "forum",
"_type": "article",
"_id": "5",
"_score": 0.7116974,
"_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"
}
}
]
}
}