5.Elasticsearch 如何手动控制全文检索结果的精准度

最新推荐文章于 2025-06-08 12:12:10 发布

翻译最新推荐文章于 2025-06-08 12:12:10 发布 · 209 阅读

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本文探讨了在Elasticsearch中使用Java、Hadoop、Spark和相关技术进行全文检索的方法，包括多值检索、精确匹配控制及关键词组合搜索。

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全文检索的时候，进行多个值的检索，有两种做法，match query；should
控制搜索结果精准度：and operator，minimum_should_match

 
POST /forum/article/_bulk
{ "index": { "_id": 1 }}
{ "articleID" : "XHDK-A-1293-#fJ3", "userID" : 1, "hidden": false, "postDate": "2017-01-01" }
{ "index": { "_id": 2 }}
{ "articleID" : "KDKE-B-9947-#kL5", "userID" : 1, "hidden": false, "postDate": "2017-01-02" }
{ "index": { "_id": 3 }}
{ "articleID" : "JODL-X-1937-#pV7", "userID" : 2, "hidden": false, "postDate": "2017-01-01" }
{ "index": { "_id": 4 }}
{ "articleID" : "QQPX-R-3956-#aD8", "userID" : 2, "hidden": true, "postDate": "2017-01-02" }

POST /forum/article/_bulk
{ "update": { "_id": "1"} }
{ "doc" : {"title" : "this is java and elasticsearch blog"} }
{ "update": { "_id": "2"} }
{ "doc" : {"title" : "this is java blog"} }
{ "update": { "_id": "3"} }
{ "doc" : {"title" : "this is elasticsearch blog"} }
{ "update": { "_id": "4"} }
{ "doc" : {"title" : "this is java, elasticsearch, hadoop blog"} }
{ "update": { "_id": "5"} }
{ "doc" : {"title" : "this is spark blog"} }

1.搜索标题中包含java或elasticsearch的blog

这个，就跟之前的那个term query，不一样了。不是搜索exact value，是进行full text全文检索。
match query，是负责进行全文检索的。当然，如果要检索的field，是not_analyzed类型的，那么match query也相当于term query。

GET /forum/article/_search
{
    "query": {
        "match": {
            "title": "java elasticsearch"
        }
    }
}

结果：
{
  "took" : 7,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 4,
    "max_score" : 0.8092568,
    "hits" : [
      {
        "_index" : "forum",
        "_type" : "article",
        "_id" : "4",
        "_score" : 0.8092568,
        "_source" : {
          "articleID" : "QQPX-R-3956-#aD8",
          "userID" : 2,
          "hidden" : true,
          "postDate" : "2017-01-02",
          "title" : "this is java, elasticsearch, hadoop blog"
        }
      },
      {
        "_index" : "forum",
        "_type" : "article",
        "_id" : "1",
        "_score" : 0.5753642,
        "_source" : {
          "articleID" : "XHDK-A-1293-#fJ3",
          "userID" : 1,
          "hidden" : false,
          "postDate" : "2017-01-01",
          "title" : "this is java and elasticsearch blog"
        }
      },
      {
        "_index" : "forum",
        "_type" : "article",
        "_id" : "3",
        "_score" : 0.2876821,
        "_source" : {
          "articleID" : "JODL-X-1937-#pV7",
          "userID" : 2,
          "hidden" : false,
          "postDate" : "2017-01-01",
          "title" : "this is elasticsearch blog"
        }
      },
      {
        "_index" : "forum",
        "_type" : "article",
        "_id" : "2",
        "_score" : 0.19856805,
        "_source" : {
          "articleID" : "KDKE-B-9947-#kL5",
          "userID" : 1,
          "hidden" : false,
          "postDate" : "2017-01-02",
          "title" : "this is java blog"
        }
      }
    ]
  }
}

2、搜索标题中包含java和elasticsearch的blog

搜索结果精准控制的第一步：灵活使用and关键字，如果你是希望所有的搜索关键字都要匹配的，那么就用and，可以实现单纯match query无法实现的效果

GET /forum/article/_search
{
    "query": {
        "match": {
            "title": {
		"query": "java elasticsearch",
		"operator": "and"
   	    }
        }
    }
}

结果：
{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 2,
    "max_score" : 0.8092568,
    "hits" : [
      {
        "_index" : "forum",
        "_type" : "article",
        "_id" : "4",
        "_score" : 0.8092568,
        "_source" : {
          "articleID" : "QQPX-R-3956-#aD8",
          "userID" : 2,
          "hidden" : true,
          "postDate" : "2017-01-02",
          "title" : "this is java, elasticsearch, hadoop blog"
        }
      },
      {
        "_index" : "forum",
        "_type" : "article",
        "_id" : "1",
        "_score" : 0.5753642,
        "_source" : {
          "articleID" : "XHDK-A-1293-#fJ3",
          "userID" : 1,
          "hidden" : false,
          "postDate" : "2017-01-01",
          "title" : "this is java and elasticsearch blog"
        }
      }
    ]
  }
}

3、搜索包含java，elasticsearch，spark，hadoop，4个关键字中，至少3个的blog

控制搜索结果的精准度的第二步：指定一些关键字中，必须至少匹配其中的多少个关键字，才能作为结果返回

GET /forum/article/_search
{
  "query": {
    "match": {
      "title": {
        "query": "java elasticsearch spark hadoop",
        "minimum_should_match": "75%"
      }
    }
  }
}

结果

{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 1,
    "max_score" : 1.449981,
    "hits" : [
      {
        "_index" : "forum",
        "_type" : "article",
        "_id" : "4",
        "_score" : 1.449981,
        "_source" : {
          "articleID" : "QQPX-R-3956-#aD8",
          "userID" : 2,
          "hidden" : true,
          "postDate" : "2017-01-02",
          "title" : "this is java, elasticsearch, hadoop blog"
        }
      }
    ]
  }
}

4、用bool组合多个搜索条件，来搜索title

GET /forum/article/_search
{
  "query": {
    "bool": {
      "must":     { "match": { "title": "java" }},
      "must_not": { "match": { "title": "spark"  }},
      "should": [
                  { "match": { "title": "hadoop" }},
                  { "match": { "title": "elasticsearch"   }}
      ]
    }
  }
}

bool组合多个搜索条件，如何计算relevance score

must和should搜索对应的分数，加起来，除以must和should的总数

排名第一：java，同时包含should中所有的关键字，hadoop，elasticsearch
排名第二：java，同时包含should中的elasticsearch
排名第三：java，不包含should中的任何关键字

should是可以影响相关度分数的

must是确保说，谁必须有这个关键字，同时会根据这个must的条件去计算出document对这个搜索条件的relevance score
在满足must的基础之上，should中的条件，不匹配也可以，但是如果匹配的更多，那么document的relevance score就会更高

{
  "took" : 2,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 3,
    "max_score" : 1.449981,
    "hits" : [
      {
        "_index" : "forum",
        "_type" : "article",
        "_id" : "4",
        "_score" : 1.449981,
        "_source" : {
          "articleID" : "QQPX-R-3956-#aD8",
          "userID" : 2,
          "hidden" : true,
          "postDate" : "2017-01-02",
          "title" : "this is java, elasticsearch, hadoop blog"
        }
      },
      {
        "_index" : "forum",
        "_type" : "article",
        "_id" : "1",
        "_score" : 0.5753642,
        "_source" : {
          "articleID" : "XHDK-A-1293-#fJ3",
          "userID" : 1,
          "hidden" : false,
          "postDate" : "2017-01-01",
          "title" : "this is java and elasticsearch blog"
        }
      },
      {
        "_index" : "forum",
        "_type" : "article",
        "_id" : "2",
        "_score" : 0.19856805,
        "_source" : {
          "articleID" : "KDKE-B-9947-#kL5",
          "userID" : 1,
          "hidden" : false,
          "postDate" : "2017-01-02",
          "title" : "this is java blog"
        }
      }
    ]
  }
}

5.搜索java，hadoop，spark，elasticsearch，至少包含其中3个关键字

默认情况下，should是可以不匹配任何一个的，比如上面的搜索中，this is java blog，就不匹配任何一个should条件
但是有个例外的情况，如果没有must的话，那么should中必须至少匹配一个才可以
比如下面的搜索，should中有4个条件，默认情况下，只要满足其中一个条件，就可以匹配作为结果返回

但是可以精准控制，should的4个条件中，至少匹配几个才能作为结果返回

GET /forum/article/_search
{
  "query": {
    "bool": {
      "should": [
        { "match": { "title": "java" }},
        { "match": { "title": "elasticsearch"   }},
        { "match": { "title": "hadoop"   }},
    { "match": { "title": "spark"   }}
      ],
      "minimum_should_match": 3 
    }
  }
}