elasticsearch学习笔记高级篇六在案例中如果通过手动控制全文检索结果的精准度

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准备数据：

POST /forum/_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"}

1、为帖子数据增加标题字段

POST /forum/_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"} }

2、搜索标题中包含 java 或 elasticsearch 的 blog

这个就跟之前的那个 term filter/query 不一样了。不是搜索 exact value，而是进行 full text 全文搜索。
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/_search
{
  "query": {
    "match": {"title": "java elasticsearch"}
  }
}
{
  "took" : 1139,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 4,
      "relation" : "eq"
    },
    "max_score" : 0.97797304,
    "hits" : [
      {
        "_index" : "forum",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 0.97797304,
        "_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"
        }
      },
      {
        "_index" : "forum",
        "_type" : "_doc",
        "_id" : "4",
        "_score" : 0.97797304,
        "_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"
        }
      },
      {
        "_index" : "forum",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 0.57843524,
        "_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"
        }
      },
      {
        "_index" : "forum",
        "_type" : "_doc",
        "_id" : "3",
        "_score" : 0.57843524,
        "_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"
        }
      }
    ]
  }
}

3、搜索标题中包含 java 和 elasticsearch 的 blog

搜索结果精确控制的第一步就是灵活使用 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/_search
{
  "query": {
    "match": {
      "title": {
        "query": "java elasticsearch",
        "operator": "and"
      }
    }
  }
}
{
  "took" : 6,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : 0.97797304,
    "hits" : [
      {
        "_index" : "forum",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 0.97797304,
        "_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"
        }
      },
      {
        "_index" : "forum",
        "_type" : "_doc",
        "_id" : "4",
        "_score" : 0.97797304,
        "_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"
        }
      }
    ]
  }
}

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

控制搜索结果的精确度的第二步就是指定一些关键字中，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/_search
{
  "query": {
    "match": {
      "title": {
        "query": "java elasticsearch spark hadoop",
        "minimum_should_match": 3
      }
    }
  }
}
{
  "took" : 4,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 2.2356422,
    "hits" : [
      {
        "_index" : "forum",
        "_type" : "_doc",
        "_id" : "4",
        "_score" : 2.2356422,
        "_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"
        }
      }
    ]
  }
}

5、用 bool 组合多个搜索条件，来搜索 title

GET /forum/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {"title": "java"}
        }
      ],
      "must_not": [
        {
          "match": {"title": "spark"}
        }
      ],
      "should": [
        {
          "match": {"title": "hadoop"}
        },
        {
          "match": {"title": "elasticsearch"}
        }
      ]
    }
  }
}
{
  "took" : 12,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 3,
      "relation" : "eq"
    },
    "max_score" : 2.2356422,
    "hits" : [
      {
        "_index" : "forum",
        "_type" : "_doc",
        "_id" : "4",
        "_score" : 2.2356422,
        "_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"
        }
      },
      {
        "_index" : "forum",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 0.97797304,
        "_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"
        }
      },
      {
        "_index" : "forum",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 0.57843524,
        "_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"
        }
      }
    ]
  }
}

6、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 的总分数
所以排在第一位的是：包含 java、hadoop、elasticsearch
排在第二位的是：包含 java、elasticsearch
排在第三位的是：包含 java

should 是可以影响相关度分数的

must 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 的基础上，should 中的条件，不匹配也是可以的，但是如果匹配的更多，那么 document 的 relevance score 就会更高。

7、should 实现搜索四个关键字中至少包含三个关键字

默认情况下，should 是可以不匹配任何一个的，但是有一个例外的情况，就是如果没有 must 的情况下，那么 should 中必须至少匹配一个才可以

GET /forum/_search
{
  "query": {
    "bool": {
      "should": [
        {
          "match": {"title": "java"}
        },
        {
          "match": {"title": "elasticsearch"}
        },
        {
          "match": {"title": "hadoop"}
        },
        {
          "match": {"title": "spark"}
        }
      ],
      "minimum_should_match": 3
    }
  }
}
{
  "took" : 2,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 2.2356422,
    "hits" : [
      {
        "_index" : "forum",
        "_type" : "_doc",
        "_id" : "4",
        "_score" : 2.2356422,
        "_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"
        }
      }
    ]
  }
}

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elasticsearch
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2019-06-01
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