09深度探秘搜索技术_基于boost的细粒度搜索条件权重控制

需求：搜索标题中包含blog的帖子，同时呢，如果标题中包含hadoop或elasticsearch或java 或spark ，包含spark的帖子优先搜索出来

知识点，搜索条件的权重，boost，可以将某个搜索条件的权重加大，此时当匹配这个搜索条件和匹配另一个搜索条件的document，计算relevance score时，匹配权重更大的搜索条件的document，relevance score会更高，当然也就会优先被返回回来

默认情况下，搜索条件的权重都是一样的，都是1

GET /forum/article/_search 
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "title": "blog"
          }
        }
      ],
      "should": [
        {
          "match": {
            "title": {
              "query": "java"
            }
          }
        },
        {
          "match": {
            "title": {
              "query": "hadoop"
            }
          }
        },
        {
          "match": {
            "title": {
              "query": "elasticsearch"
            }
          }
        },
        {
          "match": {
            "title": {
              "query": "spark",
              "boost": 5
            }
          }
        }
      ]
    }
  }
}

响应结果

{
  "took": 26,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 5,
    "max_score": 1.7260925,
    "hits": [
      {
        "_index": "forum",
        "_type": "article",
        "_id": "5",
        "_score": 1.7260925,
        "_source": {
          "articleID": "DHJK-B-1395-#Ky5",
          "userID": 3,
          "hidden": false,
          "postDate": "2021-11-11",
          "tag": [
            "elasticsearch"
          ],
          "tag_cnt": 1,
          "view_cnt": 10,
          "title": "this is spark blog"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "4",
        "_score": 1.4930474,
        "_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": "article",
        "_id": "1",
        "_score": 0.80226827,
        "_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": "article",
        "_id": "3",
        "_score": 0.5753642,
        "_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"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "2",
        "_score": 0.3971361,
        "_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"
        }
      }
    ]
  }
}