白话Elasticsearch25-深度探秘搜索技术之四种常见的相关度分数优化方法

2021-08-17 14:50:52 浏览数 (1)

概述

继续跟中华石杉老师学习ES,第25篇

课程地址: https://www.roncoo.com/view/55


query-time boost

query-time boost 不多说了 权重 ,直接上例子吧

代码语言:javascript复制
GET /forum/article/_search
{
  "query": {
    "bool": {
      "should": [
        {
          "match": {
            "title": {
              "query": "java spark",
              "boost": 2
            }
          }
        },
        {
          "match": {
            "content": "java spark"
          }
        }
      ]
    }
  }
}

返回数据:

代码语言:javascript复制
{
  "took": 71,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 4,
    "max_score": 4.0036817,
    "hits": [
      {
        "_index": "forum",
        "_type": "article",
        "_id": "5",
        "_score": 4.0036817,
        "_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 spark",
          "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"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "2",
        "_score": 2.2444534,
        "_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",
          "sub_title": "learned a lot of course",
          "author_first_name": "Smith",
          "author_last_name": "Williams",
          "new_author_last_name": "Williams",
          "new_author_first_name": "Smith"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "1",
        "_score": 1.241217,
        "_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": "4",
        "_score": 1.241217,
        "_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",
          "sub_title": "both of them are good",
          "author_first_name": "Robbin",
          "author_last_name": "Li",
          "new_author_last_name": "Li",
          "new_author_first_name": "Robbin"
        }
      }
    ]
  }
}

比对下 不加 boost的得分情况


negative boost

先看看之前的写法

代码语言:javascript复制
GET /forum/article/_search 
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "content": "java"
          }
        }
      ],
      "must_not": [
        {
          "match": {
            "content": "spark"
          }
        }
      ]
    }
  }
}

返回

上面的DSL

  • 搜索包含java,不包含spark的doc,但是这样子很死板
  • 搜索包含java,尽量不包含spark的doc,如果包含了spark,不会说排除掉这个doc,而是说将这个doc的分数降低
  • 包含了negative term的doc,分数乘以negative boost,分数降低

改造下

代码语言:javascript复制
GET /forum/article/_search 
{
  "query": {
    "boosting": {
      "positive": {
        "match": {
          "content": "java"
        }
      },
      "negative": {
        "match": {
          "content": "spark"
        }
      },
      "negative_boost": 0.2
    }
  }
}

返回:

代码语言:javascript复制
{
  "took": 5,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 2,
    "max_score": 0.7721133,
    "hits": [
      {
        "_index": "forum",
        "_type": "article",
        "_id": "2",
        "_score": 0.7721133,
        "_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",
          "sub_title": "learned a lot of course",
          "author_first_name": "Smith",
          "author_last_name": "Williams",
          "new_author_last_name": "Williams",
          "new_author_first_name": "Smith"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "5",
        "_score": 0.11508858,
        "_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 spark",
          "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"
        }
      }
    ]
  }
}

negative的doc,会乘以negative_boost,降低分数


constant_score

如果你压根儿不需要相关度评分,直接走constant_score加filter,所有的doc分数都是1,没有评分的概念了

代码语言:javascript复制
GET /forum/article/_search
{
  "query": {
    "constant_score": {
      "filter": {
        "bool": {
          "should": [
            {
              "term": {
                "title": "java"
              }
            },
            {
              "term": {
                "title": "spark"
              }
            }
          ]
        }
      }
    }
  }
}

返回

代码语言:javascript复制
{
  "took": 28,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 4,
    "max_score": 1,
    "hits": [
      {
        "_index": "forum",
        "_type": "article",
        "_id": "1",
        "_score": 1,
        "_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": "2",
        "_score": 1,
        "_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",
          "sub_title": "learned a lot of course",
          "author_first_name": "Smith",
          "author_last_name": "Williams",
          "new_author_last_name": "Williams",
          "new_author_first_name": "Smith"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "4",
        "_score": 1,
        "_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",
          "sub_title": "both of them are good",
          "author_first_name": "Robbin",
          "author_last_name": "Li",
          "new_author_last_name": "Li",
          "new_author_first_name": "Robbin"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "5",
        "_score": 1,
        "_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 spark",
          "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"
        }
      }
    ]
  }
}

_score都是1


重构查询结构

重构查询结果,在es新版本中,影响越来越小了。一般情况下,没什么必要的话,不用也行

代码语言:javascript复制
GET /forum/article/_search 
{
  "query": {
    "bool": {
      "should": [
        {
          "match": {
            "content": "java"
          }
        },
        {
          "match": {
            "content": "spark"
          }
        },
        {
          "bool": {
            "should": [
              {
                "match": {
                  "content": "solution"
                }
              },
              {
                "match": {
                  "content": "beginner"
                }
              }
            ]
          }
        }
      ]
    }
  }
}

返回

代码语言:javascript复制
{
  "took": 4,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 4,
    "max_score": 2.392071,
    "hits": [
      {
        "_index": "forum",
        "_type": "article",
        "_id": "5",
        "_score": 2.392071,
        "_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 spark",
          "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"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "4",
        "_score": 1.6389564,
        "_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",
          "sub_title": "both of them are good",
          "author_first_name": "Robbin",
          "author_last_name": "Li",
          "new_author_last_name": "Li",
          "new_author_first_name": "Robbin"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "3",
        "_score": 1.2540693,
        "_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",
          "sub_title": "we have a lot of fun",
          "author_first_name": "Jack",
          "author_last_name": "Ma",
          "new_author_last_name": "Ma",
          "new_author_first_name": "Jack"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "2",
        "_score": 0.7721133,
        "_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",
          "sub_title": "learned a lot of course",
          "author_first_name": "Smith",
          "author_last_name": "Williams",
          "new_author_last_name": "Williams",
          "new_author_first_name": "Smith"
        }
      }
    ]
  }
}

6.4.1的版本 已经没有作用了

代码语言:javascript复制
GET /forum/article/_search
{
  "query": {
    "bool": {
      "should": [
        {
          "match": {
            "content": "java"
          }
        },
        {
          "match": {
            "content": "spark"
          }
        },
        {
          "match": {
            "content": "solution"
          }
        },
        {
          "match": {
            "content": "beginner"
          }
        }
      ]
    }
  }
}

返回

代码语言:javascript复制
{
  "took": 4,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 4,
    "max_score": 2.392071,
    "hits": [
      {
        "_index": "forum",
        "_type": "article",
        "_id": "5",
        "_score": 2.392071,
        "_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 spark",
          "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"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "4",
        "_score": 1.6389564,
        "_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",
          "sub_title": "both of them are good",
          "author_first_name": "Robbin",
          "author_last_name": "Li",
          "new_author_last_name": "Li",
          "new_author_first_name": "Robbin"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "3",
        "_score": 1.2540693,
        "_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",
          "sub_title": "we have a lot of fun",
          "author_first_name": "Jack",
          "author_last_name": "Ma",
          "new_author_last_name": "Ma",
          "new_author_first_name": "Jack"
        }
      },
      {
        "_index": "forum",
        "_type": "article",
        "_id": "2",
        "_score": 0.7721133,
        "_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",
          "sub_title": "learned a lot of course",
          "author_first_name": "Smith",
          "author_last_name": "Williams",
          "new_author_last_name": "Williams",
          "new_author_first_name": "Smith"
        }
      }
    ]
  }
}

上面两个DSL 返回结果相同,得分也是相同的 。

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