Question

我正在执行一个query_string查询，其中包含多个字段_all和tags.name上的一个字词，并尝试了解评分。查询：{"query":{"query_string":{"query":"animal","fields":["_all","tags.name"]}}}。以下是查询返回的文档：

文档1 与tags.name完全匹配，但不在_all上。
8号文档与tags.name和_all完全匹配。

文件8应该获胜，而且确实如此，但我对得分如何运作感到困惑。似乎文档1因其tags.name分数乘以IDF两次而受到惩罚，而文档8的tags.name分数仅乘以IDF一次。简而言之：

他们都有一个组件weight(tags.name:animal in 0) [PerFieldSimilarity]。
在文档1中，我们有weight = score = queryWeight x fieldWeight。
在文档8中，我们有weight = fieldWeight！

由于queryWeight包含idf，因此会导致文档1被其idf两次处罚。

有人能理解这个吗？

其他信息

如果我从查询字段中删除_all，则queryWeight完全不在解释中。
添加"use_dis_max":true作为选项无效。
- 但是，另外添加"tie_breaker":0.7（或任何值）会影响文档8，方法是为文档1提供更复杂的公式。
- 思考：布尔查询（这是）可能会故意这样做，以便为匹配多个子查询的查询提供更多权重，这似乎是合理的。但是，这对于dis_max查询没有任何意义，因为它只能返回子查询的最大值。

以下是相关的解释请求。寻找嵌入式评论。

文档1 （仅在tags.name上匹配）：

curl -XGET 'http://localhost:9200/questions/question/1/_explain?pretty' -d '{"query":{"query_string":{"query":"animal","fields":["_all","tags.name"]}}}'：

{
  "ok" : true,
  "_index" : "questions_1390104463",
  "_type" : "question",
  "_id" : "1",
  "matched" : true,
  "explanation" : {
    "value" : 0.058849156,
    "description" : "max of:",
    "details" : [ {
      "value" : 0.058849156,
      "description" : "weight(tags.name:animal in 0) [PerFieldSimilarity], result of:",
      // weight = score = queryWeight x fieldWeight
      "details" : [ {
        // score and queryWeight are NOT a part of the other explain!
        "value" : 0.058849156,
        "description" : "score(doc=0,freq=1.0 = termFreq=1.0\n), product of:",
        "details" : [ {
          "value" : 0.30685282,
          "description" : "queryWeight, product of:",
          "details" : [ {
            // This idf is NOT a part of the other explain!
            "value" : 0.30685282,
            "description" : "idf(docFreq=1, maxDocs=1)"
          }, {
            "value" : 1.0,
            "description" : "queryNorm"
          } ]
        }, {
          "value" : 0.19178301,
          "description" : "fieldWeight in 0, product of:",
          "details" : [ {
            "value" : 1.0,
            "description" : "tf(freq=1.0), with freq of:",
            "details" : [ {
              "value" : 1.0,
              "description" : "termFreq=1.0"
            } ]
          }, {
            "value" : 0.30685282,
            "description" : "idf(docFreq=1, maxDocs=1)"
          }, {
            "value" : 0.625,
            "description" : "fieldNorm(doc=0)"
          } ]
        } ]
      } ]
    } ]
  }

8号文档（_all和tags.name匹配）：

curl -XGET 'http://localhost:9200/questions/question/8/_explain?pretty' -d '{"query":{"query_string":{"query":"animal","fields":["_all","tags.name"]}}}'：

{
  "ok" : true,
  "_index" : "questions_1390104463",
  "_type" : "question",
  "_id" : "8",
  "matched" : true,
  "explanation" : {
    "value" : 0.15342641,
    "description" : "max of:",
    "details" : [ {
      "value" : 0.033902764,
      "description" : "btq, product of:",
      "details" : [ {
        "value" : 0.033902764,
        "description" : "weight(_all:anim in 0) [PerFieldSimilarity], result of:",
        "details" : [ {
          "value" : 0.033902764,
          "description" : "fieldWeight in 0, product of:",
          "details" : [ {
            "value" : 0.70710677,
            "description" : "tf(freq=0.5), with freq of:",
            "details" : [ {
              "value" : 0.5,
              "description" : "phraseFreq=0.5"
            } ]
          }, {
            "value" : 0.30685282,
            "description" : "idf(docFreq=1, maxDocs=1)"
          }, {
            "value" : 0.15625,
            "description" : "fieldNorm(doc=0)"
          } ]
        } ]
      }, {
        "value" : 1.0,
        "description" : "allPayload(...)"
      } ]
    }, {
      "value" : 0.15342641,
      "description" : "weight(tags.name:animal in 0) [PerFieldSimilarity], result of:",
      // weight = fieldWeight
      // No score or queryWeight in sight!
      "details" : [ {
        "value" : 0.15342641,
        "description" : "fieldWeight in 0, product of:",
        "details" : [ {
          "value" : 1.0,
          "description" : "tf(freq=1.0), with freq of:",
          "details" : [ {
            "value" : 1.0,
            "description" : "termFreq=1.0"
          } ]
        }, {
          "value" : 0.30685282,
          "description" : "idf(docFreq=1, maxDocs=1)"
        }, {
          "value" : 0.5,
          "description" : "fieldNorm(doc=0)"
        } ]
      } ]
    } ]
  }
}

Answer 1

我没有回答。只想提一下我向Elasticsearch论坛发帖的问题：https://groups.google.com/forum/#!topic/elasticsearch/xBKlFkq0SP0 当我得到答案时，我会在这里通知。

为什么queryWeight包含在同一查询中的某些结果分数，而不包括其他结果分数？

1 个答案: