elasticsearch - Elasticsearch查询在多个字段上更倾向于完全匹配而不是部分匹配

Question

我正在对具有多个字段的文档进行免费文本搜索。当我执行搜索时，我希望在任何标签上都具有完美匹配的文档具有更高的评分。有什么办法可以从查询中做到这一点？

例如，文档有两个字段，分别称为label-a和label-b，当我执行以下多重匹配查询时:

{
  "query": {
    "bool": {
      "must": [
        {
          "multi_match": {
            "query": "apple",
            "type": "most_fields",
            "fields": [
              "label-a",
              "label-b"
            ]
          }
        }
      ]
    }
  }
}

我得到以下结果(仅相关部分):

"hits": [
  {
    "_index": "salad",
    "_type": "fruit",
    "_id": "4",
    "_score": 0.581694,
    "_source": {
      "label-a": "apple pie and pizza",
      "label-b": "pineapple with apple juice"
    }
  },
  {
    "_index": "salad",
    "_type": "fruit",
    "_id": "2",
    "_score": 0.1519148,
    "_source": {
      "label-a": "grape",
      "label-b": "apple"
    }
  },
  {
    "_index": "salad",
    "_type": "fruit",
    "_id": "1",
    "_score": 0.038978107,
    "_source": {
      "label-a": "apple apple apple apple apple apple apple apple apple apple apple apple",
      "label-b": "raspberry"
    }
  },
  {
    "_index": "salad",
    "_type": "fruit",
    "_id": "3",
    "_score": 0.02250402,
    "_source": {
      "label-a": "apple pie and pizza",
      "label-b": "raspberry"
    }
  }
]

我希望第二个文档(对于 grape具有值 label-a和对于 apple具有值 label-b的文档)在我搜索值苹果时得分最高，并且其中一个标签具有该确切值。无论确切的术语出现在哪个标签上，它都应该起作用。

Answer 1

因为Elasticsearch使用tf / idf模型进行评分，所以您可以获得这些结果。尝试在索引字段中另外指定“label-a”和“label-b”作为未分析(原始)字段。然后像这样重写您的查询:

{
  "query": {
    "bool": {
        "should": {
             "match": {
                 "label-a.raw": {
                     "query": "apple",
                      "boost": 2
                        }
                    }
                },
      "must": [
        {
          "multi_match": {
            "query": "apple",
            "type": "most_fields",
            "fields": [
              "label-a",
              "label-b"
            ]
          }
        }
      ]
    }
  }
}

should子句将增强完全匹配的文档，您可能会首先将它们获取。尝试使用增加的数字，并在运行前检查查询。这只是个主意，您可以做什么