Elasticsearch 不会匹配精确的字符串

Question

我创建了一个带有完成提示的类别索引，但它的表现与我预期的不同。

curl -XPUT http://localhost:9200/categories/category/_mapping -d '{
    "category" : {
        "properties" : {
            "categoryDescription" : {
                "type" : "string"
            },
            "suggest" : {
                "type" : "completion",
                "analyzer" : "simple",
                "search_analyzer" : "simple",
                "payloads" : true
            }
        }
    }
}'

我有一个为 "Mexican Grocery Store" 编入索引的类别，当我搜索该字符串时，我得到的结果为零，只有一个建议结果：

{
    "query":{
        "fuzzy":{
            "categoryDescription":{
                "value":"mexican grocery store"
            }
        }
    },
    "from":0,
    "size":20,
    "suggest":{
        "category-suggest":{
            "text":"mexican grocery store",
            "completion":{
                "field":"suggest","fuzzy":{"fuzziness":2}
            }
        }
    }
}

{
    "took":19,
    "timed_out":false,
    "_shards":{"total":5,"successful":5,"failed":0},
    "hits":{
        "total":0,"max_score":null,"hits":[]
    },
    "suggest":{
        "category-suggest":[
            {
                "text":"mexican grocery store",
                "offset":0,
                "length":21,
                "options":[
                    {
                        "text":"Mexican Grocery Store",
                        "score":1.0,
                        "payload":{"id":5915028960051200}
                    }
                ]
            }
        ]
    }
}

不仅完全匹配的命中率为零，而且当我输入字符串 "Mexican" 时，在 [=20= 之前列出了一堆包含单词 "Medical" 的类别] 对我来说也没有任何意义的类别。

{
    "query":{
        "fuzzy":{
            "categoryDescription":{
                "value":"mexican"
            }
        }
    },
    "from":0,
    "size":20,
    "suggest":{
        "category-suggest":{
            "text":"mexican",
            "completion":{
                "field":"suggest","fuzzy":{"fuzziness":2}
            }
        }
    }
}

{
    "took":11,
    "timed_out":false,
    "_shards":{
        "total":5,
        "successful":5,
        "failed":0
    },
    "hits":{
        "total":25,
        "max_score":3.8085938,
        "hits":[
            {
                "_index":"categories",
                "_type":"category",
                "_id":"4993638215974912",
                "_score":3.8085938,
                "_source":{
                    "id":4993638215974912,
                    "categoryDescription":"Medical Spa",
                    "suggest":{
                        "input":["Medical Spa"],
                        "output":"Medical Spa",
                        "payload":{"id":4993638215974912}}}},
{"_index":"categories","_type":"category","_id":"6401013099528192","_score":3.8085938,"_source":{"id":6401013099528192,"categoryDescription":"Medical School","suggest":{"input":["Medical School"],"output":"Medical School","payload":{"id":6401013099528192}}}},{"_index":"categories","_type":"category","_id":"4712163239264256","_score":3.4429123,"_source":{"id":4712163239264256,"categoryDescription":"Medical Examiner","suggest":{"input":["Medical Examiner"],"output":"Medical Examiner","payload":{"id":4712163239264256}}}},{"_index":"categories","_type":"category","_id":"5978800634462208","_score":3.4429123,"_source":{"id":5978800634462208,"categoryDescription":"Medical Center","suggest":{"input":["Medical Center"],"output":"Medical Center","payload":{"id":5978800634462208}}}},{"_index":"categories","_type":"category","_id":"5415850681040896","_score":3.4429123,"_source":{"id":5415850681040896,"categoryDescription":"Medical Clinic","suggest":{"input":["Medical Clinic"],"output":"Medical Clinic","payload":{"id":5415850681040896}}}},{"_index":"categories","_type":"category","_id":"4852900727619584","_score":2.75433,"_source":{"id":4852900727619584,"categoryDescription":"Medical Billing Service","suggest":{"input":["Medical Billing Service"],"output":"Medical Billing Service","payload":{"id":4852900727619584}}}},{"_index":"categories","_type":"category","_id":"5352079006629888","_score":2.4411354,"_source":{"id":5352079006629888,"categoryDescription":"Mexican Restaurant","suggest":{"input":["Mexican Restaurant"],"output":"Mexican Restaurant","payload":{"id":5352079006629888}}}},{"_index":"categories","_type":"category","_id":"5915028960051200","_score":2.143557,"_source":{"id":5915028960051200,"categoryDescription":"Mexican Grocery Store","suggest":{"input":["Mexican Grocery Store","shop"],"output":"Mexican Grocery Store","payload":{"id":5915028960051200}}}},{"_index":"categories","_type":"category","_id":"6392217006505984","_score":2.0527549,"_source":{"id":6392217006505984,"categoryDescription":"Latin American Restaurant","suggest":{"input":["Latin American Restaurant"],"output":"Latin American Restaurant","payload":{"id":6392217006505984}}}},{"_index":"categories","_type":"category","_id":"5149768867119104","_score":2.0527549,"_source":{"id":5149768867119104,"categoryDescription":"Occupational Medical Physician","suggest":{"input":["Occupational Medical Physician"],"output":"Occupational Medical Physician","payload":{"id":5149768867119104}}}},{"_index":"categories","_type":"category","_id":"5157465448513536","_score":2.0527549,"_source":{"id":5157465448513536,"categoryDescription":"Central American Restaurant","suggest":{"input":["Central American Restaurant"],"output":"Central American Restaurant","payload":{"id":5157465448513536}}}},{"_index":"categories","_type":"category","_id":"6479078425100288","_score":2.0527549,"_source":{"id":6479078425100288,"categoryDescription":"American Football Field","suggest":{"input":["American Football Field"],"output":"American Football Field","payload":{"id":6479078425100288}}}},{"_index":"categories","_type":"category","_id":"4789129053208576","_score":1.9529084,"_source":{"id":4789129053208576,"categoryDescription":"Mexican Goods Store","suggest":{"input":["Mexican Goods Store","shop"],"output":"Mexican Goods Store","payload":{"id":4789129053208576}}}},{"_index":"categories","_type":"category","_id":"5275113192685568","_score":1.9138902,"_source":{"id":5275113192685568,"categoryDescription":"Medical Laboratory","suggest":{"input":["Medical Laboratory"],"output":"Medical Laboratory","payload":{"id":5275113192685568}}}},{"_index":"categories","_type":"category","_id":"5838063146106880","_score":1.7436681,"_source":{"id":5838063146106880,"categoryDescription":"Medical Group","suggest":{"input":["Medical Group"],"output":"Medical Group","payload":{"id":5838063146106880}}}},{"_index":"categories","_type":"category","_id":"4649491076481024","_score":1.7436681,"_source":{"id":4649491076481024,"categoryDescription":"American Restaurant","suggest":{"input":["American Restaurant"],"output":"American Restaurant","payload":{"id":4649491076481024}}}},{"_index":"categories","_type":"category","_id":"5458456756617216","_score":1.5311122,"_source":{"id":5458456756617216,"categoryDescription":"Traditional American Restaurant","suggest":{"input":["Traditional American Restaurant"],"output":"Traditional American Restaurant","payload":{"id":5458456756617216}}}},{"_index":"categories","_type":"category","_id":"6183309797228544","_score":1.5311122,"_source":{"id":6183309797228544,"categoryDescription":"Public Medical Center","suggest":{"input":["Public Medical Center"],"output":"Public Medical Center","payload":{"id":6183309797228544}}}},{"_index":"categories","_type":"category","_id":"6706677332049920","_score":1.5311122,"_source":{"id":6706677332049920,"categoryDescription":"Native American Goods Store","suggest":{"input":["Native American Goods Store","shop"],"output":"Native American Goods Store","payload":{"id":6706677332049920}}}},{"_index":"categories","_type":"category","_id":"6119538122817536","_score":1.3949344,"_source":{"id":6119538122817536,"categoryDescription":"Medical Supply Store","suggest":{"input":["Medical Supply Store","shop"],"output":"Medical Supply Store","payload":{"id":6119538122817536}}}}]},"suggest":{"category-suggest":[{"text":"mexican","offset":0,"length":7,"options":[{"text":"Medical Billing Service","score":1.0,"payload":{"id":4852900727619584}},{"text":"Medical Center","score":1.0,"payload":{"id":5978800634462208}},{"text":"Medical Clinic","score":1.0,"payload":{"id":5415850681040896}},{"text":"Medical Examiner","score":1.0,"payload":{"id":4712163239264256}},{"text":"Medical Group","score":1.0,"payload":{"id":5838063146106880}}]}]}}

Answer 1

您将字段 categoryDescription 索引为 string，因此 Elasticsearch 运行在您的输入上使用其标准分析器并将 Mexican Grocery Store 转换为三个标记，[mexican, grocery, store].

fuzzy 查询属于术语查询系列，也就是说，它在术语级别上运行，并且不会运行通过任何分析器。输入 Mexican Grocery Store 的模糊查询将尝试将这些词匹配为一个术语，而不是 3 个不同的词。它没有找到任何东西，因为完整的短语在索引中不作为一个术语存在。您可以向 categoryDescription 添加一个未分析的子字段或仅使用小写标记过滤器和运行此字段上的模糊查询以生成 "exact match".

对于第二部分，模糊查询不区分修改后的匹配（应用模糊性的地方）和精确匹配。在执行实际搜索之前，模糊术语会在内部与给定字段中所有术语的列表进行匹配并展开。在你的例子中，它变成了

"boolean": {
  "should": [
    {
      "term": {
        "categoryDescription": "medical"
      }
    },
    {
      "term": {
        "categoryDescription": "mexican"
      }
    }
  ]
}

由此，很清楚为什么会返回 Medical Spa 之类的内容。这些命中的分数也高于 Mexican Grocery Store，因此首先返回它们。我怀疑这是由于术语频率（Medical 比 Mexican 出现得更频繁）造成的，但是应该运行再次查询并启用 explain 才能确切地看到分数更高的原因。

如果要对模糊匹配应用惩罚，可以将模糊查询和术语查询包装到布尔查询中：

{
  "query": {
    "boolean": {
      "should": [
        {
          "fuzzy": {
            "categoryDescription": "mexican"
          }
        },
        {
          "term": {
            "categoryDescription": "mexican"
          }
        }
      ]
    }
  }
}

这会将只有 fuzzy 部分匹配的文档的分数减半（由于布尔查询的坐标因子）。

Elasticsearch 不会匹配精确的字符串

Elasticsearch won't match on exact string

elasticsearch

autosuggest