一尘不染

Elasticsearch词组建议者向我建议索引中不存在的建议

elasticsearch

我有一个Elasticsearch索引,其中有一些数据。我实现了该did-you- mean功能,所以当用户写错拼写的东西时,它可能会收到带有正确单词的建议。

之所以使用短语建议者,是因为我需要一些简短的短语(例如名称)的建议,问题是索引中不存在某些建议。

例:

document in the index: coding like a master
search: Codning like a boss
suggestion: <em>coding</em> like a boss
search result: not found

我的问题是,索引中没有与指定建议匹配的词组,因此它向我推荐了不存在的词组,因此会给我一个未找到的搜索词。

我该怎么办?短语建议者是否应该为索引中实际存在的短语提供建议?

在这里,我将保留相应的查询,映射和设置,以防万一。

设置和映射

{
  "settings": {
    "index": {
      "number_of_shards": 3,
      "number_of_replicas": 1,
      "search.slowlog.threshold.fetch.warn": "2s",
      "index.analysis.analyzer.default.filter.0": "standard",
      "index.analysis.analyzer.default.tokenizer": "standard",
      "index.analysis.analyzer.default.filter.1": "lowercase",
      "index.analysis.analyzer.default.filter.2": "asciifolding",
      "index.priority": 3,
      "analysis": {
        "analyzer": {
          "suggests_analyzer": {
            "tokenizer": "lowercase",
            "filter": [
              "lowercase",
              "asciifolding",
              "shingle_filter"
            ],
            "type": "custom"
          }
        },
        "filter": {
          "shingle_filter": {
            "min_shingle_size": 2,
            "max_shingle_size": 3,
            "type": "shingle"
          }
        }
      }
    }
  },
  "mappings": {
    "my_type": {
      "properties": {
        "suggest_field": {
          "analyzer": "suggests_analyzer",
          "type": "string"
        }
      }
    }
  }
}

询问

{
  "DidYouMean": {
    "text": "Codning like a boss",
    "phrase": {
      "field": "suggest_field",
      "size": 1,
      "gram_size": 1,
      "confidence": 2.0
    }
  }
}

谢谢你的帮助。


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2020-06-22

共1个答案

一尘不染

这实际上是预期的。如果您使用analytics
api
分析文档,则可以更好地了解正在发生的事情。

GET suggest_index/_analyze?text=coding like a master&analyzer=suggests_analyzer

这是输出

{
   "tokens": [
      {
         "token": "coding",
         "start_offset": 0,
         "end_offset": 6,
         "type": "word",
         "position": 1
      },
      {
         "token": "coding like",
         "start_offset": 0,
         "end_offset": 11,
         "type": "shingle",
         "position": 1
      },
      {
         "token": "coding like a",
         "start_offset": 0,
         "end_offset": 13,
         "type": "shingle",
         "position": 1
      },
      {
         "token": "like",
         "start_offset": 7,
         "end_offset": 11,
         "type": "word",
         "position": 2
      },
      {
         "token": "like a",
         "start_offset": 7,
         "end_offset": 13,
         "type": "shingle",
         "position": 2
      },
      {
         "token": "like a master",
         "start_offset": 7,
         "end_offset": 20,
         "type": "shingle",
         "position": 2
      },
      {
         "token": "a",
         "start_offset": 12,
         "end_offset": 13,
         "type": "word",
         "position": 3
      },
      {
         "token": "a master",
         "start_offset": 12,
         "end_offset": 20,
         "type": "shingle",
         "position": 3
      },
      {
         "token": "master",
         "start_offset": 14,
         "end_offset": 20,
         "type": "word",
         "position": 4
      }
   ]
}

如您所见,为文本生成了一个令牌“编码”,因此它在您的索引中。这 并不是在
建议您不要在索引中。如果您严格地想要短语搜索,那么您可能要考虑使用关键字标记器。例如,如果您将映射更改为类似

{
  "settings": {
    "index": {
      "analysis": {
        "analyzer": {
          "suggests_analyzer": {
            "tokenizer": "lowercase",
            "filter": [
              "lowercase",
              "asciifolding",
              "shingle_filter"
            ],
            "type": "custom"
          },
          "raw_analyzer": {
            "tokenizer": "keyword",
            "filter": [
              "lowercase",
              "asciifolding"
            ]
          }
        },
        "filter": {
          "shingle_filter": {
            "min_shingle_size": 2,
            "max_shingle_size": 3,
            "type": "shingle"
          }
        }
      }
    }
  },
  "mappings": {
    "my_type": {
      "properties": {
        "suggest_field": {
          "analyzer": "suggests_analyzer",
          "type": "string",
          "fields": {
            "raw": {
              "analyzer": "raw_analyzer",
              "type": "string"
            }
          }
        }
      }
    }
  }
}

那么此查询将为您提供预期的结果

{
  "DidYouMean": {
    "text": "codning lke a master",
    "phrase": {
      "field": "suggest_field.raw",
      "size": 1,
      "gram_size": 1
    }
  }
}

它不会显示 “像老板一样编码”的 任何内容。

编辑1

2)从您的评论以及在我自己的数据集上运行一些短语建议中,我觉得更好的方法是使用collate选项phrase suggester提供,以便我们可以针对a检查每个建议query并仅在返回时才给出建议索引中的任何文档。我还添加stemmers了映射以仅考虑词根。我正在使用,light_english因为它的攻击性较小。关于更多

映射器的分析器部分现在看起来像这样

 "analysis": {
     "analyzer": {
         "suggests_analyzer": {
             "tokenizer": "standard",
             "filter": [
                 "lowercase",
                 "english_possessive_stemmer",
                 "light_english_stemmer",
                 "asciifolding",
                 "shingle_filter"
             ],
             "type": "custom"
         }
     },
     "filter": {
         "light_english_stemmer": {
             "type": "stemmer",
             "language": "light_english"
         },
         "english_possessive_stemmer": {
             "type": "stemmer",
             "language": "possessive_english"
         },
         "shingle_filter": {
             "min_shingle_size": 2,
             "max_shingle_size": 4,
             "type": "shingle"
         }
     }
 }

现在,此查询将为您提供所需的结果。

{
   "suggest" : {
     "text" : "appel on the tabel",
     "simple_phrase" : {
       "phrase" : {
         "field" :  "suggest_field",
         "size" :   5,
         "collate": {
           "query": { 
             "inline" : {
               "match_phrase": {
                   "{{field_name}}" : "{{suggestion}}" 
               }
             }
           },
           "params": {"field_name" : "suggest_field"}, 
           "prune": false
         }
       }
     }
   },
   "size": 0
 }

这将使您回到 桌上的苹果。 这里使用match_phrase查询,它将对索引运行每个建议的短语。"prune" : true无论匹配如何,您都可以查看并建议所有结果。您可能要考虑使用stop过滤器来避免停用词。

希望这可以帮助!!

2020-06-22