elasticsearch - Elasticsearch 5.6 multi_match搜索，edge_ngram返回零结果

Question

我在Elasticsearch中有如下文件:

{
  "_index" : "demo_index",
  "_type" : "doc",
  "_id" : "user_122",
  "_version" : 4,
  "found" : true,
  "_source" : {
    "id" : 1520488,
    "doc_type" : "user",
    "user_email" : "neeraj@test.com",
    "user_first_name" : "Neeraj",
    "user_last_name" : "Goel"
  }
}

接下来是返回零结果的查询。
注意:仅在将全名分为索引中的user_first_name和user_last_name字段时，才出现这种情况。

{
  "index": "demo_index",
  "type": "doc",
  "body": {
    "from": 0,
    "size": "200",
    "query": {
      "bool": {
        "must": [
          {
            "term": {
              "doc_type": "user"
            }
          },
          {
            "term": {
              "user_status": 1
            }
          },
          {
            "multi_match": {
              "query": "neeraj goel",
              "operator": "AND",
              "fuzziness": "AUTO",
              "fields": [
                "user_first_name.edge_ngram",
                "user_last_name.edge_ngram"
              ]
            }
          }
        ],
        "should": {
          "prefix": {
            "user_first_name.sort": "neeraj goel"
          }
        }
      }
    },
    "sort": {
      "_score": {
        "order": "desc"
      }
    }
  }
}

索引中使用的edge_ngram设置为:

{
  "edge_ngram_tokenizer": {
    "token_chars": [
      "letter"
    ],
    "min_gram": "2",
    "type": "edge_ngram",
    "max_gram": "8"
  }
}

对应:

{
  "user_first_name": {
    "type": "text",
    "fields": {
      "edge_ngram": {
        "type": "text",
        "analyzer": "edge_ngram_analyzer"
      },
      "ngram": {
        "type": "text",
        "analyzer": "ngram_analyzer"
      },
      "raw": {
        "type": "keyword"
      }
    },
    "analyzer": "standard"
  }
}

我无法弄清楚我的查询出了什么问题，因为如上所述，当文档中没有user_last_name时，查询工作正常。
谁能帮我解决这个问题。
谢谢。

Answer 1

由于您的索引设置和映射还不完整，并且不清楚要实现的目标，因此我添加了一个示例，该示例在您的用例附近有效并且可以理解，一旦添加更多数据，该示例便会更改。
索引定义以及映射和设置

{
    "settings": {
        "analysis": {
            "analyzer": {
                "edge_ngram_analyzer": {
                    "tokenizer": "edge_ngram_tokenizer"
                },
                "ngram_analyzer": {
                    "tokenizer": "ngram_tokenizer"
                }
            },
            "tokenizer": {
                "edge_ngram_tokenizer": {
                    "token_chars": [
                        "letter"
                    ],
                    "min_gram": "2",
                    "type": "edge_ngram",
                    "max_gram": "8"
                },
                "ngram_tokenizer": {
                    "token_chars": [
                        "letter"
                    ],
                    "min_gram": "2",
                    "type": "ngram",
                    "max_gram": "8"
                }
            }
        },
        "index.max_ngram_diff": 10 // note this
    },
    "mappings": {
        "properties": {
            "user_first_name": {
                "type": "text",
                "fields": {
                    "edge_ngram": {
                        "type": "text",
                        "analyzer": "edge_ngram_analyzer"
                    },
                    "ngram": {
                        "type": "text",
                        "analyzer": "ngram_analyzer"
                    },
                    "raw": {
                        "type": "keyword"
                    }
                },
                "analyzer": "standard"
            },
            "user_last_name": {
                "type": "text",
                "fields": {
                    "edge_ngram": {
                        "type": "text",
                        "analyzer": "edge_ngram_analyzer"
                    },
                    "ngram": {
                        "type": "text",
                        "analyzer": "ngram_analyzer"
                    },
                    "raw": {
                        "type": "keyword"
                    }
                },
                "analyzer": "standard"
            }
        }
    }
}

并将示例文档添加到索引

{
   "user_first_name" : "Neeraj",
   "user_last_name" : "Goel"
}

并搜索查询

{
    "query": {
        "bool": {
            "must": [
                {
                    "multi_match": {
                        "query": "neeraj goel",
                        "operator": "or", // note this
                        "fuzziness": "AUTO",
                        "fields": [
                            "user_first_name.edge_ngram",
                            "user_last_name.edge_ngram"
                        ]
                    }
                }
            ],
            "should": {
                "prefix": {
                    "user_first_name.sort": "neeraj goel"
                }
            }
        }
    }
}

和搜索结果

"hits": [
            {
                "_index": "myindexedge",
                "_type": "_doc",
                "_id": "1",
                "_score": 1.0500396,
                "_source": {
                    "user_first_name": "Neeraj",
                    "user_last_name": "Goel"
                }
            }
        ]