ElasticSearch

Question

我目前正在使用 elasticsearch，我正在尝试从 Java 后端实现一个查询，该查询将不仅按术语而且按字段优先级从我的索引中查询文档。在我的索引中，我有包含术语和指定类型的字段的文档。

e.g 
term: "Flu Shot"
type: "procedure"

term: "Fluphenazine"
type: "drug"

我创建了一个按术语搜索的查询，弹性索引将 return 匹配该术语的最相关结果。我想要创建的功能是创建一个查询 return 结果匹配相同的术语，但按 'type' 字段的优先级排序。例如，当我输入“flu”时，我想首先获取类型为“procedure”的文档，然后是“drug”类型的文档。目前，由于许多药物以“流感”开头，因此索引 return 仅记录类型为“药物”的文件。

Answer 1

您可以使用 function_score.

The function_score allows you to modify the score of documents that are retrieved by a query. To use function_score, the user has to define a query and one or more functions, that compute a new score for each document returned by the query.

示例您的相关数据（使用 Elasticsearch 服务器 7.9）：

创建索引，添加文档

 PUT /example_index
 {
   "mappings": {
     "properties": {
       "term": {"type": "text" },
       "type": {"type": "keyword"}
     }
   }
 }

 PUT /_bulk
 {"create": {"_index": "example_index", "_id": 1}}
 {"term": "Flu Shot", "type": "procedure"}
 {"create": {"_index": "example_index", "_id": 2}}
 {"term": "Fluphenazine", "type": "drug"}
 {"create": {"_index": "example_index", "_id": 3}}
 {"term": "Flu Shot2", "type": "procedure"}
 {"create": {"_index": "example_index", "_id": 4}}
 {"term": "Fluphenazine2", "type": "drug"}

使用自定义评分逻辑查询文档

 GET /example_index/_search
 {
   "query": {
     "function_score": {
       "query": {
         "wildcard": {
           "term": {
             "value": "*flu*"
           }
         }
       },
       "functions": [
         {
           "filter": {
             "term": {
               "type": "procedure"
             }
           },
           "weight": 2
         },
         {
           "filter": {
             "term": {
               "type": "drug"
             }
           },
           "weight": 1
         }
       ]
     }
   }
 }

结果：

 {
   "took" : 2,
   "timed_out" : false,
   "_shards" : {
     "total" : 1,
     "successful" : 1,
     "skipped" : 0,
     "failed" : 0
   },
   "hits" : {
     "total" : {
       "value" : 4,
       "relation" : "eq"
     },
     "max_score" : 2.0,
     "hits" : [
       {
         "_index" : "example_index",
         "_type" : "_doc",
         "_id" : "1",
         "_score" : 2.0,
         "_source" : {
           "term" : "Flu Shot",
           "type" : "procedure"
         }
       },
       {
         "_index" : "example_index",
         "_type" : "_doc",
         "_id" : "3",
         "_score" : 2.0,
         "_source" : {
           "term" : "Flu Shot2",
           "type" : "procedure"
         }
       },
       {
         "_index" : "example_index",
         "_type" : "_doc",
         "_id" : "2",
         "_score" : 1.0,
         "_source" : {
           "term" : "Fluphenazine",
           "type" : "drug"
         }
       },
       {
         "_index" : "example_index",
         "_type" : "_doc",
         "_id" : "4",
         "_score" : 1.0,
         "_source" : {
           "term" : "Fluphenazine2",
           "type" : "drug"
         }
       }
     ]
   }
 }

您可以看到 type 设置为 procedure 的文档比 type 设置为 drug 的文档得分更高。这是因为我们为 function_score.

中的不同 type 分配了不同的权重

ElasticSearch - 按术语和字段优先级查询文档

ElasticSearch - query documents by term and field priority

elastic-stack