elasticsearch NGRAM和PostgreSQL卦搜索结果不匹配

Question

我crereated上elasticsearch指数相同的波纹管：

"settings" : { 
    "number_of_shards": 1, 
    "number_of_replicas": 0, 
    "analysis": { 
       "filter": { 
        "trigrams_filter": { 
         "type":  "ngram", 
         "min_gram": 3, 
         "max_gram": 3 
        } 
       }, 
       "analyzer": { 
        "trigrams": { 
         "type":  "custom", 
         "tokenizer": "standard", 
         "filter": [ 
          "lowercase", 
          "trigrams_filter" 
         ] 
        } 
       } 
    } 
}, 
"mappings": { 
    "issue": { 
     "properties": { 
      "description": { 
       "type":  "string", 
       "analyzer": "trigrams" 
      } 
     } 
    } 
} 

我的测试项目有波纹管：

"alici onay verdi basarili satisiniz gerceklesti diyor ama hesabima para transferi gerceklesmemis" 

"otomatik onay işlemi gecikmiş" 

"************* nolu iade islemi urun kargoya verilmedi zamaninda iade islemlerinde urun erorr hata veriyor" 

我已经用下列查询测试该指数：

GET issue/_search 
{ 
    "query": { 
     "match": { 
      "description":{ 
       "query": "otomatik onay istemi zamaninda gerceklesmemis" 
      } 
     } 
    } 
} 

and resu LT：与波纹管SQL响应上PostgreSQL的

{ 
     .... 
     "hits": { 
      .... 
       "max_score": 2.3507352, 
       "hits": [ 
          { 
           ....         
           "_score": 2.3507352, 
           "_source": { 
            "issue_id": "*******", 
            "description": "alici onay verdi basarili satisiniz gerceklesti diyor ama hesabima para transferi gerceklesmemis" 
              } 
          } 
         ] 
       } 
} 

但相同的数据的另一个结果：

SELECT 
    public.tbl_issue_descriptions_big.description, 
    similarity(description, 'otomatik onay islemi zamaninda gerceklesmemis') AS sml 
FROM 
    public.tbl_issue_descriptions_big 
WHERE 
    description %'otomatik onay islemi zamaninda gerceklesmemis' 
ORDER BY 
    sml DESC 
LIMIT 10 

结果是：

description           | sml 
======================================================|====== 
otomatik onay islemi gecikmis       |0,351852 

为什么这种差异造成的？

Answer 1

我不知道足够的Postgres给有一份合格的答卷（因为这还取决于被索引的文件，如果他们得分公式是完全一样的，我怀疑），但Elasticsearch有explain API和explain parameter在搜索中，这可以帮助您找出为什么某个文档以这种方式得分。