根据单词索引更改搜索顺序答案

【问题标题】：Change the search order based on word index根据单词索引更改搜索顺序
【发布时间】：2020-05-03 19:37:40
【问题描述】：

有什么方法可以增加文档开头的条款的权重？例如我有 3 个文件。

Medicine XXX
Sulpher This medicine contains sulpher and should be taken only after consultation with your doctor.

Medicine YYY
contains: sulpher Not recommended by most physicians

Medicine ZZZ
This medicine works like sulpher but does not contain sulpher at all.

文档 XXX 应列在搜索词“Sulpher”的顶部，因为这是该文档中的第一个词。如果 YYY 列在顶部就可以了，因为它与 XXX 相同。但ZZZ应该永远是最后一个。换句话说，位于“左侧”的术语应该比位于文档“右侧”的术语具有更高的优先级。

【问题讨论】：

标签： elasticsearch lucene

【解决方案1】：

您可以通过小写标准化术语位置来提升：

PUT sulphur
{
  "settings": {
    "analysis": {
      "normalizer": {
        "keyword_lowercase": {
          "type": "custom",
          "filter": ["lowercase"]
        }
      }
    }
  },
  "mappings": {
    "properties": {
      "text": {
        "type": "text",
        "fields": {
          "keyword": {
            "type": "keyword",
            "normalizer": "keyword_lowercase"
          }
        }
      }
    }
  }
}

POST sulphur/_doc
{"text":"This medicine works like sulpher but does not contain sulpher at all."}
POST sulphur/_doc
{"text":"contains: sulpher Not recommended by most physicians"}
POST sulphur/_doc
{"text":"Sulpher This medicine contains sulpher and should be taken only after consultation with your doctor."}

然后

GET sulphur/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "function_score": {
            "query": {
              "match": {
                "text": "sulpher"
              }
            },
            "script_score": {
              "script": """
                def pos = doc['text.keyword'].value.indexOf('sulpher');
                return Math.exp((2.0/(pos+1)))
              """
            },
            "boost_mode": "replace"
          }
        }
      ]
    }
  }
}

屈服

[
  {
    "_index":"sulphur",
    "_type":"_doc",
    "_id":"sf5S2nEBW-D5QnrWODvB",
    "_score":7.389056,
    "_source":{
      "text":"Sulpher This medicine contains sulpher and should be taken only after consultation with your doctor."
    }
  },
  {
    "_index":"sulphur",
    "_type":"_doc",
    "_id":"sP5S2nEBW-D5QnrWNjtw",
    "_score":1.1993961,
    "_source":{
      "text":"contains: sulpher Not recommended by most physicians"
    }
  },
  {
    "_index":"sulphur",
    "_type":"_doc",
    "_id":"r_5S2nEBW-D5QnrWNDuw",
    "_score":1.079959,
    "_source":{
      "text":"This medicine works like sulpher but does not contain sulpher at all."
    }
  }
]

【讨论】：

如果我有大量文档，脚本会缩放吗？
我想是的。 indexOf 操作并不复杂。