如何提高Elasticsearch函数得分中的字段长度范数？ [英] How can I boost the field length norm in elasticsearch function score?

问题描述

我知道，弹性搜索在计算查询检索的文档的分数时会考虑字段的长度。字段越短，权重越高（请参见字段长度范数）。

I know that elasticsearch takes in account the length of a field when computing the score of the documents retrieved by a query. The shorter the field, the higher the weight (see The field-length norm).

我喜欢这种行为：当我搜索 iphone 时，我对更加感兴趣iphone 6 比中的废话配件：iphone 5 iphone 5s iphone 6 。

I like this behaviour: when I search for iphone I am much more interested in iphone 6 than in Crappy accessories for: iphone 5 iphone 5s iphone 6.

现在，我想尝试增强这些功能，比方说，我想使其重要性加倍。

Now, I would like to try to boost this stuff, let's say that I want to double its importance.

我知道可以使用功能得分，我猜我可以通过脚本得分。

I know that one can modify the score using the function score, and I guess that I can achieve what I want via script score.

我试图向得分添加另一个字段长度范数，如下所示：

I tried to add another field-length norm to the score like this:

    {
     "query": {
       "function_score": {
         "boost_mode": "replace",
         "query": {...},
         "script_score": {
             "script": "_score + norm(doc)"
         }
       }
     }
   }

但是我失败很严重，得到了这个错误： [元素[function_score]没有解析器]

But I failed badly, getting this error: [No parser for element [function_score]]

编辑：

我的第一个错误是我没有包装函数分数一个问题。现在，我编辑了上面的代码。我的新错误是

My first error was that I hadn't wrapped the function score in a "query". Now I edited the code above. My new error says

GroovyScriptExecutionException[MissingMethodException
[No signature of method: Script5.norm() is applicable for argument types:
(org.elasticsearch.search.lookup.DocLookup) values: 
[<org.elasticsearch.search.lookup.DocLookup@2c935f6f>]
Possible solutions: notify(), wait(), run(), run(), dump(), any()]]

编辑：我提供了第一个答案，但我希望有一个更好的答案

I provided a first answer, but I'm hoping for a better one

推荐答案

看来您可以使用类型 token_count 以及 field_value_factor 函数得分。

It looks like you could achieve that using a field of type token_count together with a field_value_factor function score.

因此，在字段映射中类似这样：

So, something like this in the field mapping:

"name": { 
  "type": "string",
  "fields": {
    "length": { 
      "type":     "token_count",
      "analyzer": "standard"
    }
  }
}

这将使用字段中的令牌数。如果要使用字符数，可以将分析器从 standard 更改为标记每个字符的自定义字符。

This will use the number of tokens in the field. If you want to use the number of characters, you can change the analyzer from standard to a custom one that tokenizes each character.

然后在查询中：

"function_score": {
  ...,
  "field_value_factor": {
    "field": "name.length",
    "modifier": "reciprocal"
  }
}

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