如何在Elasticsearch中使用ngram时控制结果的评分或排序？

Question

我正在使用Elasticsearch 6.X ..

我创建了一个索引类型为test_index的索引doc，如下所示：

PUT /test_index
{
  "settings": {
    "number_of_shards": 1,
    "number_of_replicas": 0,
    "analysis": {
      "analyzer": {
        "my_analyzer": {
          "type": "custom",
          "tokenizer": "my_ngram_tokenizer"
        }
      },
      "tokenizer": {
        "my_ngram_tokenizer": {
          "type": "nGram",
          "min_gram": "1",
          "max_gram": "7",
          "token_chars": [
            "letter",
            "digit",
            "punctuation"
          ]
        }
      }
    }
  },
  "mappings": {
    "doc": {
      "properties": {
        "my_text": {
          "type": "text",
          "fielddata": true,
          "fields": {
            "ngram": {
              "type": "text",
              "fielddata": true,
              "analyzer": "my_analyzer"
            }
          }
        }
      }
    }
  }
}

我索引数据如下：

PUT /text_index/doc/1
{
    "my_text": "ohio"
}
PUT /text_index/doc/2
{
    "my_text": "ohlin"
}
PUT /text_index/doc/3
{
    "my_text": "john"
}

然后我用搜索查询：

{
  "query": {
    "bool": {
      "must": [
        {
          "multi_match": {
            "query": "oh",
            "fields": [
              "my_text^5",
              "my_text.ngram"
            ]
          }
        }
      ]
    }
  }
}

并得到了回应：

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "failed": 0
  },
  "hits": {
    "total": 5,
    "max_score": 1.0042334,
    "hits": [
      {
        "_index": "test_index",
        "_type": "doc",
        "_id": "1",
        "_score": 1.0042334,
        "_source": {
          "my_text": "ohio"
        }
      },
      {
        "_index": "test_index",
        "_type": "doc",
        "_id": "3",
        "_score": 0.97201055,
        "_source": {
          "my_text": "john"
        }
      },
      {
        "_index": "test_index",
        "_type": "doc",
        "_id": "2",
        "_score": 0.80404717,
        "_source": {
          "my_text": "ohlin"
        }
      }
    ]
  }
}

在这里，我们可以看到当我搜索oh时，我得到了顺序的结果：

-> ohio
-> john
-> ohlin

但是，我希望以一种给匹配前缀提供更高优先级的方式对结果进行评分和排序：

-> ohio
-> ohlin
-> john

我怎样才能达到这样的效果？我可以采取什么方法？提前致谢。