在弹性搜索中实现优先级搜索

Question

I'm trying to implement custom search in elastic search.

Problem statement is consider 3 documents inserted into elastic search with "names" field as array:

{
   id:1,
   names:["John Wick","Iron man"]
}
{
   id:2,
   names:["Wick Stone","Nick John"]
}
{
   id:3,
   names:["Manny Nick","Stone cold"]
}

when I search for "Nick" I want to boost or give priority to document starting with Nick so in this case document with id 2 should come first and then document with id 3 and also if I search for whole name "Manny Nick" doc with id 3 should be given priority.

Answer 1

In such case, you may want to modify/boost the score of search matched result for required criteria. For example, match the documents with names "Nick" and at the same time modify and boost the score of documents which contains names that start with Nick so that documents that match Nick and also starts with Nick will have higher score .

One of the way to achieve this is using Function Score Query. In the below query, search is made for keyword "Nick" and matched documents' score is modified and boosted for criteria "names that start with Nick" using Match Phrase Prefix Query with additional weight 20.

{
  "query": {
    "function_score": {
      "query": {
        "match": {
          "names": "Nick"
        }
      },
      "boost": "1",
      "functions": [
        {
          "filter": {
            "match_phrase_prefix": {
              "names": "Nick"
            }
          },
          "weight": 20
        }
      ],
      "boost_mode": "sum"
    }
  }
}

Testing:

Inserted data:

{
   id:1,
   names:["John Wick","Iron man"]
}
{
   id:2,
   names:["Wick Stone","Nick John"]
}
{
   id:3,
   names:["Manny Nick","Stone cold"]
}

Output:

{
    "took": 10,
    "timed_out": false,
    "_shards": {
        "total": 5,
        "successful": 5,
        "skipped": 0,
        "failed": 0
    },
    "hits": {
        "total": 2,
        "max_score": 20.693148,
        "hits": [
            {
                "_index": "stack_1",
                "_type": "1",
                "_id": "T9kn5WsBrk7qsVCmKBGH",
                "_score": 20.693148,
                "_source": {
                    "id": 2,
                    "names": [
                        "Wick Stone",
                        "Nick John"
                    ]
                }
            },
            {
                "_index": "stack_1",
                "_type": "1",
                "_id": "Ttkm5WsBrk7qsVCm2RF_",
                "_score": 20.287682,
                "_source": {
                    "id": 3,
                    "names": [
                        "Manny Nick",
                        "Stone cold"
                    ]
                }
            }
        ]
    }
}