Boosting in more like this elasticsearch

Question

I was trying to do a simple POC for related items using the elasticsearch's http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-mlt-query.html#query-dsl-mlt-query,

But I was not getting how to use the boosting so that the important fields in my document carry more weight in the final output. Also how can I apply a boost in more like this query such that the recent documents carry more weight.

Thanks.

Answer 1

One way to achieve specific boosts if a document is more like a particular doc or if the match is on particular field you can use multiple mlt queries and wrap them in a should clause(bool)/dis_max based on whether you want "sum of"/"max of" logic while scoring:

Example using dis_max would be :

POST  test_index/_search?explain=true
{
    "fields": [
       "field1",
       "field2"
    ], 
    "query": { 
        "dis_max": {
           "queries": [
               {
                "more_like_this" : {
                    "fields" : ["field1"],
                    "like_text" : "this is  some text",
                    "min_term_freq" : 1,
                    "max_query_terms" : 2,
                    "boost": 20
                }
               },
               {
                "more_like_this" : {
                    "fields" : ["field2"],
                    "like_text" : "this is some other text",
                    "min_term_freq" : 1,
                    "max_query_terms" : 2,
                    "boost": 20
                }
               }
            ]
        }
    }
}