Boosting has no effect in a Boolean-filtered query in Elasticsearch

Question

I'm trying to add a boost to documents that match to a term filter. The basis is a Boolean/MatchAll query. But the boosting in my Elasticsearch query has no effect. All result scores are set to 1:

curl -XPOST localhost:9200/wiki_content/_search?pretty -d '
{
  "_source": [
    "title"
  ],
  "query": {
    "bool": {
      "must": [
        {
          "match_all": {}
        }
      ],
      "filter": [
        {
          "bool": {
            "should": [
              {
                "term": {
                  "title.keyword": {
                    "value": "Main Page",
                    "boost": 9
                  }
                }
              },
              {
                "term": {
                  "title.keyword": {
                    "value": "Top Page",
                    "boost": 999
                  }
                }
              }
            ]
          }
        }
      ]
    }
  }
}
'

However, when using a filtered query, the boosting works. But due to restrictions in my system I cannot use a filtered query. So is there any method to make the boosting in the original query work?

Answer 1

In the filter part of the query, boosting will have no effect, as the filters only job is to, ehhm, filter queries that match certain values. Try instead:

curl -XPOST localhost:9200/wiki_content/_search?pretty -d '
{
  "_source": [
    "title"
  ],
  "query": {
    "bool": {
      "must": [
        {
          "match_all": {}
        }
      ],
      "should": [
        {
          "term": {
            "title.keyword": {
              "value": "Main Page",
              "boost": 9
            }
          }
        },
        {
          "term": {
            "title.keyword": {
              "value": "Top Page",
              "boost": 999
            }
          }
        }
      ]
    }
  }
}
'

...moving the two term-queries directly into the should-clause in your top level bool query.