Filtered Query in Elasticsearch Java API

Question

I am little bit confused while creating Filtered query in Elasticsearch Java API. SearchRequestBuilder class has setPostFilter method, javadoc of this method clearly says that filter will be applied after Query is executed.

However, there is no setFilter method Or some other method which will allow to apply filter before
query is executed. How do I create filtered Query(which basically applies filter before query is executed) here? Am I missing something?

Answer 1

 FilteredQueryBuilder builder = 
 QueryBuilders.filteredQuery(QueryBuilders.termQuery("test", 
 "test"),FilterBuilders.termFilter("test","test"));

It will build the filtered query...To filteredQuery, first argument is query and second arguments is Filter.

Update: Filtered query is depreciated in elasticsearch 2.0+.refer

Hope it helps..!

Answer 2

QueryBuilders.filteredQuery is deprecated in API v. 2.0.0 and later.

Instead, filters and queries have "equal rights". FilterBuilders no longer exists and all filters are built using QueryBuilders.

To implement the query with filter only (in this case, geo filter), you would now do:

QueryBuilder query = QueryBuilders.geoDistanceQuery("location")
        .point(center.getLatitude(), center.getLongitude())
        .distance(radius, DistanceUnit.METERS);

// and then...
SearchResponse resp = client.prepareSearch(index).setQuery(query);

If you want to query by two terms, you would need to use boolQuery with must:

QueryBuilder query = QueryBuilders.boolQuery()
            .must(QueryBuilders.termQuery("user", "ben"))
            .must(QueryBuilders.termQuery("rank", "mega"));

// and then...
SearchResponse resp = client.prepareSearch(index).setQuery(query);

Answer 3

In case you just want to execute filter without query, you can do like this:

FilteredQueryBuilder builder = QueryBuilders.filteredQuery(QueryBuilders.matchAllQuery(),
   FilterBuilders.termFilter("username","stackoverflow"));

Ref: Filtering without a query

Answer 4

It seems that by wrapping the query (a BoolQueryBuilder object) by giving it as an argument to boolQuery().filter(..) and then setting that in the setQuery() as you suggested- then this can be achieved. The "score" key in the response is always 0 (though documents are found)

Be careful here! If the score is 0, the score has been calculated. That means the query is still in query context and not in filter context. In filter context the score is set to 1.0 (without calculation) source

To create a query in filter context without calculation of the score (score = 1.0) do the following (Maybe there is still a better way?):

QueryBuilder qb = QueryBuilders.constantScoreQuery(QueryBuilders.boolQuery().must(QueryBuilders.matchQuery("name", "blub)));

This returns the same results like:

GET /indexName/typeName/_search 
    {
      "filter": {
        "query": {
          "bool": {
            "must": [
              { "match": {
                "name": "blub"
              }}
            ]
          }
        }
      }
    }

Answer 5

Since FilteredQueryBuilder is deprecated in the recent versions, one can use the QueryBuilders.boolQuery() instead, with a must clause for the query and a filter clause for the filter.

import static org.elasticsearch.index.query.QueryBuilders.*;

QueryBuilder builder = boolQuery().must(termQuery("test", "test")).filter(  boolQuery().must(termQuery("test", "test")));