# Problem with Dis Max Query **URL:** \ **Category:** Elasticsearch\ **Created:** [February 12, 2016, 3:56am UTC](https://discuss.elastic.co/t/problem-with-dis-max-query/41572 "2016-02-12T03:56:29Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![FisherKing](https://avatars.discourse-cdn.com/v4/letter/f/919ad9/32.png) [@FisherKing](https://discuss.elastic.co/u/FisherKing)\ **Post date:** [February 12, 2016, 3:56am UTC](https://discuss.elastic.co/t/problem-with-dis-max-query/41572/1 "2016-02-12T03:56:29Z")
I have this documents: { "firstfield" : "House" } { "firstfield" : "Red House" "secondfield" : "Blue House" } I want to query every field of a document. Only the field with the maximum score should set the final score for the document. For example when I search for 'House', the first document should have the highest score. I tried to achieve this with a dis max query. But it seems that there is always a boost if both fields contain the word. My query looks like this: "dis\_max" : { "tie\_breaker" : 0.0, "queries" : [ { "match" : { "firstfield" : { "query" : "House", "operator" : "AND" } } }, { "match" : { "secondfield" : { "query" : "House", "operator" : "AND" } } } ] } Anyone has a solution for my problem? I am using Elasticsearch 2.2. ---
**Author:** ![Ivan](https://avatars.discourse-cdn.com/v4/letter/i/df788c/32.png) [@Ivan](https://discuss.elastic.co/u/Ivan)\ **Post date:** [February 12, 2016, 11:02pm UTC](https://discuss.elastic.co/t/problem-with-dis-max-query/41572/2 "2016-02-12T23:02:11Z")
Why should the first document score higher? Can you post the explanation of the query? If the second document scores higher, then perhaps the term 'house' has a higher IDF value in the 'secondfield' field. Hard to tell without data. Ivan ---
**Author:** ![FisherKing](https://avatars.discourse-cdn.com/v4/letter/f/919ad9/32.png) [@FisherKing](https://discuss.elastic.co/u/FisherKing)\ **Post date:** [February 13, 2016, 4:42pm UTC](https://discuss.elastic.co/t/problem-with-dis-max-query/41572/3 "2016-02-13T16:42:26Z")
I gave you all the data I test with ( only 2 documents ). This query will have this scores: "dis\_max" : { "tie\_breaker" : 0.0, "queries" : [ { "match" : { "firstfield" : { "query" : "House", "type" : "boolean", "operator" : "AND" } } }, { "match" : { "secondfield" : { "query" : "House", "type" : "boolean", "operator" : "AND" } } } ] } "Red House" , "Blue House" =\> score 0.19178301 "House" =\> score 0.09415865 If I change the query to only 1 field ( which doesn't make much sense) I get different results: "dis\_max" : { "tie\_breaker" : 0.0, "queries" : [ { "match" : { "firstfield" : { "query" : "House", "type" : "boolean", "operator" : "AND" } } } ] } "House" =\> score 0.30685282 "Red House" , "Blue House" =\> score 0.19178301 If it would really be a pure disjunction max query it should return a score of 0.30685282 for House in both queries. This must be either a bug or the Dis Max Query is totally useless ☹ ---
**Author:** ![Ivan](https://avatars.discourse-cdn.com/v4/letter/i/df788c/32.png) [@Ivan](https://discuss.elastic.co/u/Ivan)\ **Post date:** [February 13, 2016, 5:39pm UTC](https://discuss.elastic.co/t/problem-with-dis-max-query/41572/4 "2016-02-13T17:39:39Z")
By data I mean the explanation of the query: [https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-explain.html](https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-explain.html) Is your environment sharded? If your documents are in different shards, the same terms might have different IDF values. If you have just a few test documents, scores will be more consistent in a single shard environment. Also, in your last query, the first document probably has a higher value because of length normalization. By default, a shorter field will be more relevant than a longer field, even if the term frequency is the same: [https://www.elastic.co/guide/en/elasticsearch/guide/master/scoring-theory.html#field-norm](https://www.elastic.co/guide/en/elasticsearch/guide/master/scoring-theory.html#field-norm) Reading Lucene explanations takes practice, but all the relevant details are in there. Ivan ---
**Author:** ![FisherKing](https://avatars.discourse-cdn.com/v4/letter/f/919ad9/32.png) [@FisherKing](https://discuss.elastic.co/u/FisherKing)\ **Post date:** [February 14, 2016, 5:57am UTC](https://discuss.elastic.co/t/problem-with-dis-max-query/41572/5 "2016-02-14T05:57:33Z")
Thank you for your help. I found out that IDF is the reason for this strange results. I think I was using only 1 shard the whole time. It's possible that the same term will get different IDF values even if only 1 shard is used? ---
**Author:** ![Ivan](https://avatars.discourse-cdn.com/v4/letter/i/df788c/32.png) [@Ivan](https://discuss.elastic.co/u/Ivan)\ **Post date:** [February 14, 2016, 5:10pm UTC](https://discuss.elastic.co/t/problem-with-dis-max-query/41572/6 "2016-02-14T17:10:12Z")
The IDF should be the same for each document in the shard. The IDF scores/weighs the search term, not the document. It sounds like documents are in different shards. You can view the number of shards in the GET settings API: [https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-get-settings.html](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-get-settings.html) Elasticsearch has a default of five shards. If you read the explanation, it will tell you which shard the document hit came from. You can also change the search type to do a distributed query then fetch. There is a performance hit since it needs to do another network roundtrip between the coordinating node and the data nodes, but I think it is slight. [https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-search-type.html#dfs-query-then-fetch](https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-search-type.html#dfs-query-then-fetch) The issue is minimized as you add more documents to an index. You normally see the issue in test indices with a handful of documents. Ivan ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 5, 2017, 11:16pm UTC](https://discuss.elastic.co/t/problem-with-dis-max-query/41572/7 "2017-07-05T23:16:31Z")