Improving the query relevance

Elasticsearch and search engines in general are used for searching. Of course, some use cases may require browsing some portion of the indexed data; sometimes, it is even needed to export whole query results. However, in most cases, scoring is one of the factors that play a major role in the search process. As we said in the Default Apache Lucene scoring explained section of Chapter 2, Power User Query DSL, Elasticsearch leverages the Apache Lucene library document scoring capabilities and allows you to use different query types to manipulate the score of results returned by our queries. What's more, we can change the low-level algorithm used to calculate the score that we will describe in the Altering Apache Lucene scoring section of Chapter 6, Low-level Index Control.

Given all this, when we start designing our queries, we usually go for the simplest query that returns the documents we want. However, given all the things we can do in Elasticsearch when...