In the previous chapter, we looked at what Apache Lucene is, how its architecture looks, and how the analysis process is handled. In addition to these, we saw what Lucene query language is and how to use it. We also discussed Elasticsearch, its architecture, and core concepts. In this chapter, we will dive deep into Elasticsearch focusing on the Query DSL. We will first go through how Lucene scoring formula works before turning to advanced queries. By the end of this chapter, we will have covered the following topics:
How the default Apache Lucene scoring formula works
What query rewrite is
What query templates are and how to use them
How to leverage complicated Boolean queries
What are the performance implications of large Boolean queries
Which query you should use for your particular use case