Introduction to Elasticsearch

So, what is Elasticsearch? First and foremost, Elasticsearch should not be viewed as a single, one-dimensional tool. Rather, it's a suite of tools that consists of a distributed database, a full-text search engine, and also an analytics engine. We will focus on the "database" part in this chapter, dealing with the "distributed" and "full-text search" parts later.

At its core, Elasticsearch is a high-level abstraction layer for Apache Lucene, a full-text search engine. Lucene is arguably the most powerful full-text search engine around; it is used by Apache Solr, another search platform similar to Elasticsearch. However, Lucene is very complex and the barrier to entry is high; thus Elasticsearch abstracts that complexity away into a RESTful API.

Instead of using Java to interact with Lucene directly, we can instead send HTTP requests to the API. Furthermore, Elasticsearch also provides many language-specific clients that abstract the API further into nicely-packaged objects and methods. We will be making use of Elasticsearch's JavaScript client to interact with our database.