Introduction

To efficiently use ElasticSearch, it is very important to understand how it works.

The goal of this chapter is to give the readers an overview of the basic concepts of ElasticSearch and to be a quick reference for them. It's essential to understand the basics better so that you don't fall into the common pitfall about how ElasticSearch works and how to use it.

The key concepts that we will see in this chapter are: node, index, shard, mapping/type, document, and field.

ElasticSearch can be used both as a search engine as well as a data store.

A brief description of the ElasticSearch logic helps the user to improve performance, search quality, and decide when and how to optimize the infrastructure to improve scalability and availability.

Some details on data replications and base node communication processes are also explained.

At the end of this chapter, the protocols used to manage ElasticSearch are also discussed.