Book Image

Mastering Elasticsearch 5.x - Third Edition

By : Bharvi Dixit
Book Image

Mastering Elasticsearch 5.x - Third Edition

By: Bharvi Dixit

Overview of this book

Elasticsearch is a modern, fast, distributed, scalable, fault tolerant, and open source search and analytics engine. Elasticsearch leverages the capabilities of Apache Lucene, and provides a new level of control over how you can index and search even huge sets of data. This book will give you a brief recap of the basics and also introduce you to the new features of Elasticsearch 5. We will guide you through the intermediate and advanced functionalities of Elasticsearch, such as querying, indexing, searching, and modifying data. We’ll also explore advanced concepts, including aggregation, index control, sharding, replication, and clustering. We’ll show you the modules of monitoring and administration available in Elasticsearch, and will also cover backup and recovery. You will get an understanding of how you can scale your Elasticsearch cluster to contextualize it and improve its performance. We’ll also show you how you can create your own analysis plugin in Elasticsearch. By the end of the book, you will have all the knowledge necessary to master Elasticsearch and put it to efficient use.
Table of Contents (20 chapters)
Mastering Elasticsearch 5.x - Third Edition
About the Author
About the Reviewer
Customer Feedback

Query rewrite explained

We have already talked about scoring, which is valuable knowledge, especially when trying to improve the relevance of our queries. We also think that when debugging your queries, it is valuable to know how all the queries are executed; therefore, it is because of this that we decided to include this section on how query rewrite works in Elasticsearch, why it is used, and how to control it.

If you have ever used queries, such as the prefix query and the wildcard query, basically any query that is said to be multiterm, you've probably heard about query rewriting. Elasticsearch does that because of performance reasons. The rewrite process is about changing the original, expensive query to a set of queries that are far less expensive from Lucene's point of view, and thus speed up the query execution. The rewrite process is not visible to the client, but it is good to know that we can alter the rewrite process behavior. For example, let's look at what Elasticsearch does...