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

Very hot threads

When you are in trouble and your cluster works slower than usual and uses large amounts of CPU power, you know you need to do something to make it work again. This is when the hot threads API can give you the information necessary to find the root cause of your problems. A hot thread in this case is a Java thread that uses a high CPU volume and executes for longer periods of time. Such a thread doesn't mean that there is something wrong with Elasticsearch itself; it gives you information on what can be a possible hotspot and allows you to see which part of your deployment you need to look more deeply at, such as query execution or Lucene segments merging. The hot threads API returns information about which parts of the Elasticsearch code are hot spots from the CPU side or where Elasticsearch is stuck for some reason.

When using the hot threads API, you can examine all nodes, a selected few of them, or a particular node using the /_nodes/hot_threads or /_nodes/{node or nodes...