Book Image

Elasticsearch 5.x Cookbook - Third Edition

By : Alberto Paro
Book Image

Elasticsearch 5.x Cookbook - Third Edition

By: Alberto Paro

Overview of this book

Elasticsearch is a Lucene-based distributed search server that allows users to index and search unstructured content with petabytes of data. This book is your one-stop guide to master the complete Elasticsearch ecosystem. We’ll guide you through comprehensive recipes on what’s new in Elasticsearch 5.x, showing you how to create complex queries and analytics, and perform index mapping, aggregation, and scripting. Further on, you will explore the modules of Cluster and Node monitoring and see ways to back up and restore a snapshot of an index. You will understand how to install Kibana to monitor a cluster and also to extend Kibana for plugins. Finally, you will also see how you can integrate your Java, Scala, Python, and Big Data applications such as Apache Spark and Pig with Elasticsearch, and add enhanced functionalities with custom plugins. By the end of this book, you will have an in-depth knowledge of the implementation of the Elasticsearch architecture and will be able to manage data efficiently and effectively with Elasticsearch.
Table of Contents (25 chapters)
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Dedication
Preface

Executing an aggregation


Elasticsearch provides several functionalities other than search; it allows executing statistics and real-time analytics on searches via the aggregations.

Getting ready

You need an up-and-running Elasticsearch installation, as we described in the Downloading and installing Elasticsearch recipe in Chapter 2, Downloading and Setup.

To execute curl via the command line, you need to install curl for your operative system.

To correctly execute the command, you need an index populated with the script (chapter_08/populate_aggregations.sh) available in the online code.

How to do it...

For executing an aggregation, we will perform the following steps:

  1. We want to compute the top 10 tags by name. We can obtain this from the command line, executing a similar query with aggregations as follows:

            curl -XGET 'http://127.0.0.1:9200/test-index/test-type/_search?  
            pretty&size=0' -d '{ 
                "query": { 
                    "match_all": {} 
          ...