Book Image

Advanced Elasticsearch 7.0

By : Wai Tak Wong
Book Image

Advanced Elasticsearch 7.0

By: Wai Tak Wong

Overview of this book

Building enterprise-grade distributed applications and executing systematic search operations call for a strong understanding of Elasticsearch and expertise in using its core APIs and latest features. This book will help you master the advanced functionalities of Elasticsearch and understand how you can develop a sophisticated, real-time search engine confidently. In addition to this, you'll also learn to run machine learning jobs in Elasticsearch to speed up routine tasks. You'll get started by learning to use Elasticsearch features on Hadoop and Spark and make search results faster, thereby improving the speed of query results and enhancing the customer experience. You'll then get up to speed with performing analytics by building a metrics pipeline, defining queries, and using Kibana for intuitive visualizations that help provide decision-makers with better insights. The book will later guide you through using Logstash with examples to collect, parse, and enrich logs before indexing them in Elasticsearch. By the end of this book, you will have comprehensive knowledge of advanced topics such as Apache Spark support, machine learning using Elasticsearch and scikit-learn, and real-time analytics, along with the expertise you need to increase business productivity, perform analytics, and get the very best out of Elasticsearch.
Table of Contents (25 chapters)
Free Chapter
Section 1: Fundamentals and Core APIs
Section 2: Data Modeling, Aggregations Framework, Pipeline, and Data Analytics
Section 3: Programming with the Elasticsearch Client
Section 4: Elastic Stack
Section 5: Advanced Features

Meta fields in mapping

Some meta fields can be defined in the mapping to customize the indexing operation. We'll list some of the important ones and describe their usage:

  • _meta: This is for user-defined metadata. Developers can use it to store the application-specific metadata.
  • _routing: You can configure the routing value in the mapping to require all subsequent related operations to have the routing value specified.
  • _source: By default, _source is enabled and the source document is stored. If the _source is disabled by a user, then the source document is not retained. The benefit to this is that it saves some storage space. The drawback is that there are no more supports for the document to reindex, update, and highlight when executing a search. Think carefully before deciding.

_meta and _routing can be updated, but _source cannot be updated. Let us use the following...