Book Image

Apache Solr Beginner's Guide

By : Alfredo Serafini
Book Image

Apache Solr Beginner's Guide

By: Alfredo Serafini

Overview of this book

<p>With over 40 billion web pages, the importance of optimizing a search engine's performance is essential.<br /><br />Solr is an open source enterprise search platform from the Apache Lucene project. Full-text search, faceted search, hit highlighting, dynamic clustering, database integration, and rich document handling are just some of its many features. Solr is highly scalable thanks to its distributed search and index replication.<br /><br />Solr is written in Java and runs as a standalone full-text search server within a servlet container such as Apache Tomcat or Jetty. Solr uses the Lucene Java search library at its core for full-text indexing and search, and has REST-like HTTP/XML and JSON APIs that make it usable with most popular programming languages. Solr's powerful external configuration allows it to be tailored to many types of application without Java coding, and it has a plugin architecture to support more advanced customization.<br /><br />With Apache Solr Beginner's Guide you will learn how to configure your own search engine experience. Using real data as an example, you will have the chance to start writing step-by-step, simple, real-world configurations and understand when and where to adopt this technology.<br /><br />Apache Solr Beginner's Guide will start by letting you explore a simple search over real data. You will then go through a step-by-step description that gives you the chance to explore several practical features. At the end of the book you will see how Solr is used in different real-world contexts.<br /><br />Using data from public domains like DBpedia, you will define several different configurations, exploring some of the most interesting Solr features, such as faceted search and navigation, auto-suggestion, and rich document indexing. You will see how to configure different analysers for handling different data types, without programming.<br /><br />You will learn the basics of Solr, focusing on real-world examples and practical configurations.</p>
Table of Contents (19 chapters)
Apache Solr Beginner's Guide
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Introducing stemming for query expansion


We have already adopted some file-based synonym query expansion. We can now adopt a stemmer-based approach, which is useful to add another level of flexibility, to intercept a certain amount of variance on user queries and needs.

Note

We call stemming the process by which we map the words derived from different forms of a certain original form to the same stem (or base, or root form). Words that share the same stem can be seen as a different surface for the same root, and they can be used as synonyms. This is useful to expand query adopting terms that are probably related because they have a similar form, for example, indexing for "painting" can produce the stem "paint" so that we are able to expand the query with results from the adoptions of terms "painter" or "painted". You should keep in mind that different languages may require quite different approaches, algorithms, and tools. If you want to read about stemming, I suggest you to start reading...