Book Image

Oracle Coherence 3.5

By : Aleksandar Seovic
Book Image

Oracle Coherence 3.5

By: Aleksandar Seovic

Overview of this book

Scalability, performance, and reliability have to be designed into an application from the very beginning, as there may be substantial cost or implementation consequences if they need to be added down the line. This indispensible book will teach you how to achieve these things using Oracle Coherence, a leading data grid product on the market.Authored by leading Oracle Coherence authorities, this essential book will teach you how to use Oracle Coherence to build high-performance applications that scale to hundreds of machines and have no single points of failure. You will learn when and how to use Coherence features such as distributed caching, parallel processing, and real-time events within your application, and understand how Coherence fits into the overall application architecture. Oracle Coherence provides a solid architectural foundation for scalable, high-performance and highly available enterprise applications, through features such as distributed caching, parallel processing, distributed queries and aggregations, real-time events, and the elimination of single points of failure.However, in order to take full advantage of these features, you need to design your application for Coherence from the beginning. Based on the authors' extensive knowledge of Oracle Coherence, and how to use it in the real world, this book will provide you with all the information you need in order to leverage various Coherence features properly. It contains a collection of best practice-based solutions and mini-frameworks that will allow you to be more productive from the very beginning.The early chapters cover basics like installation guidelines and caching topologies, before moving on to the domain model implementation guidelines, distributed queries and aggregations, parallel processing, and real-time events. Towards the end, you learn how to integrate Coherence with different persistence technologies, how to access Coherence from platforms other than Java, and how to test and debug classes and applications that depend on Coherence.
Table of Contents (22 chapters)
Oracle Coherence 3.5
Credits
Foreword
About the author
Acknowledgements
About the co-authors
About the reviewers
Preface
12
The Right Tool for the Job
Index

Using indexes to improve query performance


Just as you can use indexes to improve query performance against a relational database, you can use them to improve the performance of a Coherence query. That is not to say that Coherence indexes are the same as database indexes—in fact, they are very different, and we'll discuss how indexes are implemented in Coherence shortly.

However, they are similar in the way they work, as they allow query processor to optimize queries by:

  1. Limiting the number of entries that have to be evaluated by the filter

  2. Avoiding the need for object deserialization by providing the necessary information within the index itself

Both of these features are very important and can have a significant impact on query performance. For that reason, it is recommended that you always create indexes for the attributes that you query on.

Anatomy of an Index

A Coherence index is an instance of a class that implements the com.tangosol.util.MapIndex interface:

public interface MapIndex {
 ...