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

Cache aside


Perhaps the most common caching pattern in use today is cache aside. If you have ever used a standard map to implement primitive caching yourself, you are already familiar with this approach—you check if a piece of data is in the cache and if it isn't then you load it from the database and put it in the cache for future requests. When the data is subsequently updated, it is up to the application to either invalidate the cache or update it with the new value.

Applications that have a well-defined data access object (DAO) layer can easily treat caching as a cross-cutting concern. The DAO can be wrapped by a proxy that performs the cache-aside operations. This can be as simple as the use of java.util.Proxy or as advanced as the use of AspectJ or any other AOP framework.

There are some consequences of cache aside that should be kept in mind:

  • If multiple threads require access to the same piece of data that is not in the cache, it may result in multiple redundant reads to the database...