Oracle Coherence

In computing, Oracle Coherence – at its heart Oracle Coherence is Java-based in-memory data-grid or Caching product and addresses issues with traditional database-centric applications, to improve reliability, scalability and performance.

Coherence provides several core services:

• Replicated and partitioned data management and caching services - At its core Oracle Coherence is a highly scalable and fault tolerant distributed cache engine. Coherence is designed from the ground up to use a specialized scalable protocol and many inexpensive computers to create a cluster which can be seamlessly expanded to add more memory, processing power or both. As a result Coherence has no single point of failure and transparently failover if a cluster member fails. When a Coherence server is added or removed the cluster automatically re-balances to share the workload. As a result Coherence provides a highly available and predictably horizontally scalable infrastructure for managing application data. ^[1]
• Replicated data processing engine - In addition to caching Coherence provides a rich data processing model where by processing can be farmed out to where the data is, and results returned back to the client. By moving the processing to the data, processing too is highly scalable. Coherence also provides a robust event model allowing developers to interact with data as it changes.
• Rich client support - Oracle Coherence provides a rich client support set including clients written in Java, C++, .NET as well as other languages using REST. ^[2]. All of these features and more via the Coherence*Extend, core Coherence(REST) or both.

In addition Coherence provides a variety of mechanisms to integrate with other services using Oracle TopLink ^[3], using The Java Persistence API, ^[4], using Oracle Golden Gate ^[5] or almost any other platform using Coherence provided APIs.

Coherence also can be used to HTTP session management management via Coherence*Web ^[6] with Coherence*Web application services such as Oracle WebLogic Server, IBM WebSphere, Tomcat and others can reap the same benefits of performance, fault tolerance, and scalability as data.

Some Coherence usage patterns are open-source and are listed and supported though the Oracle Coherence incubator.^[7] These patterns implement features such as messaging, work distribution and data replication across WANs with Coherence.

Tangosol Inc. developed the original Coherence product. Oracle Corporation acquired Tangosol in April 2007, when Coherence had about 120 direct customers.^[8] It was also embedded in a few products from companies that included some of Oracle's competitors.^[9]

Other Information

The Oracle Coherence Knowledge Base
The Oracle Coherence v10 incubator page
Oracle Coherence 3.5 by Aleksander Seovic, Packt Press

See also

• Computer cluster
• Complex event processing
• Distributed computing
• Distributed transaction processing
• Extreme Transaction Processing
• Grid computing
• Transaction processing
• Distributed hash table

References

External links

• Oracle Coherence Product page
• Oracle Coherence User Forum