Skip Headers
Oracle® Coherence Getting Started Guide
Release 3.7

Part Number E18680-01
Go to Documentation Home
Home
Go to Book List
Book List
Go to Table of Contents
Contents
Go to Feedback page
Contact Us

Go to previous page
Previous
Go to next page
Next
View PDF

7 Cluster Services Overview

Coherence functionality is based on the concept of cluster services. Each cluster node can participate in (which implies both the ability to provide and to consume) any number of named services. These named services may exist, which is to say that they may be running on one or more other cluster nodes, or a cluster node can register new named services. Each named service has a service name that uniquely identifies the service within the cluster, and a service type, which defines what the service can do. There may be multiple named instances of each service type (other than the root Cluster service). By way of analogy, a service instance corresponds roughly to a database schema, and for data services, a hosted NamedCache corresponds roughly to a database table. While services can be fully configured, many applications only require the use the default set of services shipped with Coherence. There are several service types that are supported by Coherence.

Connectivity Services

Processing Services

Data Services

Regarding resources, a clustered service typically uses one daemon thread, and optionally has a thread pool that can be configured to provide the service with additional processing bandwidth. For example, the invocation service and the distributed cache service both fully support thread pooling to accelerate database load operations, parallel distributed queries, and agent invocations.

It is important to note that these are only the basic clustered services, and not the full set of types of caches provided by Coherence. By combining clustered services with cache features such as backing maps and overflow maps, Coherence can provide an extremely flexible, easily configured and powerful set of options for clustered applications. For example, the Near Cache functionality uses a Distributed Cache as one of its components.

Within a cache service, there exists any number of named caches. A named cache provides the standard JCache API, which is based on the Java collections API for key-value pairs, known as java.util.Map. The Map interface is the same API that is implemented by the Java Hashtable class, for example.