Could you please help me to understand about coherence.
1: what is oracle weblogic server coherence,how it usefull in real time scenarios.
2) as I saw in oracle documents , it was in-memory grid ,is it was store business logic , in that case in weblogic cluster also we are using same in memory replication , how it differnt between weblogic cluster .
4) is coherance is a database.
Kindly help me above questions to understnad about oracle weblogic server coherence .is there any simple documents or liniks also fine.
Coherence provides fast and reliable access to the very frequently used data through caching.
It's In-Memory Data Grid is a data management system for application objects that are shared across multiple servers, require low response time, very high throughput, predictable scalability, continuous availability and information reliability.
Not all can be achieved by just a JVM effectively. Coherence compliments the already powerful JVM.
Maybe this (http://middlewaremagic.com/weblogic/?p=8351) can help you on the way.
This (http://docs.oracle.com/cd/E24290_01/coh.371/e22620/start.htm#CIHHAAIH) provides a good summary of what Coherence*Web does.
"Coherence*Web is an HTTP session management module dedicated to managing session state in clustered environments. Built on top of Oracle Coherence (Coherence), Coherence*Web:
- brings Coherence data grid's data scalability, availability, reliability, and performance to in-memory session management and storage.
- can configure fine-grained session and session attribute scoping by way of pluggable policies (see "Session and Session Attribute Scoping").
- can be deployed to many mainstream application servers such as Oracle GlassFish Server, Oracle WebLogic Server, IBM WebSphere, Tomcat, and so on (see "Supported Web Containers").
- can be deployed to many portal containers, including Oracle WebLogic Portal (see Chapter 10, "Using Coherence*Web with WebLogic Portal").
- allows storage of session data outside of the Java EE application server, freeing application server heap space and enabling server restarts without session data loss (see "Deployment Topologies").
- enables session sharing and management across different Web applications, domains and heterogeneous application servers (see "Session and Session Attribute Scoping").
- can be used in advanced session models (that is, Monolithic, Traditional, and Split Session) that define how the session state is serialized or deserialized in the cluster (see "Session Models")."