Oracle Mediator Component Characteristics Oracle Mediator Startup and Shutdown Lifecycle

Configuring High Availability for Oracle Fusion Middleware SOA Suite 5-37 with the SOA Service Infrastructure Java EE application. The runtime state for execution started by asynchronous interactions or involving parallel routing rules is maintained in the SOA runtime database. For details about administering Oracle Mediator, see the Oracle Fusion Middleware Administrator’s Guide for Oracle SOA Suite. ■ Synchronous and Asynchronous Interactions Oracle Mediator provides support for synchronous and asynchronous request-response interactions. In a synchronous interaction, the client making the request remains blocked, awaiting the response. In an asynchronous interaction, the client invokes the service but does not wait for the response. You can specify a time out period for an asynchronous interaction. ■ Sequential and Parallel Message Routing Oracle Mediator can route messages to their destinations either sequentially, or in parallel. – In a sequential routing, processing of data takes place in one single transaction. – In a parallel routing scenario, one transaction is used for en-queueing information, and another one for de-queuing it.

5.5.1.1 Oracle Mediator Component Characteristics

If a composite contains an Oracle Mediator component, SOA Service Infrastructure targets the component to the Oracle Mediator engine for deployment. None of the services provided by the Oracle Mediator engine system are singletons, therefore, Oracle Mediator engines can run in full active-active mode. The processing of messages by the worker threads in Oracle Mediator is transactional and relies on Oracle WebLogic Server transaction control service. Configure the appropriate transaction stores as recommended by WebLogic Server guidelines to guarantee recovery across failures in the WebLogic Server container. Additionally, Oracle Mediator’s engine does not contain any stateful Web modules or stateful session beans, therefore you are not required to configure any sort of session replication when running Oracle Mediator in active-active mode. The state of work and work-to-be processed is maintained by Oracle Mediator in the database. Therefore, it is critical that Oracle Mediators database be highly available. This requires configuring multi data sources for the SOA data source as described in Section 5.13.4, Running Oracle Fusion Middleware Configuration Wizard on SOAHOST1 to Create the SOA Domain . For information about multi data source configuration with Oracle RAC and the MDS repository, see Section 4.1.2, Using Multi Data Sources with Oracle RAC. External Dependencies Oracle Mediator depends on the following components: ■ SOA database for Mediator message and message state persistence ■ MDS repository for composite metadata store Both components must be available for Oracle Mediator to start or run properly.

5.5.1.2 Oracle Mediator Startup and Shutdown Lifecycle

When the Oracle SOA Service Infrastructure application starts, it initializes the Oracle Mediator engine and loads the composites from the MDS repository. If the composite contains any Oracle Mediator components, it targets them to the Oracle Mediator engine. At runtime, Oracle Mediator routing rules can be invoked through an inbound binding component or by another service engine. Graceful shutdown of the Oracle 5-38 Oracle Fusion Middleware High Availability Guide Mediator engine is initiated by the SOA Service Infrastructure and involves sending signals to in-flight instances and unloading of loaded components. Figure 5–24 illustrates Oracle Mediator Startup lifecyle. Figure 5–24 Oracle Mediator Startup Lifecyle

5.5.1.3 Oracle Mediator Request Flow