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Advanced Queuing - Oracle

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Messaging Gateway Architecture<br />

Through the administration package, you configure the gateway agent with the<br />

proper user name, password, and database connect string of the <strong>Oracle</strong> database in<br />

order for the agent to create connections to the database. You can also call<br />

procedures in the package to assign the maximum number of database connections<br />

and the size of the memory heap to the agent.<br />

For the gateway agent to propagate messages to and from a non-<strong>Oracle</strong> messaging<br />

system, a messaging system link, which represents a communication channel<br />

between the agent and the non-<strong>Oracle</strong> messaging system, must be created using the<br />

administration package. Multiple messaging system links can be configured in the<br />

agent.<br />

All non-<strong>Oracle</strong> queues that are involved in propagation must be registered using<br />

the administration package. Registering a non-<strong>Oracle</strong> queue in the gateway<br />

configuration does not create the physical queue in the non-<strong>Oracle</strong> messaging<br />

system, but only records information about the queue, such as the messaging<br />

system link to access it, its native name, and its domain (queue or topic). The<br />

physical queue must be created through the administration interfaces of the<br />

non-<strong>Oracle</strong> messaging system.<br />

With messaging system links and non-<strong>Oracle</strong> queues configured, you can create<br />

propagation jobs to set up message propagation. A propagation job in Messaging<br />

Gateway consists of a propagation subscriber and a propagation schedule. A<br />

propagation subscriber is created to define the source queue and the destination<br />

queue of a propagation job. You manipulate the propagation schedule associated<br />

with the propagation job to control when the propagation job is processed.<br />

Messaging Gateway provides database views for gateway administrators to query<br />

and check the current configuration information, the gateway agent running status,<br />

and the propagation job status and statistics.<br />

Gateway configuration can be changed independent of whether the gateway agent<br />

is running or shut down. If the agent is running, the administration procedures<br />

send notifications to the agent for configuration changes. The agent will<br />

dynamically alter its configuration for most configuration changes, although some<br />

require that the agent be shut down and restarted before they take effect. All the<br />

procedures in the administration package are serialized to guarantee that the<br />

gateway agent receives notifications for the configuration changes in the same order<br />

they are made.<br />

See Also: <strong>Oracle</strong>9i Supplied PL/SQL Packages and Types Reference for<br />

more information on DBMS_MGWADM<br />

18-4 <strong>Oracle</strong>9i Application Developer’s Guide - <strong>Advanced</strong> <strong>Queuing</strong>

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