WebSphere WebSphere Application Server Express, Version 6.0.x Operating Systems: AIX, HP-UX, Linux, Solaris, Windows

Enabling a provider to stream messages to cloned durable subscriptions

Use this task to enable a provider to stream messages to consumers ahead of their message requests. This is most often used by publish/subscribe consumers to provide a performance enhancement.

Why and when to perform this task

To indicate that a provider must stream messages to consumers, you can set the Read ahead property to Enabled. This property can be set on a connection factory to specify the behavior for all connections created using that connection factory. The property can also be set on JMS topics, to enable different behavior when sending messages to different JMS topics from the same connection.

You are recommended to leave this property set to Default, which enables the messaging provider to decide whether or not it should stream messages to consumers. The messaging provider makes this decision based on the environment in which the durable subscriber is running. You should only set this property to enable message streaming if you are sure that a durable subscription is used by only one consumer at a time.

Messages that are streamed to the consumer but are not consumed before the consumer disconnects are unlocked when the consumer closes. Only then do those messages become available for consumption by other consumers.

To force the messaging provider to stream messages to cloned durable subscriptions, use the administrative console to complete the following steps to change the connection factory:

Steps for this task

  1. Display the JMS connection factory; for example, as described in Configuring a unified JMS connection factory for the default messaging provider. All clones of a durable subscriber use the same JMS connection factory.
  2. Set the Read ahead property to Enabled.
  3. Click OK.
  4. Save your changes to the master configuration.

Task topic

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Last updated: 2 Aug 2005
http://publib.boulder.ibm.com/infocenter/ws60help/index.jsp?topic=/com.ibm.websphere.pmc.express.doc\tasks\tjo0034_.html

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