Fusion Middleware Control Help for WebLogic Server

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Create a Uniform Distributed Topic: Properties

Configuration Options     

Use this page to define properties for this uniform distributed topic.

Configuration Options

Name Description
Resource Type

The type of JMS system resource.

Name

The name of this uniform distributed topic.

Notes

Optional information that you can include to describe the configuration of this uniform distributed topic.

JNDI Name

The name used to bind a virtual destination to the JNDI tree. Applications can use the JNDI name to look up the virtual destination.

If not specified, then the destination is not bound into the JNDI namespace.

MBean Attribute (Does not apply to application modules) :
DistributedDestinationBean.JNDIName

Template

The JMS template from which the destination is derived. A template provides an efficient means of defining multiple destinations with similar configuration values.

Forwarding Policy

The uniform distributed topic message Forwarding Policy specifies whether a sent message is forwarded to all members.

The valid values are:

  • Replicated

    - The default. All physical topic members receive each sent message. If a message arrives at one of the physical topic members, a copy of this message is forwarded to the other members of that uniform distributed topic. A subscription on any one particular member will get a copy of any message sent to the uniform distributed topic logical name or to any particular uniform distributed topic member.

  • Partitioned

    - The physical member receiving the message is the only member of the uniform distributed topic that is aware of the message. When a message is published to the logical name of a Partitioned uniform distributed topic, it will only arrive on one particular physical topic member. Once a message arrives on a physical topic member, the message is not forwarded to the rest of the members of the uniform distributed destination, and subscribers on other physical topic members do not get a copy of that message. The Partitioned capability was added in WebLogic 10.3.4 (11gR1PS3).

A publisher that uses a logical JNDI name of a Replicated distributed topic is created on one member and every send call publishes messages to the same member regardless the value of the Load Balancing Enabled attribute. This is behavior is backward compatible with previous WebLogic Server releases when using a uniform distributed topic. Under the same conditions, a Partitioned distributed topic publishes to the same member only when the value of the Load Balancing Enabled attribute is set to false. If the value of the Load Balancing Enabled attribute is to true, a publisher to a Partitioned distributed topic publishes messages that are load balanced accross all the members of the uniform distributed topic.

Most new applications will use the new Partitioned forwarding policy in combination with a logical subscription topology on a uniform distributed topic that consists of: (1) a same named physical subscription created directly on each physical member, (2) a Client ID Policy of Unrestricted, and (3) a Subscription Sharing Policy of Sharable. WL 10.3.4 Message Driven Beans (MDBs) provides a Topic Messages Distribution Mode option to automatically setup this kind of topology.

MBean Attribute (Does not apply to application modules) :
UniformDistributedTopicBean.ForwardingPolicy

Changes take effect after you redeploy the module or restart the server.

Load Balancing Policy

Determines how messages are distributed to the members of this destination.

Choose from the following distribution techniques:

  • Round-Robin

    The system maintains an ordering of physical topic members within the set by distributing the messaging load across the topic members one at a time in the order that they are defined in the configuration file. Each WebLogic Server instance maintains an identical ordering, but may be at a different point within the ordering. If weights are assigned to any of the topic members in the set, then those members appear multiple times in the ordering.

  • Random

    The weight assigned to the topic members is used to compute a weighted distribution for the members of the set. The messaging load is distributed across the topic members by pseudo-randomly accessing the distribution. In the short run, the load will not be directly proportional to the weight. In the long run, the distribution will approach the limit of the distribution. A pure random distribution can be achieved by setting all the weights to the same value, which is typically set to 1.

MBean Attribute (Does not apply to application modules) :
UniformDistributedDestinationBean.LoadBalancingPolicy

Unit-of-Order Routing

Determines how a distributed destination member is selected as the destination for a message that is part of a unit-of-order. Hash, indicates that a message producer computes the member destination from the hashCode of the unit-of-order. PathService indicates that the configured Path Service determines the member destination.

Unit-of-Order Routing can be set programmatically with WLProducer, or administratively on the connection factory or destination.

Unit of Order Routing is not dynamically configurable.

MBean Attribute (Does not apply to application modules) :
UniformDistributedDestinationBean.UnitOfOrderRouting

Changes take effect after you redeploy the module or restart the server.


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