PK54128: FUNCTIONALITY IN WEBSPHERE APPLICATION SERVER 6.1 TO TUNE THE TARGET OF A JMS ACTIVATION SPEC DOES NOT EXIST IN 6.0.

APAR status

• Closed as program error.

Error description

• In Websphere application Server 6.1 it is possible to tune
  the targets of the JMS activation specification.  This functiona
  lity does not currently exist with WebSphere application
  Server 6.0x.  This apar will add this functionality via a new
  custom property for the j2c activation specification.
  The logic of choosing a connection for an MDB after the change
  is summarised as follows:
  - Is there a local ME for the specified bus? If so use it.
  - Is an ME matching the target specification available?
  - Is target significance preferred? If so us any ME for the bus.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of the default messaging provider for  *
  *                 WebSphere Application Server V6.0, with      *
  *                 message driven beans connecting to a         *
  *                 service integration bus via an activation    *
  *                 specification.                               *
  ****************************************************************
  * PROBLEM DESCRIPTION: In WebSphere Application Server V6.0    *
  *                      it is not possible to influence which   *
  *                      messaging engine a message driven       *
  *                      bean will connect to, when there is     *
  *                      no messaging engine running in the      *
  *                      application server that hosts the       *
  *                      bean.                                   *
  *                      There are a number of reasons why       *
  *                      this may be required. In some highly    *
  *                      available topologies it may be          *
  *                      necessary to force a message driven     *
  *                      bean to connect to a particular         *
  *                      messaging engine, in order to prevent   *
  *                      messages from becoming stranded.        *
  ****************************************************************
  * RECOMMENDATION: WebSphere Application Server V6.1 provides   *
  *                 this functionality, and customers who        *
  *                 are able to do so are recommended to         *
  *                 migrate to the latest version.               *
  *                                                              *
  *                 However, some customers may be unable to     *
  *                 migrate due to version prerequisites of      *
  *                 other IBM software, such as WebSphere        *
  *                 Process Server V6.0.                         *
  *                                                              *
  *                 In other cases, it is possible to change     *
  *                 the topology design to remove the            *
  *                 requirement for this functionality.          *
  *                 In many cases, deploying the message driven  *
  *                 bean to the same application server (or      *
  *                 cluster) as the messaging engine which       *
  *                 hosts that destination is the best           *
  *                 solution.                                    *
  *                 This approach can have performance benefits  *
  *                 as well as protecting against stranded       *
  *                 messages.                                    *
  ****************************************************************
  When a message driven bean establishes an endpoint to a JMS
  destination, it makes a choice of which messaging engine to
  connect to - based on the information in the activation
  specification.
  
  If there is a messaging engine (for the bus specified in the
  activation specification) running in the local application
  server, the bean will connect to that messaging engine.
  Otherwise, the default behaviour is to connect to any messaging
  engine for the bus which is currently available.
  
  An example of where this default behaviour may not be
  sufficient, is when the destination is partitioned between
  multiple messaging engines in the bus for workload management.
  In this case, a user may need to deploy the message driven bean
  multiple times - to process messages from the individual
  partitions of the destination.
  
  In WebSphere Application Server V6.1 it is possible to do this
  using the "Target", "Target type" and "Target significance"
  properties when defining the JMS activation specification.
  
  In WebSphere Application Server V6.0 there was no mechanism to
  available to do this. This means that in some topologies it is
  not possible to prevent messages from being stranded.
  

Problem conclusion

• This WebSphere Application Server V6.0 APAR provides similar
  functionality to that available in WebSphere Application Server
  V6.1 - allowing a user to influence which messaging engine a
  message driven bean connects to.
  
  This functionality only affects the case where no messaging
  engine for the bus is running within the application server
  hosting the bean.
  
  In order to enable this functionality, a new profile must be
  created after applying this APAR.
  
  Once a new profile has been created with this APAR applied,
  three new "J2C activation specification custom properties" will
  be available for all activation specifications created.
  
  To view and edit these in the administration console:
  - Select "Resources"
  - Select "Resource Adapters"
  - Choose the scope at which the activation specification
    was defined.
  - Select "SIB JMS Resource Adapter"
  - Select "J2C Activation specifications"
  - Choose the activation specification from the list
  - Select "J2C activation specification custom properties"
  
  The three new properties are as follows:
  "target" - The target name
  "targetType" - Qualifies the target, and can have three values:
  
   1) "BusMember" if the target is the name of an application
      server, or cluster, which hosts a messaging engine within
      the bus.
   2) "ME" if the target is a messaging engine name.
   3) "Custom" if the target is the name of a custom group of
      messaging engines.
  "targetSignificance" - Whether the activation spec can connect
   to a messaging engine which does not match the target.
   Can have two values:
   1) "Preferred" - connection to any messaging engine is possible
  
   2) "Required" - connect only to a matching messaging engine
  
  More information about how these properties are used when
  establishing a connection to the bus is available in the
  following information center topic:
  http://publib.boulder.ibm.com/infocenter/wasinfo/v6r0/topic/
                com.ibm.websphere.pmc.doc/concepts/cjb0001_.html
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  PLAT MSG COM

• Fixed component ID

  620400101

Applicable component levels

• R100 PSY

     UP