MQ 5.3 and WLS 8.1

Question

          I want to use MQ 5.3 from WLS 8.1 MDBs. Seems like I can
          a) configure MQ as a foreign jms service, or
          b) use a JMS bridge.
          Is there a difference? From the documentation it seems as though the bridge offers
          superior transactional semantics. If I use a bridge do I configure MQ to register
          objects in some other local file or LDAP JNDI repository, then bridge from that
          JNDI to WLS JNDI?
          I'm confused about this whole thing, so I apologize if my question doesn't make
          sense. Does anyone have an explicit example they can share?
          Thanks,
          Jay
          

Answer 1

Hi Jay,
          - Unless your intent is to allow MDBs to continue
          processing backlogged messages while MQ is
          off-line, there is usually little reason
          to use a bridge. A bridge
          introduces an extra hop which increases latency and
          may decrease performance.
          - I assume you will also want to send from WL
          to MQ. If so, look into the new 8.1 resource
          reference wrapper feature as it helps simplify
          this task. You may want to bridge from
          a local dest to MQ instead,
          for the same reasons as one would bridge in
          the inbound direction - to allow message
          processing to continue even if MQ is down...
          - If you use the bridge there is no need to
          configure foreign destination or connection
          factory "wrappers", as you can specify
          the MQ URL, CF name, and dest name directly in
          the bridge configuration. Ditto for MDB
          descriptors. But foreign wrappers are nice for
          MDBs as then the MQ URL, CF name,
          and dest name no longer need to be hard-coded
          into the MDB and instead reside in the config.xml...
          - I'm attaching some notes I have on
          integration which contains some additional information.
          Tom
          jay philoon wrote:
          > I want to use MQ 5.3 from WLS 8.1 MDBs. Seems like I can
          > a) configure MQ as a foreign jms service, or
          > b) use a JMS bridge.
          >
          > Is there a difference? From the documentation it seems as though the bridge offers
          > superior transactional semantics. If I use a bridge do I configure MQ to register
          > objects in some other local file or LDAP JNDI repository, then bridge from that
          > JNDI to WLS JNDI?
          >
          > I'm confused about this whole thing, so I apologize if my question doesn't make
          > sense. Does anyone have an explicit example they can share?
          >
          > Thanks,
          > Jay
          Transactional Integration of Foreign JMS Vendors with BEA WebLogic Server
          The following notes are derived mostly from "http://dev2dev.bea.com/technologies/jms/index.jsp".
          For additional questions, a good forum for WebLogic questions in general is "newsgroups.bea.com". These can be mined for information by using Google's newsgroup search function.
          Feature Overview
          - For a foreign JMS vendor to participate in a WL transaction it must support XA. Specifically, it must support the javax.jms.XA* interfaces.
          - In WL versions 6.0 and up it is possible to make synchronous calls to foreign JMS vendors participate in a WL transaction as long as the foreign vendor supports XA.
          - WL 6.0 and 6.1 MDBs can be driven by foreign vendors non-transactionally. They can be driven transactionally by a select few foreign vendors (MQ is not part of the select few)
          - WL 7.0 and later, MDBs can be driven by foreign vendors transactionally and non-transationally.
          - WL 6.1 and later WL provides a messaging bridge feature. Messaging bridges forward messages between any two JMS destinations, including foreign destinations, and can transfer messages transactionally or non-transactionally.
          - WL 8.1 JMS provides additional features that simplify transactional and JNDI integration of foreign vendors. See http://edocs.bea.com/wls/docs81/jms/intro.html#jms_features
          Integration with 8.1 Details
          A good overview of 8.1 JMS interop capability is the presentation "Integrating Foreign JMS Providers with BEA WebLogic Server" here:
          http://www.bea.com/content/files/eworld/presentations/Wed_03_05_03/Application_Servers/1097-Foreign_JMS_Providers_WLS.pdf
          This document refers to helpful new 8.1 features, which simplify integration. These include:
          http://edocs.bea.com/wls/docs81/ConsoleHelp/jms_config.html#accessing_foreign_providers
          http://edocs.bea.com/wls/docs81/jms/j2ee_components.html#1033768
          And are also summarized here (under interoperability):
          http://edocs.bea.com/wls/docs81/jms/intro.html#jms_features
          The 8.1 features are likely sufficient for most 8.1 integration needs, and you may not need to refer "Using Foreign JMS Providers With WLS" white-paper mentioned below.
          Integration with 6.1 and 7.0 Details
          Read the "Using Foreign JMS Providers With WLS" white-paper:
          http://dev2dev.bea.com/products/wlserver/whitepapers/jmsproviders.jsp
          Note that this white-paper does not take into account 8.1 features.
          MQ Remote Capable XA Clients
          Until recently, IBM MQ JMS clients could not work transactionally unless they were running on the same host as their MQ server. This is a limitation unique to MQ that was relaxed with the introduction of IBM's new "WebSphere MQ Extended Transactional Client". See:
          http://publibfp.boulder.ibm.com/epubs/pdf/csqzar00.pdf
          The product is new, and for some reason, configuration of this client seems to be tricky, even when WebLogic is not involved at all. Oddly, the main sticking point seems to be simply making sure that class paths refer to the required IBM jars:
          - Required on WLS where MQ objects are bound into JNDI:
          com.ibm.mq.jar, com.ibm.mqjms.jar
          - Required only if MQ objects are bound into JNDI on a different server:
          com.ibm.mq.jar
          If there are problems when using this client, first get it to work using a pure IBM client without any BEA classes involved. Once that is working, search the WL JMS newsgroup for answers and/or contact BEA customer support.
          MDB Thread Pool Notes
          WL7.0SP? and WL8.1 and later support the "dispatch-policy" field to specify which thread pool an MDB uses to run its instances. In most cases this field should be configured to help address potential performance issues and/or dead-locks:
          http://edocs.bea.com/wls/docs81/ejb/DDreference-ejb-jar.html#dispatch-policy
          (Note that "dispatch-policy" is ignored for non-transactional foreign vendors; in this case, the MDB "onMessage" callback runs in the foreign vendor's thread.)
          MDB Concurrency Notes
          Queue MDBs driven by foreign providers can run multiple instances concurrently. Topic MDBs driven by foreign providers are limited to one instance (not sure, but transactional foreign driven topic MDBs may not have this limitation). The size of the thread pool that the MDB runs in and the "max-beans-in-free-pool" descriptor limit how many instances run concurrently.
          Performance Tuning Notes
          The "WebLogic JMS Performance Guide" white-paper contains detailed performance design and tuning information for the Messaging Bridge, JMS, and MDBs.
          http://dev2dev.bea.com/products/wlserver/whitepapers/WL_JMS_Perform_GD.jsp