(WMB) Publisher Subscriber in WMB 7.0

Publish/Subscribe architecture is useful in scenarios where P2P might not be suitable, reasons are obvious :

• Problems with large numbers of senders & receivers.
• Problems when senders & receivers change frequently; (Becomes unmanageable)

How it works in WMB 7.0

• MQ based subscription messages registered using a special queue SYSTEM.BROKER.CONTROL.QUEUE.
• Do not need to define a queue to handle subscription requests.
• Publication messages handled within the flow.
• Publication node receives publication messages and distributes to the subscribers matching the topic within the publication message.

Subscriber Flow

MQINPUT ->>  COMPUTE ->> MQOUTPUT (SYSTEM.BROKER.CONTROL.QUEUE)

Code for Compute Node :

                    CALL CopyEntireMessage();

                         SET OutputRoot.MQRFH2.psc.Command = 'RegSub'; --RegSub is a keyword

                         SET OutputRoot.MQRFH2.psc.Topic = 'SPORTS';  --TopicName

                         SET OutputRoot.MQRFH2.psc.QName = 'DATA';  -- QueueName

                         SET OutputRoot.MQRFH2.psc.QMgrName = 'QM';  -- QueueManagerName

                         Declare PTR REFERENCE to OutputRoot.MQRFH2;

                         Detach PTR;

                         attach PTR TO OutputRoot.MQMD AS NEXTSIBLING ;

 Publisher Flow

MQINPUT ->> COMPUTE ->> PUBLICATION NODE

Code for Compute Node :

                    CALL CopyEntireMessage();

                         SET OutputRoot.MQRFH2.psc.Command = 'Publish'; -- Publish is a keyword

                         SET OutputRoot.MQRFH2.psc.Topic = 'SPORTS'; --TopicName

                         Declare PTR REFERENCE to OutputRoot.MQRFH2;

                         Detach PTR;

                         attach PTR TO OutputRoot.MQMD AS NEXTSIBLING ;

                         RETURN TRUE;
OR

Exception Scenario :

While subscribing, we may get following warning :

And no subscription happens. I solved this issue by having the logged user name less then 12 chars, we can also see : http://www.mqseries.net/phpBB2/viewtopic.php?t=1056&highlight=2035+sid