This example demonstrates that only one MQInput node at a time is allowed to take messages from a shared queue when the same serialization token is used by message flows running in separate execution groups on the same broker.
An identical message flow MyFlowA is deployed to two execution groups called MYGroupA and MYGroupB on broker MQ01BRK.
In this case it is not a requirement that the queue manager participates in a queue sharing group. The input queue INQueue is defined as local with disposition QMGR.
BIP2656I MQ01BRK MyGroupB 11 UNABLE TO OPEN QUEUE 'INQueue' ON WEBSPHERE BUSINESS INTEGRATION QUEUE MANAGER 'MQ01': BECAUSE SERIALIZATION TOKEN MyToken123ABC is already in use. NO USER ACTION REQUIRED
Message flow MyFlowA in execution group MyGroupB is unable to process input because the serialization token it has passed is already in use within the queue manager (by the MQInput node in message flow MyFlowA in execution group MyGroupA). This is indicated by the reason code 2271 (MQRC_CONN_TAG_IN_USE) in message bip2623.
If the first execution group is cancelled by the operator, abends, or is deleted during a redeployment of the broker configuration, then the input node in the second execution group is now able to get input messages from queue INQueue.
BIP2091I MQ01BRK MyGroupB 11 THE BROKER HAS RECONNECTED TO WEBSPHERE BUSINESS INTEGRATION SUCCESSFULLY : ImbCommonInputNode(785)
Message flow MyFlowA in execution group MyGroupB is now able to recover processing of messages from the shared queue INQueue.QSG.
Note that, although serialization of input can be achieved in a similar manner by configuring the input queue for exclusive input, this does not ensure message integrity during a recovery situation. This can be achieved only through the use of the serialization token as described in this example.