Using message sequences

Information about the state of in-flight messages is held on storage queues that are controlled by WebSphere MQ, so you must install it on the same computer as your integration node if you want to use the capabilities provided by the Sequence and Resequence nodes. The storage queues that hold the state information are owned by the queue manager that is associated with the integration node, and you specify this queue manager by using the -q property of the mqsicreatebroker command. For more information about specifying a queue manager, see Creating an integration node and mqsicreatebroker command.

If the integration node has the necessary permissions to create system queues, they are created automatically when a flow containing Sequence or Resequence nodes is deployed. If the queues are not created automatically, you can create them manually; see Creating the default IBM Integration Bus queues on a WebSphere MQ queue manager. For more information about the queues that are used to store events for message sequences, see Configuring the storage of events for Resequence nodes.

For more information about using WebSphere MQ with IBM Integration Bus, see Installing WebSphere MQ and Enhanced flexibility in interactions with WebSphere MQ.

The following topics describe the tasks involved in configuring message sequences:

• Adding sequence numbers to messages
• Reordering messages in a message flow
• Maintaining the sequential order of messages
• Handling missing messages
• Configuring the storage of events for Resequence nodes

The following topics provide examples of how to use a Resequence node, and show how the node processes messages in a message flow:

• Message sequencing scenario 1
• Message sequencing scenario 2