Using message sequences
You can maintain or change the sequence of messages in a message flow based on the sequence number and group ID contained in each message.
Before you begin
- Read the following concept topics, which contain information that you need to understand before you can use message sequences:
- If you are using message sequencing on an integration server that is managed by an
integration node, ensure that you have installed IBM® MQ. Information
about the state of in-flight messages is held on storage queues that are controlled by IBM MQ, and you must install IBM MQ on the same computer as your integration node if you want to use the
capabilities provided by the Sequence and Resequence nodes. For more information about using IBM MQ with IBM App Connect Enterprise, see Installing IBM MQ.
If you are using message sequencing on an independent integration server, you can use a remote default queue manager to control the system queues, without the need to install IBM MQ on the same machine as the integration server. Interactions between an independent integration server and IBM MQ can use a client connection to a remote queue manager, by using a default policy setting. For information about using a remote default queue manager, see Using a remote default queue manager and Configuring an integration server to use a remote default queue manager.
About this task
Information about the state of in-flight messages is held on system queues that are controlled by IBM MQ, and these queues are owned by the queue manager that is specified on the integration server. You create these system queues by running the iib_createqueues command, as described in Creating the default system queues on an IBM MQ queue manager.
You associate a queue manager with the integration server by specifying the queue manager name on the defaultQueueManager property in the server.conf.yaml configuration file; for more information, see Configuring an integration server by modifying the server.conf.yaml file.
For more information about using IBM MQ with IBM App Connect Enterprise, see Installing IBM 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: