Changing programs and transactions

In an IMS DB/DC or DCCTL environment, the online change PREPARE command stops all incoming messages and transactions for a resource to be changed, but does not affect messages that have already been queued.

The online change COMMIT command does not take effect until messages for a directly affected resource to be changed or deleted have been scheduled (dequeued), so you must either wait for the messages to be scheduled or stop the associated transactions.

If you do not want to wait for the messages to be scheduled (for the online change COMMIT command to take effect), use the /STOP or /PSTOP command to stop the associated transactions before issuing the online change COMMIT command.

Recommendation: Plan to make your changes when activity associated with the resource is low—when there are few transactions to be processed. When activity is low, you will not have to wait long for messages to be scheduled or have many transactions to stop if you do not want to wait.

You must stop all message-driven Fast Path programs and wait-for-input programs that refer to resources to be changed or deleted because the online change COMMIT command does not execute if any wait-for-input programs have been scheduled.

Also, any active conversations involving resources to be changed or deleted must complete before the online change COMMIT command can complete.