Considerations for Commit mode 1 transactions

In IMS, commit mode 1 (CM1) transactions send their output replies before syncpoint.

A CM1 transaction might not be able to send its reply, for example because:

• The Tpipe on which the reply is to be sent is stopped

• OTMA is stopped

• The OTMA client (that is, the queue manager) has gone away

• The reply-to queue and dead-letter queue are unavailable

For all the above reasons, the IMS application sending the message pseudo-abends with code U0119. The IMS transaction and program are not stopped in this case.

These reasons often prevent messages being sent into IMS, as well as replies being delivered from IMS. A U0119 abend can occur if:

• The Tpipe, OTMA, or the queue manager is stopped while the message is in IMS

• IMS replies on a different Tpipe to the incoming message, and that Tpipe is stopped

• IMS replies to a different OTMA client, and that client is unavailable.

Whenever a U0119 abend occurs, both the incoming message to IMS and the reply messages to WebSphere MQ are lost. If the output of a CM0 transaction cannot be delivered for any of the above reasons, it is queued on the Tpipe within IMS.