Stopping MQI channels

When we issue a STOP CHANNEL command against a server-connection channel, we can choose what method to use to stop the client-connection channel. This means that a client channel issuing an MQGET wait call can be controlled, and we can decide how and when to stop the channel.

Quiesce

Stops the channel after any current messages have been processed.

If sharing conversations is enabled, the IBM MQ MQI client becomes aware of the stop request in a timely manner; this time is dependent upon the speed of the network. The client application becomes aware of the stop request as a result of issuing a subsequent call to IBM MQ.

Force

Stops the channel immediately.

Terminate

Stops the channel immediately. If the channel is running as a process, it can terminate the channel's process, or if the channel is running as a thread, its thread.

This is a multi-stage process. If mode terminate is used, an attempt is made to stop the server-connection channel, first with mode quiesce, then with mode force, and if necessary with mode terminate. The client can receive different return codes during the different stages of termination. If the process or thread is terminated, the client receives a communication error.

The return codes returned to the application vary according to the MQI call issued, and the STOP CHANNEL command issued. The client will receive either an MQRC_CONNECTION_QUIESCING or an MQRC_CONNECTION_BROKEN return code. If a client detects MQRC_CONNECTION_QUIESCING it should try to complete the current transaction and terminate. This is not possible with MQRC_CONNECTION_BROKEN. If the client does not complete the transaction and terminate fast enough it will get CONNECTION_BROKEN after a few seconds. A STOP CHANNEL command with MODE(FORCE) or MODE(TERMINATE) is more likely to result in a CONNECTION_BROKEN than with MODE(QUIESCE).

Related information

• Channels