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Running channels as processes or threads

 

WebSphere MQ for Windows provides the flexibility to run sender channels as Windows processes or Windows threads. This is specified in the MCATYPE parameter on the sender channel definition. Each installation should select the type appropriate for their application and configuration. Factors affecting this choice are discussed below.

Most installations will select to run their sender channels as threads, because the virtual and real memory required to support a large number of concurrent channel connections will be reduced. When the WebSphere MQ listener process (started via the RUNMQLSR command) exhausts the available private memory needed, an additional listener process will need to be started to support more channel connections. When each channel runs as a process, additional processes are automatically started, avoiding the out-of-memory condition.

If all channels are run as threads under one WebSphere MQ listener, a failure of the listener for any reason will cause all channel connections to be temporarily lost. This can be prevented by balancing the threaded channel connections across two or more listener processes, thus enabling other connections to keep running. If each sender channel is run as a separate process, the failure of the listener for that process will affect only that specific channel connection.

A NetBIOS connection needs a separate process for the Message Channel Agent. Therefore, before we can issue a START CHANNEL command, start the channel initiator, or you may start a channel using the RUNMQCHL command.

 

Parent topic:

WebSphere MQ for Windows configuration

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