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Limiting the size of a message

The maximum message length (MaxMsgLength) attribute of a queue manager is the maximum length of a message that can be handled by that queue manager. The default maximum message length supported depends on the platform you are using.

On WebSphere MQ products, we can increase the maximum message length attribute of a queue manager. Details are given in the WebSphere MQ Application Programming Guide.

We can find out the value of MaxMsgLength for a queue manager by using the MQINQ call.

If the MaxMsgLength attribute is changed, no check is made that there are not already queues, and even messages, with a length greater than the new value. After a change to this attribute, applications and channels should be restarted in order to ensure that the change has taken effect. It will then not be possible for any new messages to be generated that exceed either the queue manager's MaxMsgLength or the queue's MaxMsgLength (unless queue manager segmentation is allowed).

The maximum message length in a channel definition limits the size of a message that we can transmit along a client connection. If a WebSphere MQ application tries to use the MQPUT call or the MQGET call with a message larger than this, an error code is returned to the application.

 

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