MQ TrigType, First or Every? 1

[el91]

Currently, I am having a problem with the TrigType setup...
The following is a scenario:
Before the CICS region is up, 6 messages, A, B, C, D, E, F, entered the queue. Because the region is not yet up, these messages could not trigger any transaction to retrieve them and eventually front end times out; hence, they are the residual messages. Now the CICS region is up, a new message G comes along and triggers a transaction to retrieve a message from the queue. However, the relating program of the transaction retrieves message A, processes it and exits, when in fact it should have processed message G instead. That's how residual message can cause problems.

Is there any way to avoid these residual messages?
Is it possible to get rid of those residual messages?
Would the setting First or Every do anything to handle that??

Please help. Many thanks in advance.

eric

 

[kevinf2349]

Well for quick and dirty you could just clear the queue immediately before CICS startup using CSQUTIL.

Ideally though you need to expire the messages (or have your application disgard them). Why not simply have an expiry time set to the same as the front-end timeout value?

 

[el91]

Thanks but using CSQUTIL is a bit risky as we may not notice a lost message.

We thought of using the Expiry in MQMD and the Report Message as well.

However, what is the extact difference between the FIRST and EVERY in the TRIGTYPE?

Thanks for any info.

 

[kevinf2349]

trigger type FIRST means when the depth goes from 0 to 1.

Trigger type EVERY means every time a message is written to the queue.

One warning with trigger type of FIRST is that in order for the trigger event to happen the queue must not be open for INPUT anywhere.