CODEWITHSUNDEEP
ibm-mq
Bert
Bert

Reputation: 372

WebSphere MQ .NET client - Backout queue not working

I am not familiar with MQ so forgive me if I'm not explaining myself properly. We have received a message on a queue that is failing when being read with a 2110 MQRC_FORMAT_ERROR. It would seem that the problem is it doesn't have a 'Format' specified, e.g. we are expecting 'MQSTR'. The client code (C#) is catching the MQException and doing a MQQueueManager.Backout() however the message is just going back onto the queue and being read and rejected again by the client.

Looking at the queue I saw that it did not have a backout queue or backout threshold set. The queue manager also did not have a dead letter queue set. So what I've done is setup the DLQ and set the queue's backout queue to it with a backout threshold of 5. However the message is still stuck on the queue being continually read and put back. The backout count for the message is currently approaching 20 million.

I would like to get the backout and DLQ working but if there is another method to just manually delete or move this message that would help for now. It is just a test message so it doesn't matter if we lose it.

EDIT: I've had to clear the queue to get things moving so unfortunately might not be able to test any solutions until it happens again.

Upvotes: 0

Views: 1702

Answers (1)

Shashi
Shashi

Reputation: 15273

MQ native clients do not automatically move erroneous message to BackoutQ or DLQ. Application has to write additional code to move the messages to DLQ or Backout queue. However XMS .NET and JMS clients do this job. XMS .NET is a JMS specification implementation in C# language. XMS .NET comes bundled with MQ Clients package.

Coming to your case:

MQRC_FORMAT_ERROR is not actually an error, it's a warning telling the application that MQ client was not able to convert the incoming message and it delivered an unconverted message to the application. The application must handle this exception and should not rollback such messages. You will need to investigate the application that is sending such messages and fix any issues.

Please see the documentation here.

Upvotes: 6

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