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| sebastia |
 Posted: Tue Oct 24, 2006 5:28 am Post subject: who writes in to Dead Letter Queue ? |
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Grand Master
Joined: 07 Oct 2004
Posts: 1003
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If I use AMQSPUT (or similar)
and a Local queue manager,
the messages with
*) too large size
*) destination queue name problems
*) destination queue with "disabled" PUT
do NOT go into the Dead Letter Queue
but the call just ends with a RC and CC.
Does it mean only the MCA of the receiver side of a channel
does write/put messages into the DLQ ?
Thanks. |
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| Vitor |
| Posted: Tue Oct 24, 2006 5:37 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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The DLQ is for messages which (for whatever reason) can't be delivered to their final destination queue. Hence only messages which have been accepted for delivery (i.e. put successfully) will go there.
I don't think it's only the receiver MCA that does this. Consider the situation where a sender MCA is unable to process a message, either because message size exceeds the channel limit or a channel conversion can't be honoured. In these cases the message will end up on the sender DLQ.
Likewise with a multihop. If there's no remote queue to the final destination (broken chain for example) it will end up on a DLQ before the break. I'd doubt the receiver MCA does that.
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| Vitor |
| Posted: Tue Oct 24, 2006 5:42 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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P.S. I have seen it done where an application program, on a failing put, wrote the failed message to a DLQ having first hand rolled a DLQ header onto the message. I viewed this with some suspicion and remain mostly unconvinced of the wisdom, but it was to "a" DLQ not "the" DLQ i.e. the one the queue manager was using. The principle was that the standard dead letter handler was used to process the messages using rules.
It seemed to work, given that the errors that ended up there were mostly 2053. I invite comments from the assembled wisdom. 
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| sebastia |
| Posted: Tue Oct 24, 2006 6:49 am Post subject: |
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Grand Master
Joined: 07 Oct 2004
Posts: 1003
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Thanks, Vitor
You have clever words also - they were
"ACCEPTED (MESSAGE) FOR DELIVERY" ....
( at least for me ....  )
Keep it up ! |
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| Vitor |
| Posted: Tue Oct 24, 2006 7:27 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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You're quite welcome! 
I'll just mention for the record and the benefit of future searchers that of course a non-persistant message that has been accepted for delivery does not necessarially end up anywhere.....
_________________
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Insanity is the best defence. |
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| jeevan |
| Posted: Wed Oct 25, 2006 5:55 am Post subject: |
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Grand Master
Joined: 12 Nov 2005
Posts: 1432
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Vitor wrote
| Quote: |
I'll just mention for the record and the benefit of future searchers that of course a non-persistant message that has been accepted for delivery does not necessarially end up anywhere.....
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What do you mean by 'doe not necessarily end up anywhere ' ? Does it mean they do in some occassion and do not in another occassions? Or they are never delivered to DLQ?
thanks |
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| jefflowrey |
| Posted: Wed Oct 25, 2006 5:59 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Non-persistant messages can get thrown away completely at a number of points, including when they could not be delivered over a channel.
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| Vitor |
| Posted: Wed Oct 25, 2006 6:03 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| jeevan wrote: |
What do you mean by 'doe not necessarily end up anywhere ' ? Does it mean they do in some occassion and do not in another occassions? Or they are never delivered to DLQ?
thanks |
I meant that under certain circumstances an undeliverable non-persistent message can be lost in a way that an undeliverable persistent message cannot be.
Think about it.
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