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| PeterPotkay |
 Posted: Thu Dec 15, 2005 10:13 am Post subject: Dead Letter? |
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Poobah
Joined: 15 May 2001
Posts: 7722
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Why is it called a dead letter queue? What is this letter? Anyone know the history or reason behind this naming convention?
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Peter Potkay
Keep Calm and MQ On |
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| javagate |
| Posted: Thu Dec 15, 2005 10:17 am Post subject: |
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Disciple
Joined: 15 Nov 2004
Posts: 159
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Maybe DEAD.MESSAGE.QUEUE would have been better?
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WebSphere Application Server 7.0 z/OS &
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| jefflowrey |
| Posted: Thu Dec 15, 2005 10:18 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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You mean, where does the phrase "dead letter" come from?
Postal Service, of course.
There is a dead letter office, or several perhaps, for letters that can't be delivered due to bad addresses, or unknown recipients or etc.
The DLQ is a straight forward analogy for that office.
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Last edited by jefflowrey on Thu Dec 15, 2005 10:20 am; edited 1 time in total |
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| wschutz |
| Posted: Thu Dec 15, 2005 10:19 am Post subject: |
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Jedi Knight
Joined: 02 Jun 2005
Posts: 3316
Location: IBM (retired)
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Isn't DLQ easier to say the UDMQ (the un-deliverable message queue)?
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-wayne |
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| PeterPotkay |
| Posted: Thu Dec 15, 2005 11:53 am Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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| wschutz wrote: |
| Isn't DLQ easier to say the UDMQ (the un-deliverable message queue)? |
maybe. maybe not. But I am sure when IBM was naming this thing, they didn't say "UDMQ just doesn't roll of me tongue. Let's use DLQ, shall we?".
What's the real reason for "dead letter"? Or is Jeff's answer close?
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Peter Potkay
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| javagate |
| Posted: Thu Dec 15, 2005 12:05 pm Post subject: |
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Disciple
Joined: 15 Nov 2004
Posts: 159
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Jeff's answer makes sense. Thank's Jeff.
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WebSphere Application Server 7.0 z/OS &
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| fjb_saper |
| Posted: Thu Dec 15, 2005 12:32 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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Peter you might pick up on the analogy where in early stages messages had to be messenged over and came in letter format via messenger or snail mail.
So yes the DLQ got it's name from the Dead Letter Office.
Not withstanding the Dead Letter Office is quite busy.
Think about it: who writes back all the nice answers to the letters addressed to Santa, Krist Kindl, petit papa Noel, father Christmas, etc...
And if you are really curious try
Bad Santa
1, Brimstone Road
Hell, MI,
The city really exists but the rest is fictional and not even USPS will give the zip code for Hell, MI !!!
Happy Holidays.... HO HO HO...  |
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| wschutz |
| Posted: Sat Dec 17, 2005 3:53 am Post subject: |
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Jedi Knight
Joined: 02 Jun 2005
Posts: 3316
Location: IBM (retired)
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So Peter, have you gotten your answer? Or was your question: why did someone in IBM decided to name that queue "the dead letter queue"?
as an historical aside, the ezBridge MQ products had "two" dead letter queues (which were actually called INPUTDEFAULQUEUE and OUTPUTDEFAULTQUEUE), one for undeliverble outbound messages and one for undeliverable inbound messages. The doc refers to these as "dead letter queues" ....
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| hopsala |
| Posted: Sat Dec 17, 2005 5:53 pm Post subject: |
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Guardian
Joined: 24 Sep 2004
Posts: 960
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(congrats for breaking the 1000 post barrier wayne!)
Not only does jeff's answer stand to reason, but I found something to support it - in some of IBMs WMQ courses that I had delivered in the past, the way intercommunication is explained is through an explicit mailing metaphore and diagram; granted, the dlq remains unmentioned at that point in the course, but one gets the feeling that when MQ was first designed, they used the postal service in mind as a guiding concept... |
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| jsware |
| Posted: Mon Dec 19, 2005 4:28 am Post subject: |
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Chevalier
Joined: 17 May 2001
Posts: 455
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| hopsala wrote: |
| ...but one gets the feeling that when MQ was first designed, they used the postal service in mind as a guiding concept... |
And they sold it on assured delivery after using a postal service as a guiding concept 
See the following link http://www.press.uchicago.edu/Misc/Chicago/662764.html for details on Dead Letters.
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Regards
John
The pain of low quaility far outlasts the joy of low price. |
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| markt |
| Posted: Mon Dec 19, 2005 8:04 am Post subject: |
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Knight
Joined: 14 May 2002
Posts: 508
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| Quote: |
But I am sure when IBM was naming this thing, they didn't say "UDMQ just doesn't roll of me tongue. Let's use DLQ, shall we?".
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Well, that WAS pretty much the conversation... |
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