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| kordi |
 Posted: Sun Oct 31, 2021 2:28 am Post subject: Best way to handle DLQ messages in production |
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Centurion
Joined: 28 May 2012
Posts: 146
Location: PL
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Hi guys,
I was wondering what is your best way to handle messages in DLQ. The first though would be DLQ handler but is it always good to automatically process these messages in production? Maybe 3rd party tool that monitors DLQ and sends a notification to admins/oncall person? Maybe a tool that sends email to the administrator + raising a ticket to the owner of the queue the message should end up in? Or maybe L1 team that looks at dashboards and contacts admins/doing some maintanance in case message arrived to DEADQ?
What tools and what rules are you using and why you do that that way? |
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| bruce2359 |
| Posted: Sun Oct 31, 2021 3:35 am Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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Search google for “IBM MQ DLQ purpose”. Much of what you’re asking is discussed in these posts.
Policies and procedures for dealing with messages in the DLQ should be developed and tested in DEV/TEST along with the apps that produce messages that may end up in a DLQ.
_________________
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ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| kordi |
| Posted: Sun Oct 31, 2021 3:49 am Post subject: |
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Centurion
Joined: 28 May 2012
Posts: 146
Location: PL
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| Thank you for valuable answer but I was asking about your thoughts as experienced MQ administrators on this topic. |
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| bruce2359 |
| Posted: Sun Oct 31, 2021 12:12 pm Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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I'm not being flippant when I say that It depends.
It depends on the QoS of the message type. Banking funds-transfer messages likely require a higher QofS than, say, HR or inventory inquiry messages.
Business requirements lead to SLA's (service level agreements) which drive the level of automation and out-call, as necessary.
Your pattern-matching rules should redirect DLQ messages to attempt processing in case the destination queue was unavailable for some transitory reason.
The last rule should move a DLQ message to a to-be-handled-manually queue so that the DLQ doesn't fill up, which, for persistent messages, will cause the channel to fail.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| kordi |
| Posted: Sun Oct 31, 2021 12:37 pm Post subject: |
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Centurion
Joined: 28 May 2012
Posts: 146
Location: PL
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Thanks for your answer.
I am trying to find the best way to handle messages. Imagine you have 100+ apps using MQ and you want to discuss details with each end every one.
Running DLQ handler is obvious but maybe there is a better tool to handle undelivered messages? I am curious what are you using at your work to deal with DLQ messages.
I was thinking about general rule like for example if q was full try to deliver 10 times every 5 minutes while all others goes to hoplesscases.ql
But some messages must be processed in a specific order or must come in specific groups and I am not sure if this is the best idea. |
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| bruce2359 |
| Posted: Sun Oct 31, 2021 3:13 pm Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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| kordi wrote: |
Thanks for your answer.
I am trying to find the best way to handle messages. Imagine you have 100+ apps using MQ and you want to discuss details with each end every one. |
I'm not sure what this means. "discuss details" with who? about what? Application design and testing must anticipate messages ending up in a down-network DLQ, and what should be done with them.
| kordi wrote: |
| Running DLQ handler is obvious but maybe there is a better tool to handle undelivered messages? I am curious what are you using at your work to deal with DLQ messages. |
The IBM-supplied and supported dead-letter handler utility works.
| kordi wrote: |
| I was thinking about general rule like for example if q was full try to deliver 10 times every 5 minutes while all others goes to hoplesscases.ql |
The IBM-supplied ... offers retry n times, and other options, that are explained in the URL's I offered previously.
| kordi wrote: |
| IBut some messages must be processed in a specific order or must come in specific groups and I am not sure if this is the best idea. |
Message groups and other message dependencies are application design choices. The IBM-supplied ... processes one message at a time.
IBM MQ does NOT process messages. Applications process messages.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| kordi |
| Posted: Mon Nov 01, 2021 1:19 am Post subject: |
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Centurion
Joined: 28 May 2012
Posts: 146
Location: PL
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| Quote: |
| I'm not sure what this means. "discuss details" with who? about what? Application design and testing must anticipate messages ending up in a down-network DLQ, and what should be done with them. |
With application owners, how do they see handling messages that went to DLQ
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| The IBM-supplied and supported dead-letter handler utility works. |
So you want to tell me you have never used/been working with any 3rd party tools that can monitor your MQ infrastructure, like Tivoli, contact admin, Patrol etc???
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The IBM-supplied ... offers retry n times, and other options, that are explained in the URL's I offered previously.
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I am 100% aware of capabilities of DLQ handler but thanks for reminder.
| Quote: |
| IBM MQ does NOT process messages. Applications process messages. |
Did I mention somewhere it doeas? |
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| bruce2359 |
| Posted: Mon Nov 01, 2021 2:52 am Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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The usual process here and other post sites is a conversation - for those responding to posts to solicit further clarifying information. I meant no offense.
FURTHER: Some of us here are paid professional SME’s. We cheerfully and voluntarily offer our services - up to a point. You’ve offered little about what you understand, have researched, or have tried, to answer your OP.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| kordi |
| Posted: Tue Nov 02, 2021 11:00 am Post subject: |
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Centurion
Joined: 28 May 2012
Posts: 146
Location: PL
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I am not sure how to interpret your answer. Did you say my answers were offensive? If yes I did not mean that. I am not an English native speaker and maybe I am missing something here...
I asked a question about your best practices with handling DLQ messages on a well known MQ forum. What tools and what approach are you using to this topic? Were you using a different approach in the past but found something that changed your mind?
I was hoping for answers describing your experience in this topic, for example: "from my experience the best tool is Moogsoft/contact admin/Geneos with this and this plugin" or "I've found nothing better than runmqdlq with a good rules table".
I am aware it depends and some applications may want to handle their messages this or that way but I bet you are using a 3rd party tools that help you with dealing with DLQ messages. |
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| bruce2359 |
| Posted: Tue Nov 02, 2021 11:36 am Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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| kordi wrote: |
| I asked a question about your best practices with handling DLQ messages on a well known MQ forum. What tools and what approach are you using to this topic? Were you using a different approach in the past but found something that changed your mind? |
I simply read this and your OP as your demand that us professionals do the multi-variant analytical work that you could/should do first, before you come to us with your more specific technical questions.
Like others here, I've spent decades as a solution provider - supporting MQ on a variety of hardware and o/s platforms, for large and small organizations, government and industry. Like others here, I earn a living doing what you are asking us to do for you for free.
I repeat my initial response: "It depends." My recommended practices depend on the client's specific business requirements.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| gbaddeley |
| Posted: Tue Nov 02, 2021 9:01 pm Post subject: |
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Jedi Knight
Joined: 25 Mar 2003
Posts: 2538
Location: Melbourne, Australia
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"runmqdlq with a good rules table" works for us. We have 100+ production queue managers and dozens of app systems using MQ messaging and MFT file transfers. We don't generally retry on queue full situations as all our queues are maxdepth for >24 hours of volume (for DR purposes). If there are no other common situations that can be handled by rules, move the message to a separate queue that alerts for queue depth > 0, and the support team will then decide what action is required. Your systems should be robust enough that is a rare occurence.
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Glenn |
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| bruce2359 |
| Posted: Wed Nov 03, 2021 7:00 am Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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| gbaddeley wrote: |
| "runmqdlq with a good rules table" works for us. We have 100+ production queue managers and dozens of app systems using MQ messaging and MFT file transfers. We don't generally retry on queue full situations as all our queues are maxdepth for >24 hours of volume (for DR purposes). If there are no other common situations that can be handled by rules, move the message to a separate queue that alerts for queue depth > 0, and the support team will then decide what action is required. Your systems should be robust enough that is a rare occurence. |
The OP title mentions ‘PRODUCTION.’ My recommended practice is to develop in TEST/DEV all of the environment that you will percolate to QA, then to PROD - including DLQ message handling.
My clients have used a variety of monitoring and automation tools. My favorite is the one that the client embraces.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| PeterPotkay |
| Posted: Wed Nov 03, 2021 1:53 pm Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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Cześć kordi
We use BMC's MVMM to monitor MQ. In that tool I have created policies that automatically assign a set of Event templates to any dead letter queue as soon as the tool discovers a new one (when we build a new queue manager). So all DLQs have the same set of alerts.
We create alerts based on the queue depth, start with emails only and flashing in the MVMM alert console up to Incident tickets of escalating severity.
I have never been a fan of dead letter handlers, but we are starting to do some work in this space.
DLQ messages that we normally just delete will be offloaded to another DLQ with a CAPEXPRY set so the messages go away on their own eventually but are there if we need to refer to them in the short term. Alerts will be built on this queue to let us know if there is an excessive amount of messages here.
Applications that are willing to deal with a Dead Letter Header in the reply messages will be set up with a rule in the dead letter handler that will automatically bounce back the message to their Reply To Queue versus going to the DLQ for certain reason codes.
At the end of the dead letter handler will be a catch all rule that sends to the really dead letter queue with the alerts mentioned above to get people to manually look at it.
I have not seen very many DLQ situations where there is value in automatically periodically retrying the messages because usually it requires human intervention to solve the root cause.
The new feature in MQ that allows you to put a max file size on queue is interesting to me for the DLQ because we have to allow a big max message size on the DLQ for the occasionally huge message but at the same time allow a big max q depth to allow for a flood of tiny messages. So we are at risk for the DLQ filling up disk space. Now we will be able to cap the max file size for the DLQ and just max out max depth and message length.
_________________
Peter Potkay
Keep Calm and MQ On |
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| gbaddeley |
| Posted: Wed Nov 03, 2021 3:31 pm Post subject: |
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Jedi Knight
Joined: 25 Mar 2003
Posts: 2538
Location: Melbourne, Australia
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| PeterPotkay wrote: |
...
The new feature in MQ that allows you to put a max file size on queue is interesting to me for the DLQ because we have to allow a big max message size on the DLQ for the occasionally huge message but at the same time allow a big max q depth to allow for a flood of tiny messages. So we are at risk for the DLQ filling up disk space. Now we will be able to cap the max file size for the DLQ and just max out max depth and message length. |
Our SDLQ is set to 100MB max msg length and default 999,999,999 max depth. We have acres of disk space and alerting for 80% full and 90% full. Running out of disk space is bad for MQ.
_________________
Glenn
Last edited by gbaddeley on Thu Nov 04, 2021 1:40 pm; edited 1 time in total |
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| PeterPotkay |
| Posted: Wed Nov 03, 2021 5:13 pm Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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| gbaddeley wrote: |
Our SLDQ is set to 100MB max msg length and default 999,999,999 max depth. We have acres of disk space and alerting for 80% full and 90% full. Running out of disk space is bad for MQ. |
Even a 1 byte message in the DLQ will be closer to 1 KB of disk space when you factor in the Dead Letter Header and MQMD Header.
999,999,999 x 1,024 = 1 terabyte
Unless you have 1+ TB of disk per QM (how much is an acre of storage  ) I think the QM will  long before you hit your >80% alert and that's assuming a best case of only 1 byte app messages and all other queues near empty.
_________________
Peter Potkay
Keep Calm and MQ On |
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