| |
|
RSS Feed - WebSphere MQ Support
|
RSS Feed - Message Broker Support
|
  |
|
| delivery sequence |
« View previous topic :: View next topic » |
| Author |
Message
|
| gunter |
 Posted: Thu Nov 29, 2007 12:01 am Post subject: delivery sequence |
 |
|
Partisan
Joined: 21 Jan 2004
Posts: 307
Location: Germany, Frankfurt
|
Hi,
maybe this subject is discussed several times, but I couldn't find I was looking for because searching with keywords always results in thousends of hits with channel problems(out of sync, ...).
We deliver messages from one queue on the first queuemanager to one queue on the second.
- All messages are not persitence
- The channel uses fast delivery
- The channel is used for this messages only.
- Priority is default, all the same.
- MessageId and CorrelationId not used
- No Syncpoint
- Batchsize and Batchinterval are default.
- One process with one thread puts.
- One process with one thread gets.
Is it with this configuration possible that the receiving application gets messages not in the sequence they are putted (first in, first out)?
If yes, how to avoid this.
Thanks in Advance.
Regards Gunter
_________________
Gunter Jeschawitz
IBM Certified System Administrator - Websphere MQ, 5.3 |
|
| Back to top |
|
 |
| Vitor |
| Posted: Thu Nov 29, 2007 2:01 am Post subject: Re: delivery sequence |
|
|
Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
|
| gunter wrote: |
| Is it with this configuration possible that the receiving application gets messages not in the sequence they are putted (first in, first out)? |
With the configuration you've described it's unlikely but possible. What's more likely is that 6 weeks/6 months/6 years down the line something will change that will make it more likely. MQ doesn't guarantee message delivery sequence, which is why message affinity is considered such a bad thing.
| gunter wrote: |
If yes, how to avoid this.
|
I think most of the options available were discussed to death here:
http://www.mqseries.net/phpBB2/viewtopic.php?t=34227
_________________
Honesty is the best policy.
Insanity is the best defence.
Last edited by Vitor on Thu Nov 29, 2007 6:57 am; edited 1 time in total |
|
| Back to top |
|
|
| PeterPotkay |
| Posted: Thu Nov 29, 2007 6:34 am Post subject: Re: delivery sequence |
|
|
Poobah
Joined: 15 May 2001
Posts: 7722
|
| Vitor wrote: |
| MQ doesn't guarantee message delivery... |
I'm sure Vitor meant to say "doesn't guarentee message delivery sequence, unless a very specific set of circumstances are met."
_________________
Peter Potkay
Keep Calm and MQ On |
|
| Back to top |
|
|
| Vitor |
| Posted: Thu Nov 29, 2007 6:45 am Post subject: Re: delivery sequence |
|
|
Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
|
| PeterPotkay wrote: |
| Vitor wrote: |
| MQ doesn't guarantee message delivery... |
I'm sure Vitor meant to say "doesn't guarentee message delivery sequence, unless a very specific set of circumstances are met." |
DOH!!!!!!!!!!!!!!!!! 
doesn't even START to cover that!
DOH!
DOH!
I swear before the Great Blue God that it didn't say that in my head. I'm off to find a new set of fingers...... 
Oh  it. What a thing to say...... 
_________________
Honesty is the best policy.
Insanity is the best defence. |
|
| Back to top |
|
|
| bruce2359 |
| Posted: Thu Nov 29, 2007 7:44 am Post subject: |
|
|
Guest
|
| Quote: |
- All messages are not persitence
- The channel uses fast delivery |
Danger, Danger (Will Robinson)!
Non-persistent messages and NPMSPEED(FAST) channel setting pretty much guarantees that MQ will discard messages if they can't be delivered to the destination queue and dead letter queue - for any reason. Non-persistent messages will also be discarded if the qmgr restarts. If you are concerned with loss of messages, correct these.
If you are concerned only with maintaining message delivery sequence, look at message groups. |
|
| Back to top |
|
|
| gunter |
| Posted: Mon Dec 03, 2007 9:08 am Post subject: |
|
|
Partisan
Joined: 21 Jan 2004
Posts: 307
Location: Germany, Frankfurt
|
Hi,
Thanks for your response. I played around with this and couldn't reproduce this behavior in a test environment. After changing the channel form FAST to NORMAL we had no further problems. But the absence of the problem over a short time is no prove that the solution is found.
We have no problem wit loosing messages if a problem occures even not if the queuemanager dies. Th only problem is, loosing messages or get messages in a wrong order without any trace. To get the information if a message is thrown away by the MCA we use exception reports.
I don't know the real reason for this queue-jumping of a message. Maybe performance optimization for FAST channel on a multiprocessor machine is it. I would appreciate to know what happens to go on the safe side without reducing the throughput more than necessary.
| bruce2359 wrote: |
Quote:
- All messages are not persitence
- The channel uses fast delivery
Danger, Danger (Will Robinson)!
|
Sorry, but I don't agree. It has to fit in the whole system and sometimes persistent messages are not the right choice.
With this argumentation persistent messages are often used without having a real reason for it, p.e. in request-response scenarios or for state information.
If you ask why, the answer is:
We deliver all messages as safe as possible.
And if you ask "Who is interested in it after restarting the queuemanager?" the answer is: Nobody.
And fast delivery makes only sense with non persistent messages.
_________________
Gunter Jeschawitz
IBM Certified System Administrator - Websphere MQ, 5.3 |
|
| Back to top |
|
|
|
|
|
| |
|
Page 1 of 1 |
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
|
|
|
