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| Sequencing problem with multiple instances of message flow |
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| Goeff |
 Posted: Tue Apr 17, 2007 8:13 pm Post subject: Sequencing problem with multiple instances of message flow |
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Newbie
Joined: 17 Apr 2007
Posts: 9
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Hi there. I got several questions about load balancing and message sequencing. It would be really really great if someone can help.
Here is my challange:
I have to handle messages from various clients (senders). However, it is expected that the amount of messages to be processed will be HUGE. More specifically, one of the senders will consume 1/3 of the traffic.
So, I decided to use multiple instances of a message flow to balance the work load.
And here are the questions:
1) As far as I understand, using multiple instances of a message flow can imporove the performance. However, having multiple instances of the same message flow will damage the sequencing of messages. Is there any way to get around the sequenced problem while having multiple instances of message flow to increase performance.
2) While I have multiple instances of message flow, lets say 5 instances, can I allowcate 2 of them to handle messages from a specific sender while the other 3 instances to handle messages from other senders?
Many thanks!
Danny |
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| marcin.kasinski |
| Posted: Tue Apr 17, 2007 11:24 pm Post subject: Re: Sequencing problem with multiple instances of message fl |
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Sentinel
Joined: 21 Dec 2004
Posts: 850
Location: Poland / Warsaw
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In my opinion
| fundanny wrote: |
1) As far as I understand, using multiple instances of a message flow can imporove the performance. However, having multiple instances of the same message flow will damage the sequencing of messages. Is there any way to get around the sequenced problem while having multiple instances of message flow to increase performance.
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No.
Tip: Analyze your architecture.
Do you really need sequence in all messages processes by this flow.
Very often people have message sequence requirements. Then after short discussion they realize that sequence is not necessary.
| fundanny wrote: |
2) While I have multiple instances of message flow, lets say 5 instances, can I allowcate 2 of them to handle messages from a specific sender while the other 3 instances to handle messages from other senders?
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No.
and again ... Analyze your architecture
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Marcin |
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| Goeff |
| Posted: Wed Apr 18, 2007 12:58 am Post subject: |
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Newbie
Joined: 17 Apr 2007
Posts: 9
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Thanks Marcin.
In my case, the sequence is vital.
According to you, Marcin, does it means that I can only have a single instance of a message flow in order to keep the sequence?
However, according to:
http://www-128.ibm.com/developerworks/websphere/library/techarticles/0311_dunn/dunn.html
Can I set the message broker to use "Queue order" to sequence messages, in order to have multiple instances of message flow?
Plase correct me if I am wrong in any ways.
Many thanks and have a nice day!
Danny |
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| Goeff |
| Posted: Wed Apr 18, 2007 1:12 am Post subject: |
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| jefflowrey |
| Posted: Wed Apr 18, 2007 3:35 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Is the sequence of the messages important within broker? or only outside of broker?
That is, do I need information from Msg A in order to process Msg B?
If not, you can consider a scheme that will allow you to store the msg sequence information, process messages in random order, and then restore the message sequence.
This will depend somewhat on how many messages the necessary sequence covers and how long a time span the sequence will cross.
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I am *not* the model of the modern major general. |
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| pcelari |
| Posted: Wed Apr 18, 2007 5:03 am Post subject: Re: Sequencing problem with multiple instances of message fl |
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Chevalier
Joined: 31 Mar 2006
Posts: 411
Location: New York
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| fundanny wrote: |
2) While I have multiple instances of message flow, lets say 5 instances, can I allowcate 2 of them to handle messages from a specific sender while the other 3 instances to handle messages from other senders?
Danny |
it seems to me what you really need is not the overall sequence, rather the sequence within individual clients - senders. Is this correct?
If that's the case, you can at least deploy the msgflow to different execution groups, each dedicated to a certain client, with dedicated inputQ, but without invoking multiple instances.
multiple instances will always distroy sequence.
_________________
pcelari
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- a master of always being a newbie |
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| Goeff |
| Posted: Wed Apr 18, 2007 8:41 pm Post subject: |
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Newbie
Joined: 17 Apr 2007
Posts: 9
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Thanks a lot Jeff and Pcelari.
Pacelari, you said "multiple instances will always distroy sequence". This is where I really get lost. According to an IBM article
"If you set Order Mode to By User ID, the node ensures that messages from a specific user (identified by the UserIdentifier field in the MQMD) are processed in guaranteed order. A second message from one user is not processed by an instance of the message flow if a previous message from this user is currently being processed by another instance of the message flow."
This seems to me that have the "Order Mode" set to "User ID" can allow me to have multiple instances of message flow (although I understand that each "User" can only consume 1 instance at a time).
Consider there are 10 users using the MQ, and there are 10 instances of message flow. All 10 users put messages to the MQ at the same time and it will be very likely that each user will be allocated with an instance of the message flow. While the sequence if the message for individual user can be preserved, but not amount the users. Am I correct?
The article can be found at: http://publib.boulder.ibm.com/infocenter/wmbhelp/v6r0m0/index.jsp?topic=/com.ibm.etools.mft.doc/ac00350_.htm |
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