Hello,
Thank you Ganesh for your answer.
To answer your first question yes the consumers we have, issue one credit
per call.
For the the second question, yes we are attaching consumers before sending
the messages.
After setting the dispatch "link capacity" on the listeners to 1, we
managed to have an equal load-balancing of the messages between consumer 1
and 2.
Our understanding is that the problem comes from the prefetch at the level
of the "normal" listener, which is preventing the "inter-router" listener
to pass messages to the second dispatch.
You can find attached the new config files.
Is this the correct way to resolve this kind of problem? Does it sound
reasonable to you?
Best regards,
Rabih and Ali
On Thu, Jul 11, 2019 at 5:50 PM Ganesh Murthy <[email protected]> wrote:
>
>
> On Thu, Jul 11, 2019 at 10:37 AM Rabih M <[email protected]> wrote:
>
>> Hello,
>>
>> We are using Qpid dispatch router 1.7, Qpid broker 7.1.3 on redhat linux
>> rhel 6.4.
>>
>> Use case description:
>> We have a cluster of 2 dispatch routers and 2 brokers. A sharded queue
>> "myQueue" on the 2 brokers.
>> Here is an illustration:
>>
>> [image: Diagram.jpg]
>>
>> The producer produces 2 messages, the messages are load balanced on the 2
>> brokers. Then, Consumer 1 and consumer 2 ask for a receive().
>>
> Does your receive() function issue one credit per call?
>
>>
>> Our observation is that the consumer 1 consumes the first message and the
>> consumer 2 is never getting the second message.
>> We are aware that the first dispatch router will do a prefetch for the 2
>> messages but what is weird is that the prefetched message 2 is never routed
>> to the second dispatch router and consumer 2.
>> I attached the dispatch routers config.
>>
>> This is what is going on in my view -
> 1. The producer sends two messages - Message 1 goes to Broker 1 and
> Message 2 goes to Broker 2.
> 2. Now Consumer 1 attaches to Router 1 and calls receive() issuing one
> credit. (The Consumer 2 has not yet attached to Router 2). The autolinks
> from Broker 1 to Router 1 and Broker 2 to Router 2 each have a prefetch of
> 250 credits each. So,Message 1 and Message 2
> both come down to Router 1. Message 1 is sent to Consumer 1. Message 2 is
> waiting on the outbound queue of Consumer 1 waiting to receive a credit
> from Consumer 1.
> 3. Now Consumer 2 shows up and wants to receive Message 2 but that message
> is already queued up to go to Consumer 1 who is still keeping his
> connection open
> 4. If now Consumer 1 drops out, the Message 2 will be RELEASED back to its
> broker and that message will be sent to Consumer 2.
>
> Have you tried attaching Consumer 1 and Consumer 2 first and then
> subsequently bringing up the Producer 1 and send two messages ? In that
> case, I think, both consumers will receive one message.
>
> Thanks.
>
>> Do you have any idea how we can make consumer 2 receive the message?
>>
>> Thanks for your help,
>> Rabih
>>
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router {
mode: interior
id: ${dispatch.router.name}
workerThreads: 4
defaultDistribution: unavailable
}
listener {
name: normal_listener
host: 0.0.0.0
port: 0
role: normal
saslMechanisms: ANONYMOUS
requireSsl: no
authenticatePeer: no
linkCapacity: 1
}
listener {
name: inter_router_listener
host: 0.0.0.0
port: 0
role: inter-router
saslMechanisms: ANONYMOUS
requireSsl: no
authenticatePeer: no
linkCapacity: 1
}
log {
module: DEFAULT
enable: info+
includeSource: false
outputFile: stdout
}
connector {
name: broker1
role: route-container
host: 127.0.0.1
port: ${broker1.amqp.port}
}
connector {
name: broker2
role: route-container
host: 127.0.0.1
port: ${broker2.amqp.port}
}
address {
prefix: myQueue
waypoint: yes
}
autoLink {
name: consume_myQueue_broker1
addr: myQueue
connection: broker1
direction: in
}
address {
prefix: myTopic
waypoint: yes
}
autoLink {
name: produce_myTopic_broker1
addr: myTopic
connection: broker1
direction: out
}
autoLink {
name: consume_myQueue_broker2
addr: myQueue
connection: broker2
direction: in
}
autoLink {
name: produce_myTopic_broker2
addr: myTopic
connection: broker2
direction: out
}
router {
mode: interior
id: ${dispatch.router.name}
workerThreads: 4
defaultDistribution: unavailable
}
listener {
name: normal_listener
host: 0.0.0.0
port: 0
role: normal
saslMechanisms: ANONYMOUS
requireSsl: no
authenticatePeer: no
linkCapacity: 1
}
listener {
name: inter_router_listener
host: 0.0.0.0
port: 0
role: inter-router
saslMechanisms: ANONYMOUS
requireSsl: no
authenticatePeer: no
linkCapacity: 1
}
log {
module: DEFAULT
enable: info+
includeSource: false
outputFile: stdout
}
connector {
name: dispatch1
role: inter-router
host: 127.0.0.1
port: ${dispatch1.inter.router.port}
}
connector {
name: broker1
role: route-container
host: 127.0.0.1
port: ${broker1.amqp.port}
}
connector {
name: broker2
role: route-container
host: 127.0.0.1
port: ${broker2.amqp.port}
}
address {
prefix: myQueue
waypoint: yes
}
autoLink {
name: consume_myQueue_broker1
addr: myQueue
connection: broker1
direction: in
}
address {
prefix: myTopic
waypoint: yes
}
autoLink {
name: produce_myTopic_broker1
addr: myTopic
connection: broker1
direction: out
}
autoLink {
name: consume_myQueue_broker2
addr: myQueue
connection: broker2
direction: in
}
autoLink {
name: produce_myTopic_broker2
addr: myTopic
connection: broker2
direction: out
}
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