Hi again,
if it turns out to be a consumer, you could use the concept of a
Virtual topics to have several groups of consumers,
each group getting a message copy, but the group members sharing the
load.
To your question, You need to decide on a strategy what you do in case
of slow consumers. I think you are experiencing
the default - flow control. See Rob's suggestion as well. Besides you
*could* configure the broker in a way that the send throws an exception
if the situation occurs, but then that exception must be handled on
the producer site.
Best regards
Andreas
On Sep 2, 2009, at 2:36 PM, Rob Davies wrote:
Hi Tanel,
It would be worth disabling flow control - e.g.
disable flow control by setting the producerFlowControl flag to
false on a destination policy in the Broker configuration - e.g.
<destinationPolicy>
<policyMap>
<policyEntries>
<policyEntry topic="FOO.>" producerFlowControl="false"
memoryLimit="1mb">
<dispatchPolicy>
<strictOrderDispatchPolicy/>
</dispatchPolicy>
<subscriptionRecoveryPolicy>
<lastImageSubscriptionRecoveryPolicy/>
</subscriptionRecoveryPolicy>
</policyEntry>
</policyEntries>
</policyMap>
</destinationPolicy>
On 2 Sep 2009, at 12:35, wo wrote:
Hi.
We have 1 producer app and 2 consumers in total. Messages are
distributed
evenly between 2 separate topics.
Slow consumer should not be a problem, both consumers use
java.util.concurrent Executors working off an unbounded queue to
process the
incoming messages and every attempt has been made to make jms message
handoff to executors as fast as possible.
Messages itself are small, maybe 100 bytes of data in each. Our
topic memory
limit in activemq config is set to 20mb which seems sensible
enough. Would
it help to increase it further?
I'll try to confirm whether the consumer is to blame but even if it
was, is
there any workaround besides not putting a load on the system? :)
I'd say
its a pretty major issue with activemq, one slow consumer shouldn't
be able
to bring the whole thing down.
Regards,
Tanel
Andreas Gies wrote:
Hi there,
I am wondering how many consumers there are on the topic and if
there
are any slow consumers that
can't keep up with the messaging load. Without having verified it,
it
seems that your app hangs in the
the send message waiting for the response from the broker. That
would
happen, if the sending application
can't place the message in the broker.
One thing strikes me odd....if all of your consumers keep consuming,
that shouldn't happen. So it might
be a starting point to double check them.
As for the Advisory messages: Yes, thats normal. For more details on
advisories see
http://activemq.apache.org/advisory-message.html. You *could turn
advisories off,
but you need to remember to reenable them if you are switching to a
network of brokers
some day ;)
Hope that helps a bit
Andreas
On Sep 2, 2009, at 7:24 AM, wo wrote:
Hi.
We're having a problem under moderate to heavy load (~2500
nonpersisted
messages /second on a single broker) while producers will just hang
indefinitely at some point and producer application needs to be
restarted in
order to continue.
Here's a snippet from a producer application thread dump after
hang:
at
java
.util.concurrent.ArrayBlockingQueue.take(ArrayBlockingQueue.java:
317)
at
org
.apache
.activemq.transport.FutureResponse.getResult(FutureResponse.java:
40)
at
org
.apache
.activemq
.transport.ResponseCorrelator.request(ResponseCorrelator.java:80)
at
org
.apache
.activemq
.ActiveMQConnection.syncSendPacket(ActiveMQConnection.java:
1195)
at
org.apache.activemq.ActiveMQSession.send(ActiveMQSession.java:1644)
- locked <0x00002aaab5abeb30> (a java.lang.Object)
at
org
.apache
.activemq
.ActiveMQMessageProducer.send(ActiveMQMessageProducer.java:
227)
at
org
.apache
.activemq
.ActiveMQMessageProducerSupport
.send(ActiveMQMessageProducerSupport.java:241)
at
org.springframework.jms.core.JmsTemplate.doSend(JmsTemplate.java:
597)
So far we've tried upgrading AMQ from 5.1 to 5.2 and increasing the
memory
limits in broker config, both giving no result, the problem still
exists.
Neither application nor activemq log displays any errors /
exceptions.
One thing i have noticed is that for every message sent to a topic,
there
are 2 advisory messages being produced in
ActiveMQ.Advisory.Producer.Topic.TOPICNAME which strikes me as odd
but i
haven't been able to find any information in forums or manual about
whether
this is normal behaviour?
Producer side is a standalone Spring application with AMQ
connectionfactory
wrapped in spring SingleConnectionFactory and used in jmstemplate,
as per
example.
Any insight would be greatly appreciated.
Tanel Unt
Core Developer
Tracking Center Ltd.
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Rob Davies
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