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From Rob Lugt <robert.l...@cheynecapital.com>
Subject Re: Topic consumer appears throttled
Date Fri, 22 Sep 2006 22:08:26 GMT

Quick update to my earlier message.  I did eventually find the overload on
IConnection.CreateSession() to pass an AcknowledgementMode.  I tried setting
this to either AutoAcknowledge or DupsOkAcknowledge, but neither had an
affect on the apparent throttling of the consumer.

~Rob


Rob Lugt wrote:
> 
> Hi James, thanks for the quick reply.
> 
> Yes, I'm using NMS and C# for the client.  I wasn't specifying any
> particular acknowledgement mode, so my previous tests would have been
> using the default - but your question prompted me to try a few things out.
> 
> I found this article which describes acknowledgement modes for consumers:
> http://www.activemq.org/site/activemq-performance-module-users-manual.html
> 
> I couldn't find a way to directly manipulate the consumer acknowledgement
> mode using the NMS classes (if there is a way please tell me), so I used
> the URI syntax on the GetTopic() method e.g. 
> 
>   IDestination destination =
> session.GetTopic("PROD.PRICES.LIVE.IBM_LN?consumer.sessAckMode=autoAck");
> 
> Sorry, I don't know if I've got the syntax right, but it didn't make any
> difference to the tests.  I also tried the value "dupsAck" because I read
> somewhere that this could improve performance but it also didn't have any
> affect.
> 
> The listener is async (delegate added to consumer.Listener) - and is very
> light-weight.  I checked the CPU and memory activity on the client and the
> server and both were comfortably under utilised.
> 
> Best regards
> Rob Lugt
> 
> 
> James.Strachan wrote:
>> 
>> This sounds like it could be related to acknowledgements - you're
>> using NMS and C# as the client right? What acknowledgement mode are
>> you using and are you using the async or sync listener?
>> 
>> On 9/22/06, Rob Lugt <robert.lugt@cheynecapital.com> wrote:
>>>
>>> Hi
>>>
>>> I'm hoping to use AMQ for a stock price publishing system, so high
>>> throughput and low latency are important factors.  To verify that the
>>> kind
>>> of throughput we are after is achievable I've created a very simple
>>> producer/consumer pair based on the sample code in
>>> http://www.activemq.org/site/nms.html.
>>>
>>> I've come across a potential problem where the consumer's receive rate
>>> dramatically falls after the number of enqueued messages exceeds a
>>> certain
>>> threshold.  I'm pretty sure I must be falling foul of a configuration
>>> problem because the number 1000 seems to be significant.
>>>
>>> If the publisher sends 1000 messages, the consumer happilly receives
>>> them in
>>> a couple fo seconds. But, if I configure the publisher to send 1500
>>> messages
>>> in quick succession, I see a perculiar pattern: the consumer receives
>>> the
>>> first 300 messages quickly, it then receives the next 200 messages very
>>> slowly (approx 5 msgs/s) until there are exactly 1000 messages left in
>>> the
>>> queue and then it speeds through the last 1000 in just 2 seconds. If I
>>> increase the number of messages sent, the same pattern remains i.e. the
>>> consumer runs slowly until only 1000 messages remain then speeds up!
>>>
>>> Topology:
>>>   Client 1 and Client 2 both running on a single workstation, connecting
>>> via
>>> OpenWire using NMS
>>>   AMQ 4.0.1 Broker running on separate machine (Windows 2003 Server,
>>> J2SE
>>> 1.5.0_06)
>>>
>>> Client 1 opens a session and publishes n (non-persistent) messages to a
>>> single topic.
>>> Client 2 opens a session and registers a listener on the same topic.
>>>
>>> I've tried various options to overcome this, none of which seem to have
>>> had
>>> any impact.
>>> On connection uri I have:
>>> jms.useAsyncSend=true&consumer.dispatchAsync=false
>>> On Topic name I have: jms.useAsyncSend=true&consumer.dispatchAsync=false
>>>
>>> Any ideas/solutions gratefully received.
>>>
>>> Best regards
>>> Rob Lugt
>>>
>>>
>>>
>>> --
>>> View this message in context:
>>> http://www.nabble.com/Topic-consumer-appears-throttled-tf2318926.html#a6451007
>>> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>>>
>>>
>> 
>> 
>> -- 
>> 
>> James
>> -------
>> http://radio.weblogs.com/0112098/
>> 
>> 
> 
> 

-- 
View this message in context: http://www.nabble.com/Topic-consumer-appears-throttled-tf2318926.html#a6455875
Sent from the ActiveMQ - User mailing list archive at Nabble.com.


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