qpid-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Keith W <keith.w...@gmail.com>
Subject Re: [Java Client JMS] qpid-jms-client 0.22.0 vs qpid-client 6.1.2: prefetch behaving differently
Date Fri, 05 May 2017 09:07:44 GMT
Hi Dan

Thanks for the comprehensive report.  I can reproduce what you see and
confirm there appears to be a bug.  I'll hope to be able to take a
closer look later today or Monday and get back to you with more
information.

Keith.

On 4 May 2017 at 23:39, Dan Langford <danlangford@gmail.com> wrote:
> So over the past few weeks we have had a huge influx of messages on our
> enterprise message bus (qpid java 6.0.4 serves the AMQP1.0 messaging
> portion) and when one of our clients struggled scaling their application up
> it got us looking at prefetch. we thought it was odd that all 500k messages
> in the queue were prefetched and it was due to the prefetch that when they
> scaled out the new connections could help with those messages they could
> only acquire new messages.
>
> so i started running tests on a local instance of qpid java 6.1.2 and i was
> able to duplicate the behavior which seems odd.
>
> Setup.
> my java code will use the JMS api to create a consumer, receiveNoWait a
> message, acknowledge or commit the message, then Thread.sleep for a bit to
> look at the Qpid Java Brokers web interface for stats around prefetched
> messages.
>
> Test 1. qpid-jms-client 0.22.0 with prefetch of 10 set via jms url
> parameter (jms.prefetchPolicy.all=10) OR set via PreFetchPolicy on the
> ConnectionFactory (jmsDefaultPrefetchPolicy.setAll(10);)
> After the first message came in the web interface showed the queue size
> decrement and 19 messages pre-fetched
> after second message queue size decremented again and 28 messages are
> pre-fetched
> after third message queue size also decremented and 37 messages prefetched
> so on and so forth
>
> Test 2. qpid-client 6.1.2 with prefetch of 10 set via url param
> maxprefetch='10'
> After the first message came in the web interface showed the queue size
> decrement and 10 messages pre-fetched
> after second message queue size decremented again and still 10 messages are
> pre-fetched
> after third message queue size also decremented and still 10 messages
> prefetched
> so on and so forth
>
> could it be a link credit thing? could i not be understanding prefetch?
> maybe jms.prefetchPolicy is not the same as maxprefetch?
>
> Frame logs are here
> https://pastebin.com/4NHGCWEa

---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@qpid.apache.org
For additional commands, e-mail: users-help@qpid.apache.org


Mime
View raw message