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https://issues.apache.org/jira/browse/QPIDJMS-86?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Robbie Gemmell resolved QPIDJMS-86.
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Resolution: Not A Problem
Hi Alex,
In AMQP 1.0 the 'receiver' end of a link grants the 'sender' end of the link an
amount of credit to transfer messages, and it is the receivers responsibility
to replenish that credit as it gets used by the sender. As such, the available
'prefetch' for a given consumer is entirely controlled by the client, and it is
this value which the clients configuration allows you to configure.
I'm not sure where you see the broker reported prefetch, but the value is
presumably for the 'internal consumer' within the ActiveMQ brokers AMQP
protocol module, which itself has absolutely no control over how much link
credit the remote AMQP receiver grants (if it grants any).
There have been a number of improvements in the AMQP support for ActiveMQ 5.12
(which should hopefully be released in near term), particularly in the area of
credit handling, so I would suggest trying the current snapshots to see how it
works for you, if you havent already (I'm unclear from the report which version
you are using).
Robbie
> AMQP 1.0 prefetch policy set to 0 by the broker results in no messages
> processed
> --------------------------------------------------------------------------------
>
> Key: QPIDJMS-86
> URL: https://issues.apache.org/jira/browse/QPIDJMS-86
> Project: Qpid JMS
> Issue Type: Bug
> Components: qpid-jms-client
> Affects Versions: 0.3.0
> Reporter: Alex Plischke
>
> My broker's default prefetch policy is set to 0 (using ActiveMQ).
> When my queue consumer connects to the broker, the broker reports that the
> consumer has indeed a prefetch of 0.
> The qpid client however, just uses the defaults defined in the
> JmsPrefetchPolicy class (ergo, 1000 for the queue).
> So when the qpid client tries to decide whether it needs to poll or not in
> JmsMessageConsumer...
> {noformat}
> protected void sendPullCommand(long timeout) throws JMSException {
> if (messageQueue.isEmpty() && (getPrefetchSize() == 0 ||
> isBrowser())) {
> connection.pull(getConsumerId(), timeout);
> }
> }
> {noformat}
> ... the if condition will be false, since the prefetch size returned here is
> 1000. Qpid will therefore not poll and the broker not push either, resulting
> in no messages processed.
> My current workaround is that I have to set the prefetch size on the client
> as well.
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