Hello,
Using Qpid JMS 0.11.0 AMQP 1.0 client, which is the latest version for
Java 7, we experienced an issue when you set prefetch > 1 and start
consuming messages from a queue in asynchronous mode, using
"onMessage()" method and sessionMode = Session.CLIENT_ACKNOWLEDGE.
Taking prefetch= 10 as example, I noticed that:
1. When you open connection/session/listener, the client sends a "flow"
performative with linkCredit=10, which is correctly the prefetch
value. Prefetched messages = 10
2. The client starts to process the first message received using class
"MessageDeliverTask" method "run()" (all inside JmsMessageConsumer.java)
3. There is a call "ackFromReceive(envelope)" at row 667 which,
following sub-calls, will call method "sendFlowIfNeeded()" of class
"AmqpConsumer"
4. in this method "newCredit" is calculated to send a new "flow"
performative. Here the calculation doesn't check how many prefetched
messages already are on client side. The currentCredit is 0, for
this reason is sent a "flow" performative with linkCredit=10.
Prefetched messages =20
5. There is a call "messageListener.onMessage(copy);" at row 672 which
triggers the import of the message. Then the prefetched messages = 19.
6. The process starts again from point 2 increasing constantly the
prefetched messages collected on client side, causing timeout issues
because if they are 1 million of messages, the client can't process
them before they expire
I compared code of method "sendFlowIfNeeded()" (see point 3) in version
0.11.0 with the code of version 0.31.0: in version 0.31.0 the code is
changed and the calculation considers also "prefetchMessageCount".
Is this a known issue? Will you fix it for 0.11.x version because it is
the latest version for Java 7?
Best Regards
--
SMC Consulting <http://www.smcconsulting.it>
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*Alessandro Crotti*
Senior Developer
tel: +39 342 573 4450
skype: crotti.alessandro
*SMC Consulting* <http://www.smcconsulting.it>
Via dell'industria, 87 41012 Carpi (MO) - Italy
tel: +39 059 664875
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