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Posted to dev@qpid.apache.org by "Gordon Sim (JIRA)" <ji...@apache.org> on 2011/07/14 14:40:59 UTC
[jira] [Commented] (QPID-3356) Dynamic Federation doesn't work as
expected for headers exchange
[ https://issues.apache.org/jira/browse/QPID-3356?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13065213#comment-13065213 ]
Gordon Sim commented on QPID-3356:
----------------------------------
The AMQP spec requires the exchange+queue+bindingkey triple to be unique, however the headers exchange implementation does not enforce this. That is the cause of the error message about duplicate management objects with the same identifier - the binding is identified by that triple which should be unique. That is also the cause of the duplicated message. Therefore there is a bug in the basic headers exchange implementation itself where it needs to enforce this uniqueness. (How it should do that is an interesting question - should it reject or ignore attempts to bind with different args but the same exchange+queue+biningkey?)
However there is also a bug in the handling of dynamic federation. For the headers exchange the propagated bindings can't use the original binding key or cases like above would either fail or one part of the subscription would be lost.
> Dynamic Federation doesn't work as expected for headers exchange
> ----------------------------------------------------------------
>
> Key: QPID-3356
> URL: https://issues.apache.org/jira/browse/QPID-3356
> Project: Qpid
> Issue Type: Bug
> Components: C++ Broker
> Affects Versions: 0.13
> Reporter: Gordon Sim
>
> start two brokers, link amq.match using a dynamic route in one direction, start two subscribers on the destination broker (e.g two drain instances from amq.match; {link:{x-bindings:[{arguments:{source:B, x-match:any}}]}} and amq.match; {link:{x-bindings:[{arguments:{format:standard, x-match:any}}]}} respectively), you then see the following error appear on the source broker after a second or so:
> error Detected two management objects with the same identifier: 0-614-1--18(org.apache.qpid.broker:binding:org.apache.qpid.broker:exchange:amq.match,org.apache.qpid.broker:queue:bridge_queue_1_a51ddbb5-bac4-4e6a-ba45-3a2e1b096858,)
> Further, duplicate messages can then be received at the subscribers. E.g. send a message to the source broker that matches each subscriber and observe that the message is received twice by each of them (e.g. spout --content my-message -P format=standard -P source=B amq.match)
> This appears to be due to the same binding key being used for two different subscriptions. E.g. if you changes the addresses for the drains above to: amq.match; {link:{x-bindings:[{key: key1, arguments:{source:B, x-match:any}}]}} and amq.match; {link:{x-bindings:[{key: key2, arguments:{format:standard, x-match:any}}]}} respectively, i.e. add unique keys to each, then you avoid the error and the message duplication.
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