Red Hat Bugzilla – Bug 871774
Browser may read messages acquired by other consumer on message group queue
Last modified: 2013-03-06 13:52:38 EST
Description of problem: Automated tests shows that the way of browsing message group queue has changes. When browsing a message group queue, the browser can see messages acquired-but-not-acknowledged by other consumers. This is message group queue related issue, common queues do not suffer from that. Version-Release number of selected component (if applicable): qpid-cpp-*-0.18-2 How reproducible: 100% Steps to Reproduce: run the following single test from qpid_ptest_unit_test: custom_py_units.queue.HLAPITests.test_message_groups_sequenced_consumers_common If you need further instruction how to execute the test, please visit: https://wiki.test.redhat.com/MRG/MRGQETestInfrastructure#Customunittestbasedonqpidpythontest OR 1. create a message group queue an enqueue several messages 2. acquire a message from that queue, but do not acknowledge yet 3. browse the queue with other client, and realize that the acquired message is listed Actual results: Browser can read already acquired messages Expected results: Same approach as on common queue, the acquired messages can't be read by the browser. Additional info:
I think I have a fix for this: diff --git a/qpid/cpp/src/qpid/broker/MessageGroupManager.cpp b/qpid/cpp/src/qpid/broker/MessageGroupManager.cpp index bc5d797..c30f009 100644 --- a/qpid/cpp/src/qpid/broker/MessageGroupManager.cpp +++ b/qpid/cpp/src/qpid/broker/MessageGroupManager.cpp @@ -260,7 +260,7 @@ bool MessageGroupManager::allocate(const std::string& consumer, const QueuedMess bool MessageGroupManager::nextBrowsableMessage( Consumer::shared_ptr& c, QueuedMessage& next ) { // browse: allow access to any available msg, regardless of group ownership (?ok?) - return messages.browse(c->getPosition(), next, false); + return messages.browse(c->getPosition(), next, !c->browseAcquired()); } void MessageGroupManager::query(qpid::types::Variant::Map& status) const this allows the reproducer to pass, but for some reason one of the message groups unit test is failing. I'll have to look at it a bit more.
Ok, I understand this a bit more: There was a change to the qpid::broker::Consumer class that added a flag that controlled whether acquired messages are browsable [Consumer::browseAcquired()]. This flag defaults to false (do not browse acquired messages). The msg group code was not updated to reference this flag. The following patch is also needed to correct one of the message group tests: diff --git a/qpid/tests/src/py/qpid_tests/broker_0_10/msg_groups.py b/qpid/tests/src/py/qpid_tests/broker_0_10/msg_groups.py index ace7611..c9c498b 100644 --- a/qpid/tests/src/py/qpid_tests/broker_0_10/msg_groups.py +++ b/qpid/tests/src/py/qpid_tests/broker_0_10/msg_groups.py @@ -767,10 +767,10 @@ class MultiConsumerMsgGroupTests(Base): 'filter_params' : { 'header_key' : "THE-GROUP", 'header_value' : "A" }} assert queue.msgDepth == 6 - rc = queue.purge(1, msg_filter) + rc = queue.purge(1, msg_filter) # should purge A-2 (first available) assert rc.status == 0 queue.update() - queue.msgDepth == 5 # the pending acquired A still counts! + queue.msgDepth == 4 # verify all other A's removed.... s2 = self.setup_session() @@ -787,7 +787,7 @@ class MultiConsumerMsgGroupTests(Base): except Empty: pass assert count == 3 # non-A's - assert a_count == 2 # pending acquired message included in browse results + assert a_count == 1 # Only one (unacquired) A msg s1.acknowledge() # ack the consumed A-0 self.qmf_session.delBroker(self.qmf_broker) It appears that the test was incorrectly modified to work with browsing acquired messages as part of the original patch that added the browseAcquired() flag. Justin - do you agree?
This all makes sense to me. Thanks, Ken.
This issue has been fixed in the broker (qpid-cpp-0.18-6). qpid-tests package needs to be rebuild to correct the unit test mentioned in comment 4 (successfully tested with the patch). Leaving open until that time.
This issue has been fixed. Verified on rhel5 and rhel6 (both i386,x86_64) packages used for testing: qpid-cpp-*-0.18-7 -> VERIFIED
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHSA-2013-0561.html