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https://issues.apache.org/jira/browse/QPID-8134?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16567693#comment-16567693
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dan clark commented on QPID-8134:
---------------------------------
Isolated the problem to using the send link properties of 'at-least-once' where
there broker never seems to settle the messages and therefore results in the
qpid-c-client library never releasing any sent message buffers.
in other words: to demonstrate the leak run the shell scripts gospout.sh -a
doSubject (and the corresponding do drain.sh -a doSubject).
The work around is to specify link attributes to the sending (gospout)
application which sets the reliability attribute to 'unreliable' (or
equivalently according to documentation 'at-most-once' as they are synonyms).
per
[https://qpid.apache.org/releases/qpid-cpp-1.38.0/messaging-api/book/section-addresses.html]
Thus updating the examples to avoid the sender leak would look similar to:
./spout 'amq.topic; \{ create: sender, delete: sender, assert: sender, mode:
consume, node: {type: topic, durable: false, x-declare: {auto-delete: true,
ack-frequency: 1, exclusive: true} }*, link: \{ name: pubs-spout, durable:
false, reliability: at-most-once, timeout: 1}* }' \
--content payload \
--topic comp_spout \
--print \
$setexit \
--property 'qpid.subject'=comp_spout \
-c $cnt
Thus by changing the reliability: unreliable, the c++ sending library frees the
memory associated with the send buffer after the message is sent, alleviating
the memory leak.
Speculatively:
Perhaps the bug can be isolated to the behavior between the qpid broker and the
qpid client where for "reliability: exactly-once" the broker is not informing
the client of the message delivery so the client library never cleans up the
message memory.
> qpid::client::Message::send multiple memory leaks
> -------------------------------------------------
>
> Key: QPID-8134
> URL: https://issues.apache.org/jira/browse/QPID-8134
> Project: Qpid
> Issue Type: Bug
> Components: C++ Client
> Affects Versions: qpid-cpp-1.37.0, qpid-cpp-1.38.0
> Environment: *CentOS* Linux release 7.4.1708 (Core)
> Linux localhost.novalocal 3.10.0-327.el7.x86_64 #1 SMP Thu Nov 19 22:10:57
> UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
> *qpid*-qmf-1.37.0-1.el7.x86_64
> *qpid*-dispatch-debuginfo-1.0.0-1.el7.x86_64
> python-*qpid*-1.37.0-1.el7.noarch
> *qpid*-proton-c-0.18.1-1.el7.x86_64
> python-*qpid*-qmf-1.37.0-1.el7.x86_64
> *qpid*-proton-debuginfo-0.18.1-1.el7.x86_64
> *qpid*-cpp-debuginfo-1.37.0-1.el7.x86_64
> *qpid*-cpp-client-devel-1.37.0-1.el7.x86_64
> *qpid*-cpp-server-1.37.0-1.el7.x86_64
> *qpid*-cpp-client-1.37.0-1.el7.x86_64
>
> Reporter: dan clark
> Priority: Blocker
> Labels: maven
> Attachments: drain.cpp, godrain.sh, gospout.sh, qpid-stat.out,
> spout.cpp, spout.log
>
> Original Estimate: 40h
> Remaining Estimate: 40h
>
> There may be multiple leaks of the outgoing message structure and associated
> fields when using the qpid::client::amqp0_10::SenderImpl::send function to
> publish messages under certain setups. I will concede that there may be
> options that are beyond my ken to ameliorate the leak of messages structures,
> especially since there is an indication that under prolonged runs (a
> demonized version of an application like spout) that the statistics for quidd
> indicate increased acquires with zero releases.
> The basic notion is illustrated with the test application spout (and drain).
> Consider a long running daemon reducing the overhead of open/send/close by
> keeping the message connection open for long periods of time. Then the logic
> would be: start application/open connection. In a loop send data (and never
> reach a close). Thus the drain application illustrates the behavior and
> demonstrates the leak using valgrind by sending the data followed by an
> exit(0).
> Note also the lack of 'releases' associated with the 'acquires' in the stats
> output.
> Capturing the leaks using the test applications spout/drain required adding
> an 'exit()' prior to the close, as during normal operations of a daemon, the
> connection remains open for a sustained period of time, thus the leak of
> structures within the c++ client library are found as structures still
> tracked by the library and cleaned up on 'connection.close()', but they
> should be cleaned up as a result of the completion of the send/receive ack or
> the termination of the life of the message based on the TTL of the message,
> which ever comes first. I have witnessed growth of the leaked structures
> into the millions of messages lasting more than 24hours with short (300sec)
> TTL of the messages based on scenarios attached using spout/drain as test
> vehicle.
> The attached spout.log uses a short 10message test and the spout.log contains
> 5 sets of different structures leaked (found with the 'bytes in 10 blocks are
> still reachable' lines, that are in line with much more sustained leaks when
> running the application for multiple days with millions of messages.
> The leaks seem to be associated with structures allocation 'stdstrings' to
> save the "subject" and the "payload" for string based messages using send for
> amq.topic output.
> Suggested work arounds are welcome based on application level changes to
> spout/drain (if they are missing key components) or changes to the
> address/setup of the queues for amq.topic messages (see the 'gospout.sh and
> godrain.sh' test drivers providing the specific address structures being used.
> For example, the following is one of the 5 different categories of leaked
> data from 'spout.log' on a valgrind analysis of the output post the send and
> session.sync but prior connection.close():
>
> ==3388== 3,680 bytes in 10 blocks are still reachable in loss record 233 of
> 234
> ==3388== at 0x4C2A203: operator new(unsigned long)
> (vg_replace_malloc.c:334)
> ==3388== by 0x4EB046C: qpid::client::Message::Message(std::string const&,
> std::string const&) (Message.cpp:31)
> ==3388== by 0x51742C1:
> qpid::client::amqp0_10::OutgoingMessage::OutgoingMessage()
> (OutgoingMessage.cpp:167)
> ==3388== by 0x5186200:
> qpid::client::amqp0_10::SenderImpl::sendImpl(qpid::messaging::Message const&)
> (SenderImpl.cpp:140)
> ==3388== by 0x5186485: operator() (SenderImpl.h:114)
> ==3388== by 0x5186485: execute<qpid::client::amqp0_10::SenderImpl::Send>
> (SessionImpl.h:102)
> ==3388== by 0x5186485:
> qpid::client::amqp0_10::SenderImpl::send(qpid::messaging::Message const&,
> bool) (SenderImpl.cpp:49)
> ==3388== by 0x40438D: main (spout.cpp:185)
>
>
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