Re: [opendds-main] Possible memory leak in v 2.3-RT14855-1

[Leeland A. <la...@re...>]

Hello Adam,



LOL I didn’t notice your signature line. :^) I’d have to get some
authorization to spend cash.



Your comment on the history keeping might indeed be the issue. I found
another section of code that had this additional comment:



  //We don't want to lose any messages so setting the history to keep all
and set limits to unlimited

  dr_qos.history.kind = DDS::KEEP_ALL_HISTORY_QOS;

  dr_qos.resource_limits.max_samples = DDS::LENGTH_UNLIMITED; //This is the
default, just calling it out

  dr_qos.resource_limits.max_instances = DDS::LENGTH_UNLIMITED; //This is
the default, just calling it out

  dr_qos.resource_limits.max_samples_per_instance = DDS::LENGTH_UNLIMITED;
//This is the default, just calling it out



Which seems wrong to me. What we really want is for all messages to be
assured of being passed on to the subscribers. What would you recommend I
set these parameters to?



As far as the id_ I am still trying to figure out where that is set, how it
is tracked, etc.



+ Leeland





*From:* Adam Mitz [mailto:mi...@oc...]
*Sent:* Tuesday, November 08, 2011 9:03 AM
*To:* Leeland Artra
*Cc:* ope...@li...
*Subject:* Re: [opendds-main] Possible memory leak in v 2.3-RT14855-1



Hi Leeland,

On 11/8/2011 10:55 AM, Leeland Artra wrote:

Hello Adam,



I inherited this issue and am a total newbie for OpenDDS. I am reading up
on ACE and OpenDDS. So I might be wrong on my answers.



> Let's hear a bit more about how you're using it. In particular, are you
using any non-default QoS policies?

For QoS policies there is a setting for:



  DDS::TopicQos durable_qos;

  dp_->get_default_topic_qos(durable_qos);

  durable_qos.reliability.kind = DDS::RELIABLE_RELIABILITY_QOS;

  durable_qos.reliability.max_blocking_time.sec = 10;

  durable_qos.reliability.max_blocking_time.nanosec = 0;

// [... some error code ...]

  DDS::DataWriterQos dw_qos;

  pub_->get_default_datawriter_qos(dw_qos);

  pub_->copy_from_topic_qos(dw_qos, durable_qos);

  dw_qos.history.kind = DDS::KEEP_ALL_HISTORY_QOS;




OK, so OpenDDS is configured to "keep all" DataWriter history.  This is
probably accounting for the memory use.


> The comment in the IDL snippet indicates that "id_" is the key field, is
that right?



Not 100% sure but I think so too.




See the corresponding #pragma in the IDL.


> Are you registering and/or disposing any instances?  How many instances
are alive?

> (My guess is that OpenDDS is intentionally keeping that memory to manage
the various instances).

I am unsure how to figure this out. I think there is one instance created
per connection and I managed to reproduce this memory leak like behavior in
a lab environment I created where this is one publisher and one subscriber.




If there is only one instance, and id_ is the key, that would mean that
every sample sent has the same id_.  (Or instances are explicitly
disposed/unregistered.)


Maybe we can IM chat on this if you are willing.




We can do that as part of our commercial support services.
http://www.opendds.org/support.html

Thanks,
Adam Mitz
Senior Software Engineer
Object Computing, Inc.