On Jan 10, 2011, at 5:02 AM, Jeff Rose wrote:

> On Sat, Jan 8, 2011 at 2:11 AM, Alex Dean <a...@crackpot.org> wrote:
> On Dec 14, 2010, at 9:48 AM, Jeff Rose wrote:
> 
> > Hi Alex,
> >  Thanks for the response.  We looked into it a bit more based on your
> > suggestion, and we discovered that there is an error occurring when the
> > continuation is resumed in onMessageAvailable in AjaxListener.java.  It
> > looks like this onMessageAvailable handler is being called every time a new
> > message arrives on the queue, and then it is trying to resume a continuation
> > that has already been resumed, which causes an illegal state exception.
> > We've been trying to fix the bug  by checking first:
> >
> >   !continuation.isResumed()
> >
> > but we are still getting the error occasionally (although it does often get
> > all of the messages now).  This seems to be a pretty fundamental bug in the
> > AJAX support of ActiveMQ.  Definitely worth posting a ticket (although I
> > don't know where that is done).
> 
> Jeff: I attached a patch to AMQ-3094 which I think fixes this problem.  A 
> continuation can be in more states than just initial & resumed, so checking 
> !continuation.isResumed() can still result in illegal state exceptions.  I 
> changed your suggestion so AjaxListener only tries to resume a continuation 
> "if( continuation.isSuspended() )".  Otherwise it buffers the message for 
> delivery in the next poll (building on some code Dejan committed a few days 
> ago).
> 
> Let me know if you have time to test this patch, and if it solves the issue 
> for you.  It looks good in my tests so far.
> 
> https://issues.apache.org/jira/secure/attachment/12467757/all_messages_are_delivered_to_ajax_clients.patch
> 
> Hi Alex,
>   I'm not able to apply your patch, either to the latest from SVN or to 
> revision 1052368 which is specified in the patch.  For example, in 
> MessageListenerServlet.java I don't have any reference to the 
> unconsumedMessages linked list.  Can you generate the patch against the 
> latest from SVN so I can give it a try?  I've got everything setup again to 
> test with my initial PHP and javascript configuration.

Sure.  I'll update to trunk HEAD and re-send the patch.

unconsumedMessages was added to AjaxListener in r1052259, so if you've got HEAD 
you should have it.  http://svn.apache.org/viewvc?view=revision&revision=1052259

Updated patch (now based on trunk r1057227) is at 
https://issues.apache.org/jira/secure/attachment/12467892/all_messages_are_delivered_to_ajax_clients.2.patch

alex

Reply via email to