> On 2011-11-15 16:41:28, Gordon Sim wrote: > > http://svn.apache.org/repos/asf/qpid/trunk/qpid/java/client/src/main/java/org/apache/qpid/client/AMQSession_0_10.java, > > line 796 > > <https://reviews.apache.org/r/2832/diff/1/?file=58392#file58392line796> > > > > You are syncing here while holding the delivery lock, could that cause > > any problems? > > rajith attapattu wrote: > So far I haven't encountered any issues. However things like failover, > session exceptions etc..could cause issues. I'm planning more thorough longer > running tests. > Another thing I am considering is to not use a sync() at all. I'm not > quite convinced that it's of much value here. > > I've noticed that the client continues to get messages into it's queue > even after the code returns from the sync call. Hence the code snippet to > release any messages received after the connection is stopped. I was > expecting the brokers response to the sync command to be received after the > client has got all the messages that were in flight. So after I sync I could > just release the messages in the queue and be done with it. But that's not > the case. > > It seems that the dispatcher thread takes a bit of time to process the > UnprocessedMessages into the correct JMSMessages and put them onto the queue. > So the sync() really doesn't add much value here.
It sounds like it is necessary but not sufficient. You need to know that the stop has been processed by the broker and it will not send any further, but you also need to synchronise with the thread actually processing incoming messages(?). > On 2011-11-15 16:41:28, Gordon Sim wrote: > > http://svn.apache.org/repos/asf/qpid/trunk/qpid/java/client/src/main/java/org/apache/qpid/client/BasicMessageConsumer_0_10.java, > > line 126 > > <https://reviews.apache.org/r/2832/diff/1/?file=58393#file58393line126> > > > > What case(s) is this code required for? You are releasing a message you > > have just received, right? When is that required? > > rajith attapattu wrote: > See the above for an explanation for why this is needed. You mean this is here because of the lack of synchronization with the dispatcher thread? If so that seems a little nasty to me... anyway to do this more cleanly? > On 2011-11-15 16:41:28, Gordon Sim wrote: > > http://svn.apache.org/repos/asf/qpid/trunk/qpid/java/client/src/main/java/org/apache/qpid/client/AMQSession_0_10.java, > > line 787 > > <https://reviews.apache.org/r/2832/diff/1/?file=58392#file58392line787> > > > > Are there any other locks acquired as part of the block here? If so are > > there any lock ordering issues where you could be introducing a deadlock? > > rajith attapattu wrote: > Not that I could think of. The message-delivery-lock is taken to ensure > that no messages are being served while we start pulling them out of the > queue. > In my tests so far, I haven't encountered any issues. However I plan to > have more manual tests - ex. Trying to stop the connection while the message > consumers are in full flight. What about the failover mutex? Could the release trigger a codepath that attempts to acquire that? What about an asynchronous exception occurring concurrently; would that ever need to acquire the message-delivery-lock? - Gordon ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/2832/#review3264 ----------------------------------------------------------- On 2011-11-15 15:36:36, rajith attapattu wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/2832/ > ----------------------------------------------------------- > > (Updated 2011-11-15 15:36:36) > > > Review request for qpid, Gordon Sim, Robbie Gemmell, Weston Price, and > Oleksandr Rudyy. > > > Summary > ------- > > This attempts to fix one of the issues related to the handling of Message > credits. See QPID-3602 for an overall picture of the various issues. > > This particular patch does the following. > 1. When the connection is stopped, it sends message.stop() & releases all > messages in the prefetch buffer. > 2. It will also release any messages (that were in flight) that comes after > the connection is stopped. (*) > > (*) This interferes with the immediate_prefetch feature. However I don't know > if immediate prefetch is really required in the 0-10 path. > > As always comments, suggestions & criticisms are equally welcomed. > > > This addresses bug QPID-3604. > https://issues.apache.org/jira/browse/QPID-3604 > > > Diffs > ----- > > > http://svn.apache.org/repos/asf/qpid/trunk/qpid/java/client/src/main/java/org/apache/qpid/client/AMQSession_0_10.java > 1202228 > > http://svn.apache.org/repos/asf/qpid/trunk/qpid/java/client/src/main/java/org/apache/qpid/client/BasicMessageConsumer_0_10.java > 1202228 > > http://svn.apache.org/repos/asf/qpid/trunk/qpid/java/systests/src/main/java/org/apache/qpid/client/prefetch/PrefetchBehaviourTest.java > 1202228 > > http://svn.apache.org/repos/asf/qpid/trunk/qpid/java/client/src/main/java/org/apache/qpid/client/AMQConnection.java > 1202228 > > Diff: https://reviews.apache.org/r/2832/diff > > > Testing > ------- > > See PrefetchBehaviourTest#testConnectionStop for more details. > > > Thanks, > > rajith > >
