Tim and I had an initial look at this, and can see generally where the broker is internally corrupting things on send, though not yet the full picture how it gets there or what to do about it. The expiration is likely to be key, one difference with the non-transacted case is actually going to be because its using recover() which the client performs locally.
Robbie On Wed, 29 Aug 2018 at 06:23, Dan Langford <danlangf...@gmail.com> wrote: > > ok i wrote 3 test files. I don't know the best way to get them to you > easily. hopefully a Gist is ok. > https://gist.github.com/danlangford/071e738225ec0c68dd470816b977499b > > you can copy those 3 files straight to > ./tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/amqp > > The test JMSTransactedRedeliveryTest::testAMQPProducerAMQPConsumer proves > that a transacted client can .rollback() a handful of times and still be > able to consume the redelivered message later on. > > The test JMSTransactedRedeliveryBugTest::testAMQPProducerAMQPConsumer shows > that if a message had been expired and now a transacted client is > attempting to consume it the client only has 2 chances before the broker > starts sending the message in a way that will not parse correctly > > The test JMSNonTransactedRedeliveryBugTest::testAMQPProducerAMQPConsumer shows > that if a message had been expired a non-transacted client has no troubles > reliably accessing the redelivered message from broker > > > as you can tell i am mostly concerned about AMQP->AMQP for my use case. > some of those other combos are failing some of these tests in other ways. > naturally you can address those as you see fit but for my client the > AMQP->AMQP is a roadblocker. > > > let me know if you can determine why the broker is sending an extra null > character in the payload on the third time the messages attempts delivery. > maybe we are doing something incorrectly. > > > This has been more of an issue than i thought due to the fact that Spring > default to enabling transactions. in all of my initial tests i couldn't > reproduce it because i prefer the straight simplified jms api from 2.0 and > that defaults to sessions not being transacted. that being said nearly all > of my clients prefer using Spring Boot autoconfigurer and other spring > pieces which happen to default to transacted sessions. i can now have some > of them workaround but others of them are requiring the transaction. > > > also as a reminder and for context here is a link to the initial > conversation i had with the Qpid Jms Client devs who pointed out to me the > erroneous null character in the message transfer from the broker: > https://lists.apache.org/ > thread.html/b1fd9c09a1f66f5529601a8651fbb96585c011b22bbd84e07c4f23b1@%3Cusers.qpid.apache.org%3E > > > thank you so much for your time > > On Tue, Aug 14, 2018 at 1:19 PM Timothy Bish <tabish...@gmail.com> wrote: > > > On 08/13/2018 07:12 PM, Dan Langford wrote: > > > some of my users are attempting a pattern to deduplicate messages based > > on > > > a time window instead of a fixed amount of space (a duplicate id cache) > > > > > > so far the concept has been working very well. So they send their AMQP > > > messages (qpid-jms-client) into a Last Value Queue with an appropriate > > > identifier in the _AMQ_LVQ_NAME. They also set a TimeToLive on the > > message > > > that is essentially the lag they will allow as they want to wait for > > > possible duplicates. If any duplicates come in the Last Value Queue > > > behavior is replacing the older message with the newer message until the > > > expiration. expired messages are delivered to the preconfigured expiry > > > queue where their application is listening. This is not perfect but its > > not > > > intended to be. Its just intended to reduce additional unnecessary > > > processing and they understand this is not a guarantee. It really helps > > > with a system that produces messages in a way that has flurries of > > > "notifications" about the same assetID over and over again. > > > > > > BUT where we are seeing is a problem is when we are consuming from the > > > queue used to hold expired messages and we toss some exception and the > > > message needs to be redelivered. the first time or two the message is > > > redelivered it is delivered OK. But when the JMSXDeliveryCount is about 3 > > > or 4 (we use redelivery delay and multipliers to spread these out) our > > > qpid-jms-client stops being able to read the messages. > > > > > > we were only able to reproduce this when an AMQP message expired onto the > > > queue. (expired from a LVQ in case that is relevant). if we place the > > > message directly on a queue and test different exception and redelivery > > > scenarios we cannot reproduce this behavior. > > > > > > i enable the qpid-jms-client frame logging (via env variable > > > PN_TRACE_FRM=true) and i saw that in the situation when the client code > > > cannot access the payload, even though the broker WAS still sending the > > > payload. so i thought it was some odd issue with the client. The Apache > > > Qpid team responded that the issue seems to be that the broker starts to > > > send some ill formed payloads in this scenario. i dont want to repeat the > > > stack traces and their response, you can read those here > > > > > > > > https://lists.apache.org/thread.html/b1fd9c09a1f66f5529601a8651fbb96585c011b22bbd84e07c4f23b1@%3Cusers.qpid.apache.org%3E > > > > > > would it be helpful if i tested that this happens if there is not a LVQ > > > involved? i could have a message in a non-LVQ expire to another queue and > > > see if redeliveries over their get messed up after a few attempts. For > > the > > > record this is AMQP for producing and consuming. i do notice the messages > > > waiting in the expiry queue have much more headers messages sent directly > > > to a queue from client code. they seem to be headers full of information > > > about the message as it left the previous queue. I tried to send a > > message > > > directly to the expiry queue with all these headers to determine if it > > was > > > the existence of one of these specifically that trigger the malformed > > frame > > > but was not able to fully set all those headers. the JMSDeliverCount > > (type > > > Long) was the one that the client would not let me set and as a result i > > > could not test. for clarity thought i dont know that the issue exists due > > > to a header that is just what i saw as a difference between messages be > > > delivered to the queue by client code versus messages expiring from one > > > queue to another. > > > > > > please look over the linked thread on the qpid list and let me know if > > you > > > know why a message transfer fram would become malformed after a few > > failed > > > deliveries only if the message expired onto the current queue. > > > > > > thanks so much > > > > > > > A great place to start is to create a unit test that reproduces the > > issue. You can look at the Artemis unit tests for AMQP to get some > > inspiration on how to set one up. Then try and create the smallest > > possible test that can reproduce the issue to make it easier to narrow > > in on where the issue might be. > > > > The AMQP tests in Artemis are located here: > > > > > > https://github.com/apache/activemq-artemis/tree/master/tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/amqp > > > > > > > > -- > > Tim Bish > > > >
