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Re: [Artemis 2.6.2] AMQP messages going to expiry queue, redelivery off that queue is failing


On 08/30/2018 07:10 PM, Dan Langford wrote:
thanks for looking into this. what is the proper way to force for testing a
redelivery that goes back to the broker without transactions? its probably
like killing the session or connection. that would be if we wanted to test
if non-transacted redeliveries were getting corrupted

The issue has been identified and fixed, should appear in the next release.
https://issues.apache.org/jira/browse/ARTEMIS-2082


we have a lot of people using spring-jms and as i look in the spring code...
https://github.com/spring-projects/spring-framework/blob/master/spring-jms/src/main/java/org/springframework/jms/listener/AbstractMessageListenerContainer.java
looking at doExecuteListener and rollbackOnExceptionIfNecessary
it looks like if its transacted they try to rollback() and if its
client_ack they try recover(). they probably dont handle auto_ack because
that was acked immediately?

speaking of this what is an appropriate way to NACK a message when using
Client Acknowledgemnt and a JMS messageHandler? is it simply to reach the
end of the method execution without having called message.acknowledge() or
would it be appropriate to throw a RuntimeException (since i cannot throw a
checked Exception out of an implementation of javax.jms.MessageListener) ?

On Thu, Aug 30, 2018 at 8:38 AM Robbie Gemmell <robbie.gemmell@xxxxxxxxx>
wrote:

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 <danlangford@xxxxxxxxx> 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 <tabish121@xxxxxxxxx>
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



--
Tim Bish
twitter: @tabish121
blog: http://timbish.blogspot.com/