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From Francesco PADOVANI <Francesco.PADOV...@bticino.it>
Subject Re: MQTT retained messages with weird characters
Date Wed, 11 Jan 2017 09:22:28 GMT
Unfortunately no (not yet).

Anyway, it's a clean Artemis installation of version 1.5.1, made by following the user manual
instructions at https://activemq.apache.org/artemis/docs/1.5.1/using-server.html.

The installation was done by using a dedicated user and also the artemis java process runs
with this dedicated user. Attached you can find my broker.xml configuration file: it's pretty
much the same default created during the installation procedure, but for the acceptors (which
I've customized for my MQTT purpose) and the addition of parameter "<last-value-queue>true</last-value-queue>"
inside the address-setting section (but I tried with and without it and my issue persists).

The only other configuration I changed is the heap size dedicated to the process, by setting
"-Xms4096M -Xmx4096M" among the JAVA_ARGS in the artemis.profile file.


The platform where Artemis broker is installed is:


- Machine:

It's an EC2 instance on AWS cloud of type m4.large: 2 vCPU, 8G RAM and SSD storage.


- OS:

CentOS Linux release 7.3.1611 (Core) - x86_64


- JVM:

java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)


- Distro package version of libaio:

Arch        : x86_64
Version     : 0.3.109
Release     : 13.el7


It seems like the problem relates the Persistence (File Journal?). Until the broker keeps
the retained messages in ram it works. When it needs to recover the retained messages  from
the file system, clients receive them with weird chars.
And I suspect the same issue appears when RAM is full and messages start to be paged... but
this case is a bit more difficult to test in a systematic way.


Francesco


________________________________
From: Clebert Suconic <clebert.suconic@gmail.com>
Sent: Tuesday, January 10, 2017 7:43 PM
To: users@activemq.apache.org
Subject: Re: MQTT retained messages with weird characters

Do you have a working test you can share?

On Tue, Jan 10, 2017 at 12:07 PM, Francesco PADOVANI
<Francesco.PADOVANI@bticino.it> wrote:
> Hello,
>
> I'm trying the Apache Artemis Broker (ver. 1.5.1) for MQTT protocol.
>
> Exactly I'm testing the retained feature for messages of MQTT protocol.
>
> While the broker is up it seems to work well:
>
> a) a client publishes a retained message to a specific topic
>
> b) any client which then subscribes that topic receives the retained message (any time
it re-subscribes the topic it receives the last retained message ...perfect!)
>
> But it happens a strange thing when I restart the broker. And I mean I restart the broker
without any change on configuration: simply I make a "artemis-service stop" and "artemis-service
start". After The broker is up and running, if a client subscribes the previous topic it still
receives the retained message, but with weird characters appended to it. For new retained
messages published it work well again... but the previous ones (before the broker restart)
are sent all with these weird characters. E.g., the following is a retained message published
before the broker restart:
>
> "test 25 for a retained message 20170110"
>
> And this is exactly how clients get it before the broker restart.
>
> Instead, after broker restart, the same retained message is received by clients in the
following way:
>
> test 25 for a retained message 20170110?
>                                         ? 6$sys.mqtt.retain..cro.test5 ?  &mqtt.message.retain
? mqtt.qos.level
>
>
> Is this my bad configuration (but I don't know ehere)? Or anything else? Or what?
>
> Someone can help me?
>
>
> Thanks in advance.
>
>
> Francesco
>
> ________________________________
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--
Clebert Suconic

________________________________

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