Mailing-List: contact activemq-users-help@geronimo.apache.org; run by ezmlm
Precedence: bulk
Reply-To: activemq-users@geronimo.apache.org
Received-SPF: pass (asf.osuosl.org: domain of james.strachan@gmail.com
 designates 72.14.214.202 as permitted sender)
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
        s=beta; d=gmail.com;
        h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references;
        b=HqlT3BSD+CxWVKWD/eqZ8NtNKtMc9exAg/sqYG4Pkl5AeP8fIjKpMdtBtieXSLlq5QVa+0iPFYZp5504qXOkzxSmL4S3TeIoZgW7TVGPNjbtypwHO4oAuS+DuE6QbH28TR9AMb93OdZ4HqykW+lKCJglA8TP3JBpS18LYFR7Iq4=
Message-ID: <ec6e67fd0606190909i52dd8948y4465233e406fc934@mail.gmail.com>
Date: Mon, 19 Jun 2006 17:09:34 +0100
From: "James Strachan" <james.strachan@gmail.com>
To: activemq-users@geronimo.apache.org
Subject: Re: detaching message group affinity
In-Reply-To: <a17839be0606190904w31b6fd07j7dc6ef4fb701f36a@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
References: <a17839be0606161754g531010afhb4c2c68ed6e0dd7f@mail.gmail.com>
	 <ec6e67fd0606190749u557c6557o2c4d76c2abc30730@mail.gmail.com>
	 <a17839be0606190811g4d27f7b7l2576b0cf4fb82402@mail.gmail.com>
	 <ec6e67fd0606190817h15083f56tbf95a667687db1ee@mail.gmail.com>
	 <a17839be0606190841l2f124889r342143ee7398276b@mail.gmail.com>
	 <ec6e67fd0606190845l441df93do49f0ee0033c02623@mail.gmail.com>
	 <a17839be0606190904w31b6fd07j7dc6ef4fb701f36a@mail.gmail.com>

On 6/19/06, Sanjiv Jivan <sanjiv.jivan@gmail.com> wrote:
> On 6/19/06, James Strachan <james.strachan@gmail.com> wrote:
> >
> >
> > > Who is the owner of the "JMSXGroupID" to broker mapping? Is it the JMS
> > > Connection or a JMSSession? I need to send messages by different Message
> > > Groups from the same client application. I would like to understand if I
> > > need to create separate JMS Connections for each message group based
> > > conversation, or separate JMS Sessions would suffice. A quick look at
> > the
> > > source seems to indicate that Message Groups are held at the JMS
> > connection
> > > level (ActiveMQConnectionMetaData). Can you confirm?
> >
> > A broker manages Message Groups for its consumers. Its nothing to do
> > with connections per se - its purely a mapping of JMSXGroupID to
> > message consumer in a broker.
>
>
> A consumer being the value in JMSReplyTo?

Not necessarily - a consumer being some POJO created via
Session.createMessageConsumer().

But if the consumers are using temporary queues/topics then they are
nearly the same thing.


> I guess what I'm having difficulty
> understanding is where is the correlation between a single message with "
> message.setIntProperty("JMSXGroupSeq", 0);" to MessageGroupID being made. Is
> it based on JMSReplyTo value provided by the producer sending the message?


If someone is sending a message and they want to 'close' a message
group, they set the JMSXGroupSeq header along with the JMSXGroupID
header.

If some other node who is not a JMS sender wants to close a message
group, you could always just send a dummy message.


> What is the expected behaviour in such a scenario (this is related to issue
> AMQ-760): A network of 2 brokers has been set up. A client sends several
> messages to MG1 and MG2 which are received by SERVER1 and SERVER2
> respectively. The client process terminates (ie the JMSConenction,
> session etc are destroyed). The client comes up an send messages to MG1 and
> MG2. Is is guaranteed that MG1 and MG2 go to the designated servers from the
> previous run (SERVER1 and SERVER2 respectively).

Message groups is a broker-side thing; the only thing which affects
which consumer is associated with a message group is

* when the consumer is closed (e.g. as a result of a Connection
close), its message groups are put back in the pool to be re-assigned
to a consumer

* if the message group is explicitly closed by a message containing a
JMSXGroupId and a JMSXGroupSeq of value 0

-- 

James
-------
http://radio.weblogs.com/0112098/