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From Michael André Pearce <>
Subject Re: ActiveMQConnectionFactory: use initial connectors instead of received topology
Date Thu, 03 Aug 2017 16:32:37 GMT
We saw this too when running cluster mode and static discovery before we moved to UDP and then
finally went to single master cluster due to cost in some support licensing as had to reduce
cpu counts.

Sent from my iPhone

> On 3 Aug 2017, at 17:31, Michael André Pearce <> wrote:
> The bit I'm getting at is it uses the discovery connection when on static instead of
discovering getting the topology and then using that to make the connection.
> This is why when using topology and static you see first two connections to same host
as it uses the discovery connection first which for sake of discussing host a is first in
list, and then the next uses the topology one where host a is first in list as such this is
why it makes to connections to host a before it makes one to host b.
> Sent from my iPhone
>> On 3 Aug 2017, at 14:59, Clebert Suconic <> wrote:
>> On Thu, Aug 3, 2017 at 9:01 AM, Michael André Pearce
>> <> wrote:
>>> But what I'm saying is should it be that the discovery should happen but then
the real connection is made from the returned topology. Like for UDP instead of hoodwinking
on the discovery connection.
>> I'm not understanding your point here? the connection factory will
>> always receive a list of the topology (No matter if UDP or TCP) and
>> load balance based on the topology returned.
>> There are users using this as a feature.
>> What I think is needed here is a simple property to the connection
>> factory, like.... useTopololgy, connectOntTopology (or please help me
>> find a better name).
>> then you could connect with:
>> ActiveMQConnectionFactory factory = new
>> ActiveMQConnectionFactory((tcp://NODE1:61616,tcp://NODE2:61616)?blockOnDurableSend=false&useTopology=false");
>> I"m not sure if useTopology would make it clear.. I'm still thinking
>> about a better name.
>>> Sent from my iPhone
>>>> On 3 Aug 2017, at 12:52, Clebert Suconic <>
>>>> It is not a bug. People use this to feed an initial list than the topology
>>>> could be much bigger.
>>>> On Thu, Aug 3, 2017 at 1:18 AM Michael André Pearce <
>>>>> wrote:
>>>>> To me this sounds like a bug, where you get two connections because you
>>>>> use two lists.
>>>>> as in why doesn't it use the topology list straight away? Fair enough
>>>>> discovery of that topology is should temporarily make a connection using
>>>>> the static connections, but it should disconnect and reconnect using
>>>>> topology. I.e. It should just discover the topology using the static
>>>>> discovery list.
>>>>> Similar to udp discovery it simply discovers then it uses the topology
>>>>> returned.
>>>>> Sent from my iPad
>>>>>> On 3 Aug 2017, at 04:59, Clebert Suconic <>
>>>>> wrote:
>>>>>> I agree we could add an option. We could use the URI parameters Thought
>>>>> as
>>>>>> a beanUtils?
>>>>>>> On Wed, Aug 2, 2017 at 11:36 PM Justin Bertram <>
>>>>> wrote:
>>>>>>> I agree there should be an option to stick with the "initial"
>>>>>>> rather than being forced to use the topology.  This would be
an option
>>>>> on
>>>>>>> the Netty connector.  I think "useTopology" (defaults to true)
would be
>>>>> a
>>>>>>> good name.
>>>>>>> Justin
>>>>>>> On Wed, Aug 2, 2017 at 9:28 AM, cjaniake <>
>>>>>>> wrote:
>>>>>>>> Hi there, I have been using the ActiveMQ Artemis JMS interface
>>>>>>>> JNDI.
>>>>>>>> We are not using server discovery, we use static connectors
>>>>>>>> In the connection factory configuration we supply a list
of hosts, that
>>>>>>> are
>>>>>>>> located on two different datacenters, acting as two different
>>>>>>>> Using the RoundRobinConnectionLoadBalancingPolicy we expected
>>>>> connect
>>>>>>>> to
>>>>>>>> every server on the list, but that was not what happened.
>>>>>>>> Debugging the code we realized that, after connecting to
the first
>>>>>>> (random)
>>>>>>>> host on the list, the Server Locator do not use the initial
>>>>>>> list
>>>>>>>> anymore, it uses the received topology for the next connections.
>>>>>>>> We understand this might be useful in simpler scenarios,
but this is
>>>>> not
>>>>>>>> working for us.
>>>>>>>> On a sandbox environment we have even tried to remove the
>>>>>>>> connection
>>>>>>>> configuration, for the servers to act on a stadalone manner,
but even
>>>>>>>> though
>>>>>>>> the server locator acts the same way, receiving a "topology"
of only
>>>>> one
>>>>>>>> node and restrict the next connections this one host.
>>>>>>>> There is a number of problems and inneficiencies we see on
>>>>> approach.
>>>>>>>> If we have a cluster with 3 hosts for example, and we declare
those on
>>>>>>> the
>>>>>>>> host list and get 3 connections using the round robin policy,
we would
>>>>>>>> expect to get one connection for each host. But that's not
>>>>> happens.
>>>>>>>> The
>>>>>>>> load balancing policy starts iterating over one list (the
>>>>>>> connector
>>>>>>>> list) and after the first successfull connection it continues
>>>>>>>> over
>>>>>>>> another list (the received topology), so most of the time
you would get
>>>>>>> two
>>>>>>>> connections to the same host and none for one of them.
>>>>>>>> In a scenario like we have here, with two clusters in different
>>>>>>> locations,
>>>>>>>> it is even worse.
>>>>>>>> We would like to know if we there is an option other than
creating a
>>>>>>>> connection factory for each host we want to use, and if we
can propose
>>>>> an
>>>>>>>> improvement.
>>>>>>>> We are willing to contribute with the development, if we
have an
>>>>>>>> understanding on a possible solution for that problem.
>>>>>>>> Thank you very much.
>>>>>>>> --
>>>>>>>> View this message in context:
>>>>>>>> ActiveMQConnectionFactory-use-initial-connectors-instead-of-
>>>>>>>> received-topology-tp4729166.html
>>>>>>>> Sent from the ActiveMQ - User mailing list archive at
>>>>>> --
>>>>>> Clebert Suconic
>>>> --
>>>> Clebert Suconic
>> -- 
>> Clebert Suconic

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