On 3/5/07, rbector <[EMAIL PROTECTED]> wrote:
Hello I am currently evaluating the feasibility of using ActiveMQ for our system (which is a bunch of applications who want to interact using JMS). I had a few questions which I thought some of you may have answers to: 1) We'd prefer to use the embedded version of the broker. All communicating applications would use the embedded broker so there would be no *server* running. I've read that this Topology is supported by ActiveMQ. What are the downsides of using this topology ? The upsides to me are - higher performance because of one less hop and less maintenance. Comments ?
The main downside is managing persistent state. Using embedded brokers means each process has a bunch of persistent files and/or database. If you've tons of processes this becomes unwiedly soon, so running separate brokers is often easier.
2) I would like to have the ability to create topics such that messages on them are never deleted. Essentially, any consumer could attach to the topic any point in time (even 30 days after the topic was created) and receive older messages (Ideally - it should have the choice to start receiving messages from a certain point in time in the past or from a certain ID). The idea behind this approach is that consumers are more decoupled. They could process some messages, checkpoint them internally and go away and come back later. I would like to try to understand if this is directly or indirectly supported in ActiveMQ (or other JAVA based messaging systems that people know of)
Its generally not supported by JMS but we've some extensions you can use to do this kind of thing... http://activemq.apache.org/subscription-recovery-policy.html
3) If there are n consumers interested in a certain topic, some of the consumers may be away when messages on that topic are published. Whats the behavior of ActiveMQ in such a scenario ? Is the subscription information maintained on a persistent basis (we'd like it to be). (This is also in the context of embedded broker - the broker is embedded inside the producers/consumers)
It depends if you are using a durable topic consumer or not. If you are, then yes it is. Otherwise no :). -- James ------- http://radio.weblogs.com/0112098/
