Hi HasithaH, According to a little reading i did with the amqp spec regarding topic behavior (refer mail "Behavior of non-durable AMQP topics in MB 3.0.0") ;
- We have control over how to implement message queues (stored queues) for an exchange. So, the decision to have one storage queue for multiple subscribers on the same node for a single non-durable topic is ours to make. - Temporary exchanges last until the server shuts-down. Lifecycle of a non-durable topic ends only in a server shut-down. (Subscribers can come and go) - Temporary message queues last until the server shuts-down. Lifecycle of a temporary message queue (like the one we use here) should therefore clear when the server shuts down. Given above findings, spec-wise, it is okay for a new non-durable topic subscriber to receive past messages of the topic. (valid for the current server session). If consumers expect a subscriber to receive only new messages, I feel that they should use durable topics. Correct me if I'm wrong :) ----------------------------------------------------------------------------------------------------------------------------------------------- There is also a solution (one approach), as we discussed, to use the "subscriber-subscribed-timestamp" against "message-arrival-time" to block messages coming from the past for that subscriber. (This could be done in evaluateDeliveryRules method ? ) WDYT ? Btw theres a jira related to this : https://wso2.org/jira/browse/MB-863 :) Thanks On Tue, Nov 25, 2014 at 6:11 PM, Hasitha Hiranya <hasit...@wso2.com> wrote: > Hi, > > There is an identified concern on the $Subject. > > We are saving topic messages to durable store to share the messages across > the nodes and prevent OOM. > > Consider following scenario > > 1. Sub1 >> subscribes to topic1 on MB1 node > 2. Sub2 >> subscribes to topic1 on MB1 node > 3. Sub3 >> subscribes to topic1 on MB1 node > > Sub1 closes. > We cannot delete messages as messages are shared by all subscribers for > topic1 (Sub2 and Sub3 are still alive) > > Now > > Sub4 >> subscribes to topic1 on MB1 node > > It will get above mentioned messages which we did not delete (we just send > message to all relevant subs on the node). > > But as per topic behavior this should not happen. What would be possible > solutions for this? In MB 2.2.0, we did not get this problem as messages > were fire-and-forget (without considering acks, but in MB 3.0.0 we consider > acks for topic messages). > > What would be the possible solutions? > > Thanks > -- > *Hasitha Abeykoon* > Senior Software Engineer; WSO2, Inc.; http://wso2.com > *cell:* *+94 719363063* > *blog: **abeykoon.blogspot.com* <http://abeykoon.blogspot.com> > > > _______________________________________________ > Architecture mailing list > Architecture@wso2.org > https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture > > -- Cheers, Hasitha Amal De Silva Software Engineer Mobile : 0772037426 Blog : http://devnutshell.tumblr.com/ WSO2 Inc.: http://wso2.com ( lean.enterprise.middleware. )
_______________________________________________ Architecture mailing list Architecture@wso2.org https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture
