Hi, We noticed a potential problem with the way JMS 2.0 global shared durable subscriptions are implemented in the JMS client. The implementation was designed, discussed, and implemented in QPIDJMS-220 [1].
When a consumer of a subscription closes the underlying AMQP link is not closed but merely detached since the closing of a subscription link is used as the signal to unsubscribe the subscription. These subscription links remain on the broker until the subscription is unsubscribed (detach with close=true) at which point the broker discards all links associated with the subscription. For non-global subscriptions this does not seem to be a problem since the clientId is used as the container-id and links are reused if possible. For global subscription on the other hand the client uses a random UUID associated with the connection as its own container-id. This means that on every new connection a new link is being estblished rather than recovering an existing one. Over time these subscription links would accumulate on the broker until the subscription is unsubscribed. Since shared durable subscriptions are expected to be long lived this raises some concerns with regards to resource exhaustion on the broker. An application that would spin up a connection do some work on a shared durable global subscription and then disconnect again would be "leaking" links. Due to this concern we plan on disabling shared durable global subscriptions for the initial v7 release of Qpid Broker-J. There will be a context variable to enable the feature. Thoughts, comments, discuss! Kind regards, Lorenz [1] https://issues.apache.org/jira/browse/QPIDJMS-220 --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@qpid.apache.org For additional commands, e-mail: dev-h...@qpid.apache.org
