When is the message deleted in a pub-sub delivery mechanism?
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Posted By:   Itoyjaved_C
Posted On:   Thursday, January 23, 2003 11:08 PM

Hi All,


Like in the p2p mechanism the message gets deleted from the
Q as soon as it is consumed by the consumer. So in the
case of pub-sub mechanism where many subscriber
subscribe to a topic, when does the message get deleted?



Cheers

Re: When is the message deleted in a pub-sub delivery mechanism?

Posted By:   Tom_Jenkinson  
Posted On:   Monday, January 27, 2003 04:38 AM


Conceptually, the message will get deleted after all
subscribers have consumed and acknowledged the message.

However, some JMS vendors will provide administrative (non-
specification) API's to allow an administrator to force
the deletion of messages from a topic. This feature is
perhaps provided to allow for the problem of rogue durable-
subscribers.

As the provider cannot delete (or forget) about a message
for a durable subscriber, then if that durable subscriber
goes offline for a long time, messages for this consumer
should be stored indefinitely. This is not practical as it
would require machines with huge amounts of resources to
handle durable subscribers that were offline for
arbitrarily long times. Therefore the messages can often
be administratively deleted.

Tom Jenkinson
Arjuna Technologies Limited
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