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MDB Durable subscription

 
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Hi All,
EJB spec Page 314, topic 15.4 states that-
Durable topic subscriptions, as well as queues, ensure that messages are not missed even if the EJB
server is not running.

How is this possible? If the server is not running, then even the JMS message service is down. Then who will
receive the message sent by the message producer/publisher? In HFE, page 450, says that-
Topic subscriber can request a durable subscription if he wants to make sure that he sees all messages
including the one that accumulated while he was offline

I think this meaning of durable subscription makes sense than in EJB spec. Can some body clarify this?
 
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If the message producer uses "store and forward", the message producer is able to spool the messages to the local store until the MOM (your JMS server) is reactivated (server is started again).
Another thing that can be down is the consumer; the specific EJB server containing the consumer can be down, and the MOM persist the messages until the consumer is up again.
More information can be found from Internet or from "Mastering EJB 2", page 204.

Originally posted by Rashmi Tambe:
Hi All,
EJB spec Page 314, topic 15.4 states that-
Durable topic subscriptions, as well as queues, ensure that messages are not missed even if the EJB
server is not running.

How is this possible? If the server is not running, then even the JMS message service is down. Then who will
receive the message sent by the message producer/publisher? In HFE, page 450, says that-
Topic subscriber can request a durable subscription if he wants to make sure that he sees all messages
including the one that accumulated while he was offline

I think this meaning of durable subscription makes sense than in EJB spec. Can some body clarify this?

 
Rashmi Tambe
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Posts: 418
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thanks Janne!
 
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