Is ActiveMQQueue really a Queue?
hi ActiveMQ users I'm new to ActiveMQ (bet you never heard that before :-)). I'm using org.apache.activemq.command.ActiveMQQueue as my destination. For debugging purposes I log the events of sending the message and the events of MessageListener.onMessage. I find that... The ActiveMQQueue does not seem to act as a queue - in the "first in, first out" sense. Is that so? Is it configurable? Why do I care? Because it looks as some messages can wait in the queue forever, can be forgotten there. And though it's not exactly my case, some might want a pure FIFO queue implementation. thanks for any help and clarification. -- View this message in context: http://www.nabble.com/Is-ActiveMQQueue-really-a-Queue--tp25625177p25625177.html Sent from the ActiveMQ - User mailing list archive at Nabble.com.
Maintaining Message Uniqueness in a Queue
hi AMQ users What is the best way to ensure Message Uniqueness in a Queue? I'm having the following architecture: A single Scheduler (a quartz scheduled job) is periodically checking a DB for entities to update, for each entity-to-update it uses a single Sender to send an Update Message with a property holding the entity ID. The Sender references an ActiveMQQueue destination and a Spring's JmsTemplate over a PooledConnectionFactory. The Consumers - MessageListeners in a Spring's DefaultMessageListenerContainer container - receive a message and do their onMessage, which may involves updating the DB. I wish to avoid more then one Consumer updating the same entity simultaneously, as it will result in DB errors. I thought the Scheduler should account for this synchronization, so upon resolution of the entities to update, it tags them in order to know not to update them again - a tag that is removed when update is finished. But as errors may occur, this tag is taken in account only for a certain period of time. This makes the situation, in which the queue contains two messages with the same entity ID, possible. Which may cause exactly what I'm trying to avoid. How do I pull it off? I thought knowing which messages are currently in the queue could help the Scheduler decide. What about the message ID? Can it help here? I could also expire the message, but it is not accurate. I might throw away messages for no good reason. Maybe it is better to do this synchronization elsewhere? Thanks a lot for any help or thoughts. -- View this message in context: http://www.nabble.com/Maintaining-Message-Uniqueness-in-a-Queue-tp25660461p25660461.html Sent from the ActiveMQ - User mailing list archive at Nabble.com.
Re: Is ActiveMQQueue really a strict FIFO queue?
The first step of solving a problem is asking the right question. (or is it acknowledging it, and the right question is only the second? :confused:) I was looking for something else. Thanks a lot for all the repliers. Your help did not go unappreciated. Please bare with me to the following thread: http://www.nabble.com/Maintaining-Message-Uniqueness-in-a-Queue-td25660461.html Maintaining Message Uniqueness in a Queue . Thanks. -- View this message in context: http://www.nabble.com/Is-ActiveMQQueue-really-a-Queue--tp25625177p25660661.html Sent from the ActiveMQ - User mailing list archive at Nabble.com.
Re: Maintaining Message Uniqueness in a Queue
As the documentation declares: "Message Groups rock!" It looks like the right thing for me, though I still have to wait for version 5.3. I can do that. Thanks a lot! -- View this message in context: http://www.nabble.com/Maintaining-Message-Uniqueness-in-a-Queue-tp25660461p25665844.html Sent from the ActiveMQ - User mailing list archive at Nabble.com.
Making sure a message was consumed (client acknowledge, time to live)
hi all, I'm looking for a way to verify that a message was consumed, in a given time(!), and to react to a situation when the message was not consumed in that time. I'm setting the destination with CLIENT_ACKNOWLEDGE, and the message with my TimeToLive value. What I need is some listener on the session's event of expiring a message, resulted from a TimeToLive timeout. I did not find any documentation for such a thing. As far as I know, when TimeToLive is reached, the session just kill and drop the message. Does anyone know something else? listening to a message's timeout? 10x Itamara -- View this message in context: http://activemq.2283324.n4.nabble.com/Making-sure-a-message-was-consumed-client-acknowledge-time-to-live-tp2970107p2970107.html Sent from the ActiveMQ - User mailing list archive at Nabble.com.
