I have several jobs that each have multiple messages queued.
The messages for each job are randomly interleaved.
If a user decides to cancel a job I want to remove all the messages that are part of that job from the queue.
I have been able to use browse()to find all the messages to remove but haven't been able to figure out how to remove them.
I tried getting rid of them by using receiveSelected() but it just hangs.
(I am using JmsTemplate)
JMS does not define administration type functions, such as deleting a message from the queue.
The programmatic way is to consume the message. Alternatively, there are messaging management tools that allow you to do this without programming.
There is no any JMS API to remove message. However seems you can invoke purge removeMessage or other operation as per your requirement on MBean org.apache.activemq:type=Broker,brokerName=amq,destinationType=Queue,destinationName=testQ to delete messages.
You are on the right track. Consuming those messages using a selector is the way to go - such as with JmsTemplate receiveSelected.
If it "hangs", it likely means you have no matching messages on the queue. Can you identify your messages on some Property, such as JMSType or other StringProperty? Make sure you can and supply a JMS Selector.
I.e. if your jobs are initiated by user X, then set some property such as "initiatingUser" to "x". Then to consume all messages, use the selector initiatingUser='X'.
Related
I have an ActiveMQ messaging system and i want to delete only some scheduled messages from the queue.
I can delete all the scheduled message via a ScheduledMessage.AMQ_SCHEDULER_ACTION_REMOVEALL
message sent to the queue.
I can delete a message by ID by sending a AMQ_SCHEDULER_ACTION_REMOVE message.
But is there a way to delete all messages with a selector (maybe a property on the message) ?
I checked the Jolokia REST API of ActiveMQ, but it seems that informations on Scheduled messages are not available.
No that functionality is not currently supported. You would need to take a look at the source code and implement this yourself and then contribute it back to the community. There is a fine line though were trying to use a message broker as a database will turn around and bite you so I'd recommend caution on that front.
You'd need to implement a new remove directive like AMQ_SCHEDULER_ACTION_REMOVE_SELECTED and define how the selector works in that case, SQL92 string etc and then add an API on the Scheduler store interface and implement it in the Scheduler implementation in the KahaDB module.
Is it possible to keep a history of messages (with message content would be perfect) that have already been retrieved and are no longer on a queue?
In the application I can see when the sender attempts to put the message in the queue and when the receiver attempts to pick the messages up, but I'd like to see when the message really arrived into the queue and when the messages were really received.
Does MQ Explorer have this function? How would I use it?
What you are looking for is a message tracking/auditing software for IBM MQ. You can find a list of what is available here.
It is possible to use an API exit to make copies of messages in a queue or to audit both PUT and GET operations.
It is also possible to put messages to a topic, then create as many administrative subscriptions to destination queues as required. Something can then GET and log messages from one of those destination queues. The problem with this is that MQ changes the message ID between publication and consumption whereas in a queue it remains static.
There is no native MQ function to capture messages. It's possible to use linear logs and later scrape the logs but these do not necessarily capture all messages due to optimization. (A message PUT to a waiting getter outside of syncpoint for example.) However there is at least one commercial product to scrape linear transaction logs to audit message activity.
The philosophy of MQ in general is that it is the delivery mechanism and deals with envelope data to route and deliver but does not deal with payload data. WAS, IIB and other broker/transformation engines are where IBM has put all of the functions that deal with message payloads.
I have got started with ActiveMQ and able to move forward, but I am not able to figure out how I can view all messages that are sent to a particular queue.
I can see the message in the queue as long as it is not consumed by a consumer but as soon as it is consumed by a consumer, I can no longer see the message in the queue.
In my project I used to use "MQJ Explorer" and connect with a queue manager and there I could view all the messages that were sent to a particular queue, so I am expecting similar thing with ActiveMQ.
I know while sending I can have the message marked as "persistent" but still it will be there in the queue only till it is not consumed, once it is consumed I cannot see it any more.
Please let me know if things work differently with ActiveMQ.
The Queue holds messages until they are consumed at which point they are discarded. So you cannot browse all messages that were sent to the queue and then consumed. The only solution to this would be to use a Camel route or similar to mirror the Queue to some other Audit type Queue but you'd need to use a lot of care as this could easily lead to filling the message store as the mirrored messages will continue to grow and take space unless they are purged periodically.
I have a dead-letter queue which stores failed messages. Is there have a way to manually trigger a listener to process the messages in the dead-letter queue? I’m using Spring AMQP.
Like I said, it depends on your use case, but I can assume you are looking for something from spring amqp out-of-the-box.
just have a look at BlockingQueueConsumer, you can i.e. prefetch one message if you want, then start it manually.
Please be aware that you need choose solution according to your case, maybe you just need a flag in db to mark the job is failed, or save the msg in db.
I was wondering if there is a way for you to configure a queue to automatically clear messages? We are striving to partially implement a component of our architecture and want to be able to send to the queue, but have the queue automatically remove the messages that are being sent so that we don't have to run scripts, etc to perform the clean-up.
So far the only thing I have been able to find is to run CLEAR QLOCAL or set the messages to expire from the publishing application.
For you use case there are a few options in IBM MQ:
Create a QALIAS that points to a TOPIC object which has a topic string with no subscribers, messages put to the QA will just disappear.
Have the sending application set message expiry.
Use the IBM MQ CAPEXPRY feature to administratively force message expiry at the queue level.
Run a script to issue CLEAR QLOCAL against the queue. There can not be open handles on the queue for this to work.
Programmatically issue the equivalent PCF command to CLEAR QLOCAL against the queue. There cannot be open handles on the queue for this to work.
Run the IBM MQ dmpmqmsg utility against the queue to read and discard the messages.