We are experiencing relatively random situation when the messages which are sent to the particular queues ending up as Messages Pending. The only way to solve the problem is to restart an associated Managed Server where an MDB is deployed. There are no Errors/Exceptions in the Managed Server log files. In the Admin Console of the WebLogic we can see that there are "stuck threads" in the Managed Server where we have MDB. What's even more strange is the fact that despite having a lot of messages pending an MDB continues to listen to the Queue and process the messages which arrive later.
Is there any way to resolve the issue without restarting Managed Server?
My suggestion to you is to go on server -> Monitoring -> Threads
You will see a list of threads currently running on your managed server. Look for the threads marked as stuck or hogging and jot down their numbers..
Then, click on Thread Dump on top of the page and look for the stack with the number of your thread... You will see exactly which method is holding your thread and hogging your MDB.
Hope it helps !!!
Related
My application is spring boot micro service listening to a Rabbit MQ queue.
The queue receives messages from different sources.
The requirement is that when the application server is going down (this could happen because of many reasons, may be because we brought the site down, or we are deploying an updated software on to our application server) we would like the queue to process the current message. As of now, we lose the message that the queue is currently processing.
How can I achieve this?
The default shutdownTimeout is 5000ms; you can increase it.
You should not, however, lose any messages, it should be requeued (unless you are using AcknowledgeMode.NONE (which is generally a bad idea).
What are the best practices regarding sessions in an application that is designed to fetch messages from a MQ server every 5 seconds?
Should I keep one session open for the whole time (could be weeks or longer), or better open a session, fetch the messages, and then close the session again?
I am using the .net IBM XMS v8 client library.
Adding to what #Attila Repasi's response, I would go for a consumer with message listener attached. The message listener would get called whenever a message needs to be delivered to application. This avoids application explicitly calling receive() to retrieve messages from queue and waste CPU cycles if there are no messages on the queue.
Check the XMS.NET best practices
Keep the connection and session open for a longer period if your application sends or receive message continuously. Creation of connection or session is a time consuming operation and consumes lot of resources and involves network flow (for client connections).
I'm not sure what you are calling a session, but typically applications connect to the queue manager serving them once at start, and keep that connection up while running.
I don't see a reason to disconnect just to reconnect 5 seconds later.
As for keeping the queues open, it depends on your environment.
If there are no special circumstances, I would keep the queue open.
I think the most worth thinking about is how you issue the GETs to read the messages.
I has some strange behaviour on production deployment for azure queue messages:
Some of the messages in queues appears with big delay - minutes, and sometimes 10 minutes.
Befere you ask about setting delayTimeout when we put message to queue - we do not set delayTimeout for that message, so message should appear almost immedeatly after it was placed in queue.
At that moments we do not have a big load. So my instances has no work load, and able to process message fast, but they just don't appear.
Our service process millions of messages per month, we able to identify that 10-50 messages processed with very big delay, by that we fail SLA in front of our customers.
Does anyone have any idea what can be reason?
How to overcome?
Did anyone faced similar issues?
Some general ideas for troubleshooting:
Are you certain that the message was queued up for processing - ie the queue.addmessage operation returned successfully and then you are waiting 10 minutes - meaning you can rule out any client side retry policies etc as being the cause of the problem.
Is there any chance that the time calculation could be subject to some kind of clock skew problems. eg - if one of the worker roles pulling messages has its close out of sync with the other worker roles you could see this.
Is it possible that in the situations where the message is appearing to be delayed that a worker role responsible for pulling the messages is actually failing or crashing. If the client calls GetMessage but does not respond with an appropriate acknowledgement within the time specified by the invisibilityTimeout setting then the message will become visible again as the Queue Service assumes the client did not process the message. You could tell if this was a contributing factor by looking at the dequeue count on these messages that are taking longer. More information can be found here: http://msdn.microsoft.com/en-us/library/dd179474.aspx.
Is it possible that the number of workers you have pulling items from the queue is insufficient at certain times of the day and the delays are simply caused by the queue being populated faster than you can pull messages from the queue.
Have you enabled logging for queues and then looked to see if you can find the specific operations (look at e2elatency and serverlatency).
http://blogs.msdn.com/b/windowsazurestorage/archive/tags/analytics+2d00+logging+_2600_amp_3b00_+metrics/. You should also enable client logging and try to determine if the client is having connectivity problems and the retry logic is possibly kicking in.
And finally if none of these appear to help can you please send me the server logs (and ideally the client side logs as well) along with your account information (no passwords) to JAHOGG at Microsoft dot com.
Jason
Azure Service bus has a property in the BrokeredMessage class called ScheduledEnqueueTimeUtc, it allows you to set a time for when the message is added to the queue (effectively creating a delay).
Are you sure that in your code your not setting this property, and this might be the cause for the delay?
You can find more info on this at this url: https://www.amido.com/azure-service-bus-how-to-delay-a-message-being-sent-to-the-queue/
If you are using WebJobs to process messages from the queue, it can be due to WebJobs configuration.
From an MSDN forum post by pranav rastogi:
Starting with 0.4.0-beta, the (WebJobs) SDK implements a random exponential back-off algorithm. As a result of this if there are no messages on the queue, the SDK will back off and start polling less frequently.
The following setting allows you to configure this behavior.
MaxPollingInterval for when a queue remains empty, the longest period of time to wait before checking for a message to. Default is 10min.
static void Main()
{
JobHostConfiguration config = new JobHostConfiguration();
config.Queues.MaxPollingInterval = TimeSpan.FromMinutes(1);
JobHost host = new JobHost(config);
host.RunAndBlock();
}
We are using IBM MQ and we are facing some serious problems regarding controlling its asynchronous delivery to its recipient.We are having some java listeners configured, now the problem is that we need to control the messages coming towards listener, because the messages coming to server are in millions count and server machine dont have that much capacity t process so many threads at a time, so is there any way like throttling on IBM MQ side where we can configure preetch limit like Apache MQ does?
or is there any other way to achieve this?
Currently we are closing connection with IBM MQ when some X limit has reached on listener, but doesen't seems to be efficient way.
Please guys help us out to solve this issue.
Generally with message queueing technologies like MQ the point of the queue is that the sender is decoupled from the receiver. If you're having trouble with message volumes then the answer is to let them queue up on the receiver queue and process them as best you can, not to throttle the sender.
The obvious answer is to limit the maximum number of threads that your listeners are allowed to take up. I'm assuming you're using some sort of MQ threadpool? What platform are you using that provides unlimited listener threads?
From your description, it almost sounds like you have some process running that - as soon as it detects a message in the queue - it reads the message, starts up a new thread and goes back and looks at the queue again. This is the WRONG approach.
You should have a defined number of process threads running (start with one and scale up as required, and within limits of your server) which read from the queue themselves. They would each open the queue in shared mode and either get-with-wait or do immediate get with a sleep if you get a MQRC 2033 (no messages in queue).
Hope that helps.
If you are running in the application server environment, then the maxPoolDepth property on the activationSpec will define the maximum ServerSessionPool size for the MDB - decreasing this will throttle the number messages being delivered concurrently.
Of course, if your MDB (or javax.jms.MessageListener in the JSE environment) does nothing but hand the message to something else (or, worse, just spawn an unmanaged Thread and start it) onMessage will spin rapidly and you can still encounter problems. So in that case you need to limit other resources too, e.g. via threadpool configuration.
Closing the connection to the QM is never an efficient way, as the MQCONN/MQDISC cycle is expensive.
I have an application which tries to subscribes to a lot of different topics.
The server side publishes a lot of messages through these topics and as soon as the application starts subscribing, it receives so many messages that the application cannot even reach the end of the subscription function.
It seems that the OnMessage Listener is flooded so much (the listener is the class which is trying to subscribe itself ot all the topics).
So basically is there a way to stop the reception of messages until I have subscribed to all of the topics? Or am I missing something there?
The thread trying to subsscribe to all of the topics never get the processor again.
(If the server is down, the subscription is fine since it does not receive anything so it does not lose the processing power..)
Thank you in advance.
Paul.
You could try lower the prefetch limit of the consumers, this would prevent the broker from attempting to dispatch so many messages when they are created which should help reduce the flooding issue you are seeing.
Here's some documentation that might help.
http://activemq.apache.org/what-is-the-prefetch-limit-for.html
Tim -
www.fusesource.com