ActiveMQ message content is not cleared after the message is sent - java

I have java application in which there are a sender and receiver and ActiveMQ Queue
the sender creates messages and sends them to the Queue and the consumer consumes the messages from there.
each time I send a message it gets serialized and its content holds ByteSequence of the message , and the Queue gets that message and the consumer consumes it but, I found that each time I send a message to the Queue, the ByteSequence is not cleared from the memory and eventually I get OutOfMemoryException
shouldn't the message be deleted from the producer after it has been sent to the Queue?
thanks!

well it appears that the Q is using the prefetch default value of 1000 which caused the consumer to get OOM exception because the processing time of each message was too long and the prefetch was only getting filled quickly

Related

Message getting redelivered to RabbitMQ consumer setup using spring cloud stream

We have a SpringBoot service implementation in which we are using delayed messaging with the below setup:
Initial queue (Queue 1) that gets the message has a TTL set, the queue also has a dead letter exchange mentioned with a specific dead letter routing key.
Another queue (Queue 2) is bound to the DLX of the previous queue with the routing key which is set as the dead letter routing key
A consumer listens to the messages on Queue 2.
The delayed messaging seems to work as expected but I am seeing an issue with messages getting redelivered in certain scenarios.
If I have a debug point in my consumer and keep the message just after reading it for some time then once the current message has been processed consumer gets another message which has the below properties:
Redelivered property as true.
Property deliveryAttempt as 1
Only the first message has an x-death header and redelivered messages do not seem to have it.
The attempt to deliver the message is done 3 times as many times as I pause the consumer using the debug point each time after reading each redelivered message.
My understanding was that the acknowledgment mode by default is AUTO so once the consumer has read the message then it would not be redelivered?
I have tried using maxAttempts=1 property but does not seem to help.
I am using the spring cloud stream to create the consumers and the queues.
I used to run into this issue when the message processing in the consumer failed (exception thrown). In this case, if you have DLQ configured, make sure to add the following configuration as well so the failed message will be routed to the DLQ not the original listening queue.
"
rabbit:
autoBindDlq: true
"
Otherwise if you don't set up the DLQ, configure "autoBindDlq" to "false".

JMS send same message back to SQS

I am working on an approach where i am required to send a message back to SQS.
I don't want it to go as a new message as that will reset the approximateRecieveCount parameter which is required by the code.
Please note that
I cannot send a NACK to the queue as i am reading it as a batch of 10 messages, I want to manually post it back in certain cases for individual message and not as a batch.
The code I am trying to use
I tried setting the JMSMessageId but it is not possible as according to the documentation -
After you send messages, Amazon SQS sets the following headers and properties for each message:
JMSMessageID
JMS_SQS_SequenceNumber (only for FIFO queues)
The code i am using right now is
defaultJmsTemplate.send(destinationName, new MessageCreator() {
#Override
public Message createMessage(Session session) throws JMSException {
Message message = session.createTextMessage(errorMessage);
message.setJMSCorrelationID(transactionId);
if (destinationName.endsWith(".fifo")) {
message.setStringProperty("JMSXGroupID", property.getMessageGroup());
message.setStringProperty("JMS_SQS_DeduplicationId", java.util.UUID.randomUUID().toString());
}
return message;
}
});
}
Is there anything that i can set/use to make sure the message is not treated as a new message and the approximate receive count is maintained?
Yes. This can be done. As you are using JMS for SQS while setting up your consumer you can define an UNORDERED_ACKNOWLEDGE mode in your consumer session. By doing so if you do not acknowledge a particular message it will be redelivered after its visibility timeout expires and the approximateRecieveCount will be incremented. This will not impact your other messages in the same batch. One downside of this is if you are using the fifo queue and the all your messages have same group id then you next message will only be processed after this unacknowledged message ends up in dead letter queue. This will only happen after your message is retried for the Maximum Receives that you have set up in fifo queue configuration. Note : The key here is to not acknowledge a particular message.

RabbitMQ receiver need to check for new message in queue

I am using spring and Hibernate with RabbitMQ.
I am facing problem that when sender send message to receiver(consumer) that time message add to queue successfully but receiver have to check every time to get new message from queue.
This is increasing overhead.
Is there any proper solution using that receiver automatic knows that new message in a queue.

RabbitMQ basic.get and acknowledgement

I'm invoking:
GetResponse response = channel.basicGet("some.queue", false); // no auto-ack
....
channel.basicAck(deliveryTag, ...);
However, when I invoke basicGet, the messages in the queue stay in "Ready", rather than in "Unacknowledged". I want them to be in unacknowledged, so that I can either basic.ack them (thus discarding them from the queue), or basic.nack them
I'm doing the following to mimic Delaying the ack:
At consumption time
Get(consume) the message form the initial Queue.
Create a "PendingAck_123456" Queue.
123456 is a unique id of the message.
Set the following properties
x-message-ttl (to requeue after
timeout)
x-expires (to make sure the temp queue will be deleted)
x-dead-letter-exchange and x-deal-letter-routing-key to requeue to
the initial Queue upon TTL expiration.
Publish the message Pending ack to this "PendingAck_123456" Queue
Ack the message to delete it from the initial queue
At Acknowledge time
Calculate Queue Name from Message Id and Get from the "PendingAck_123456" Queue
Acknowledge it (no need to call .getBody() ).
That'll delete it from this pending queue, preventing the TTL to requeue it
Remarks
A Queue for only 1 message.. Is that an issue if there are a lot of such Queues ?
A requeued message will be sent at the queue input side.. not at the queue output (as would do a real ack).. There is an impact on the messages order.
Message is copied by the application to the Pending Queue.. This is an additional step that may have impacts on the overall performance.
To mimic a Nack/Reject, you you may want to Copy the message to the Initial Queue, and Ack it from the PendingAck queue. By default, the TTL would do it (later).
When doing ack immediately after the get it works fine. However, in my case, they were separated by a request. And spring's template closes the channel and connection on each execution. So there are three options:
keep one channel and connection open throughout the whole lifetime of the application
have some kind of conversation-scope (or worst-case: use the session) to store the same channel and reuse it.
use one channel per request, acknowledge receipt immediately, and store the messages in memory.
In the former two cases you can't do it with spring's RabbitTemplate

Acknowledge a message from a different Channel/Session in JMS

I need a message to be Acknowledged in a different Session than the one it is created in. If the consumed message is not ACKed in a given time, it should be added back to the queue. Is this possible using JMS( planning to use ActiveMQ as the broker).
I don't think it is possible.
If the message is consumed, it should be acknowledged by the consumer session (it can be auto or client acknowledgement). Acknowledgment is the key for guaranteed messaging and transaction mechanism. JMS server ensures the message is sent/consumed successfully using acknowledgement.
Regarding timeout question, if the JMS server didn't receive the ack in given time period, the message will be redelivered usually with JMSRedelivered flag set. I don't think it will be added back to the Queue then able to be consumed by same session or another session as a new message.

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