I am looking for a solution for below mentioned problem.
There is JMS Queue which stores message, lets assume messages are m1, m2,...m10k.
When single consumer start consuming messages from the Queue
It need to read 1000 messages at a time (We are using QueueBrowser)
pass m1 to m1k
pass m1001 to m2k..
Looking for some suggestions how it can be achieved.
Related
I am new to Apache Kafka and I am trying to configure Apache Kafka that it receives messages from the producer as much as possible but it only sends to the consumer configured number of messages per specific time.
In other words How to configure Apache Kafka to send only "50 messages for example" per "30 seconds"
to the consumer regardless of the number of the messages, and in the next 30 seconds it takes another 50 messages from the cashed messages and so on.
If you have control over the consumer
You could use max.poll.records property to limit max number of records per poll() method call. And then you only need to ensure that poll() is called once in 30 seconds.
In general you can take a look at all available configuration properties here.
If you cannot control consumer
Then the only option for you is to write messages as per your demand - write at most 50 messages in 30 seconds. There are no configuration options available. Only your application logic can achieve that.
updated - how to control ensure call to poll
The simplest way is to:
while (true) {
consumer.poll()
// .. do your stuff
Thread.sleep(30000);
}
You can make things more complex with measuring time for processing (i.e. starting after poll call up to Thread.sleep() to not wait more then 30 seconds at all.
The problem that producer really doesn't send messages to the consumer. There is that persistent Kafka topic in between where producer places its messages. And it really doesn't care if there is any consumer on the other side. Same from the consumer perspective: it just subscribers for data from the topic and doesn't care if there is some producer on the other side. So, thinking about a back-pressure from the consumer down to producer where there is a messaging middle ware is wrong direction.
On the other hand it is not clear how those consumed messages may impact your third party service. The point is that Kafka consumer is single-threaded per partition. So, all the messages from one partition is going to be (must) processed one by one in the same thread. This way you cannot send more than one messages to your service: the next one can be sent only when the previous has been replied. So, think about it: how it is even possible in your consumer application to excess rate limit?
However if you have enough partitions and high concurrency on the consumer side, so you really may end up with several requests to your service in parallel from different threads. For this purpose I would suggest to take a look into a Rate Limiter pattern. This library provides a good implementation: https://resilience4j.readme.io/docs/ratelimiter. It is much better to keep messages in the topic then try to limit producer somehow.
To conclude: even if the consumer side is not your project, it is better to discuss with that team how to improve their consumer. You did your part well: the producer sends messages to Kafka topic. What else you can do over here?
Interesting use case and not sure why you need it, but two possible solutions: 1. To protect the cluster, you could use quotas, not for amount of messages but for bandwidth throughput: https://kafka.apache.org/documentation/#design_quotas . 2. If you need an exact amount of messages per time frame, you could put a buffering service (rate limiter) in between where you consume and pause, publishing messages to the consumed topic. Rate limiter could consume next 50 then pause until minute passes. This will increase space used on your cluster because of duplicated messages. You also need to be careful of how to pause the consumer, hearbeats need to be sent else you will rebalance your consumer continuously, ie you can't just sleep till next minute. This is obviously if you can't control the end consumer.
I have 2 applications A and B, trying to send messages from both to one queue.
Placed a while loop at both places which is sending message to queue.
if i start application A and start while loop it starts sending message to queue and consumer consumes message sent from A, now at same time if i start while loop from B application it doesn't publish messages to queue as consumer doesn't consumes any message sent from B.
So can someone clear the doubt if messages are being sent at same time from multiple producers to single queue or not.
PS- using IBM queue and using a single consumer.
Yes, we can have multiple producers for single queue.
Multiple producers can also publish messages at the same time.
How to consume bulk (something like prefetchCount = 10) messages in one shot in spring framework of rabbitMq?
Note - I am implementing Consumer not Listener
As of now I'm using
Message message = amqpTemplate.receive("Queue_Name");
But the problem with the above solution is, it fetches only one message in one shot
I'm curious why you want to process 10 at a time. Typically messages are discreet and processed individually. That's why RabbitMQ will only pass a single message to a given instance of a consumer at a time. A PrefetchCount of 10 will call the consumer 10 times, with one message each. If you have to process 10 messages at once for some reason, you would need to receive messages individually, acknowledge each one and store them in a collection as they're received. Then when your count = 10, start processing them.
A case where senders are sending messages to a Queue, for example message1 is sent by sender1 to a queue. Now a consumer named consumer1 connects to queue and reads the message message1.
There is another consumer named consumer2. But the message message1 is already consumed by consumer1 so it will not be available for consumer2.
When a next message arrives in queue, consumer2 might receive that message if it reads the queue before consumer1.
Does it mean that it all is a case whether one consumer reads the queue before the other in order to get the first message available from the queue?
This is the nature of a Queue in JMS, messages are sent to one consumer and once ack'd they are gone, the next consumer can get the next message and so on. This is often referred to as competing consumers or load balancing. The consumers can share the work as jobs or work items are enqueued which allows for higher throughput when the work associated with the items in the Queue can take significant time.
There are options depending on the messaging broker to make a consumer exclusive such that only that consumer can read messages from the queue while the other consumers sit and wait for the exclusive consumer to leave which makes them backups of a sort.
Other options are to use something like Apache Camel to route a given message to more than one queue, or to use AcitveMQ Virtual Topics to send messages to a Topic and have that message then enqueue onto specific consumer Queues.
The solution depends on the broker you are using and the problem you are trying to solve, none of which you've really made clear in the question.
Is there a way (third party software or programming) to monitor the time a message arrive to an specific queue and the time it's consumed?
something like a message arrive at 17:14:22 565 and consumed at 17:14:22 598 or the message was enqueued N miliseconds
I have read about Statistics plugin but it just give max and min times of enqueued messages
You can use http://activemq.apache.org/advisory-message.html
First example below to be notified when a message is delivered to the broker.
Second example to be notified when the message is consumed.
AdvisorySupport.getMessageDeliveredAdvisoryTopic()
AdvisorySupport.getMessageConsumedAdvisoryTopic()
See example here below to have access to Message properties like creation time, in or out time when a messages arrived or left the broker.
Here is the list of properties http://activemq.apache.org/activemq-message-properties.html
Spring JMS Producer and Consumer interaction
One way is to write your own plugin. (http://activemq.apache.org/developing-plugins.html)
It's quite simple, and the effect is similar as you change activemq broker code.
You can extends BrokerFilter class, and override it's methods, like postProcessDispatch(), send(). Then you can record the time, or whatever you want in your own code.
I write a simple example (https://github.com/lcy362/FoxActivemqPlugin/blob/b54d375a6a91a9ec418e779deb69a8b11f7d985a/src/main/java/com/mallow/activemq/FoxBrokerPlugin.java), hoping that's helpful.