Camel AWS SQS and concurrentConsumers

[Arnaud Level]

Hi,

(Camel version: camel-aws2-sqs-starter: 3.12.0)

I am trying to use and understand concurentConsumers with a SQS queue:

from("aws2-sqs://queuexxx?concurrentConsumers=5&amazonSQSClient=#sqsClient&
waitTimeSeconds=20")
                .process(exchange -> {
                    System.out.println("Message received...");
                    })
                .process(exchange -> {
                    try {
                        Thread.sleep(5000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }});

With the above queue, if I send 3 messages at the same time, I have to wait
5 seconds to see the second message ("Message received...") and 5 more
seconds to see the third one. My understanding of concurentConsumers is
that with a value of 5 I would see the 3 messages at the same time since 3
threads will consume them in parallel. If I add the Thread.sleep in a seda
route, I'm having this behavior (= The 3 messages are read at the same
time).

Turning on the Camel logs it seems that the next polling is done only after
the Delete for the previous message is sent (which is with a delay of 5s).

I would understand the above behavior with concurentConsumers=1 but I don't
with concurentConsumers=5. Could someone tell me what I've misunderstood ?

Thank you in advance!
Arnaud