I have thousands of messages in an SQS queue, and well under the concurrency limit, but the consumer (a lambda function) is not increasing its concurrency to handle the messages. Anyone know why? The function has not been throlled at all according to the dashboard

Do you know how long the messages are sitting in the queue? quite a while it would seem? Check your

maxRecordAge

setting

Just expanding on Jarod’s point, a couple of parameters you can try tweaking and see if they make a difference. Here’s a code snippet for v1 construct.

new Queue(stack, "Queue", {
  cdk: {
    queue: {
      receiveMessageWaitTime: Duration.seconds(0),
    }
  },
  consumer: {
    function: "src/function.handler",
    cdk: {
      eventSource: {
        batchSize: 10,
        maxBatchingWindow: Duration.minutes(0),
      }
    }
  }
});

Thanks for the input folks - I have all of the above settings on already actually. One thing is that the number of messages not visible was 120000. Do messages not visible count as "in flight"? If so I think that might be it because the max allowed messages in flight is 120k