AWS SQS Why is requests number so high

Question

I have a simple lambda app that is not in production right now, only being used for testing and debugging. The function sends a message to SQS to perform CRUD operations on an external application. I've set this function to be invoked by SQS when it receives a message, so the same function is sending and receiving.

I've just received an email saying I've used over 85% of my free tier SQS requests quota, or over 850,000 requests in just the past 2 weeks. I'm certain these requests are not messages being sent to queue, or received. The number of sends/receives has to be under 1000 for how often I've used this app. I've also verified using SQS monitoring that there are no messages stuck in queue. And the number of sent messages is more or less what I expected, a low number.

Like I said this app is only being used by myself for testing, a few days per week. Where does the 850,000+ requests come from?

Answer 1

Amazon SQS is charged at $0.40 per million API calls. Calls include send, receive and delete, so it is possible that a message might use 3+ API calls.

From AWS Lambda Adds Amazon Simple Queue Service to Supported Event Sources | AWS News Blog:

There are no additional charges for this feature, but because the Lambda service is continuously long-polling the SQS queue the account will be charged for those API calls at the standard SQS pricing rates.

Long-polling takes 20 seconds, which makes 4320 polls per day. This equates to 60,480 over two weeks or 129,600 per month. Admittedly, it would be more if messages are flowing, since long polling exits whenever there are messages.

So, either the queue is being used a lot (and you are getting excellent value for your $0.40) or you have something else generating lots of SQS API calls.