SQS Duplicate messages handling

Question

I am running a queue process using Amazons SQS and a separate machine that processes the jobs (a worker). I am also using the supervisor to make sure t

Answer 1

With SQS, once a worker takes an item - it is the worker's responsibility to immediately delete the item from SQS so that other workers will not get the item as well.

This part of the documentation explains what amount of time you are allowed for, to delete the item - http://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/AboutVT.html

Since you did not show the code of your e-mail sending Laravel worker, I can only guess that you are not deleting the SQS item immediately - but instead maybe deleting it only after the e-mail was sent. Should the e-mail sending part take more than SQS Visibility Timeout (described in the link document), it would make sense the same task is picked up by other workers.