title: AWS SQS - when will the duplicated message arrive?
body: <p>I understand that standard SQS uses &quot;at least once&quot; delivery while FIFO messages are delivered exactly once. I'm trying to weigh standard queues vs FIFO for my application, and one factor is how long it takes for the duplicated message to arrive.</p>
  <p>I intend to consume messages from SQS then post the data I received to an idempotent third-party API. I understand that with standard SQS, there's always a risk of me overwriting more recent data with the old duplicated data.</p>
  <p>For example:</p>
  <pre><code>Message A arrives, I post it onwards.
  Message A duplicate arrives, I post it onwards.
  Message B arrives, I post it onwards.
  All fine ✓
  </code></pre>
  <p>On the other hand:</p>
  <pre><code>Message A arrives, I post it onwards.
  Message B arrives, I post it onwards.
  Message A duplicate arrives - I post it and overwrite the latest data, which was B! ✖
  </code></pre>
  <p>I want to measure this risk, i.e. I want to know how long the duplicate message should take to arrive. Will the duplicate message take roughly the same amount of time to arrive, as the original message?</p>