1

I want to use a FIFO SQS for message transport - while researching I found the following two statements:

  • Messages per queue: The number of messages that an Amazon SQS queue can store is unlimited.
  • Messages per queue (in flight): For FIFO queues, there can be a maximum of 20,000 inflight messages (received from a queue by a consumer, but not yet deleted from the queue). To avoid reaching the quota, you should delete messages from the queue after they're processed.

It's clear to me that there is a limit of 20k messages when I received the messages but did not yet delete them (so they are in their invisibility timeout).

What happens after the invisibility timeout and receive token expire? Do received, but not deleted messages also count towards this limit - even after a long period of time?

Improve this question

1 Answer 1

Reset to default
1

So I tried it myself and came to the following conclusion:

  • FIFO queues can hold an unlimited amount of messages
  • After peeking 20k messages (that are now considered "in flight"), you don't get any more messages trying to peek other available messages
  • After the receive handle of a in flight message expires, it will be deducted from the "in flight" quota and is considered "available" again
  • The service peeking messages, when the 20k quota is reached, does not get any error message but instead receives an empty message list.
Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .