SQS short and long polling

• By default, queues use short polling.

• Short polling:

  • ReceiveMessage request queries only a subset of the servers (based on a weighted random distribution) to find messages that are available to include in the response.

  • Sends the response right away, even if the query found no messages.

• Long polling:

  • ReceiveMessage request queries all of the servers for messages

  • Sends a response after it collects at least one available message, up to the maximum number of messages specified in the request.

  • When the wait time for the ReceiveMessage API action is greater than 0.

  • Helps reduce the cost of using SQS by eliminating the number of empty responses and false empty responses.