The time, in seconds, to wait for a message to arrive in the queue (long polling). Values can be from 1 to 20. Default is 20.

Larger values reduce the number of requests that need to be sent. It is recommended to use the maximum value. Reduce the value only if you experience issues and are certain that a shorter request timeout fixes them.

See also: Amazon SQS Long Polling
See also: Amazon SQS – Long Polling and Request Batching / Client-Side Buffering