Changes the visibility timeout of a specified message in a queue to a new value. The default visibility timeout for a message is 30 seconds. The minimum is 0 seconds. The maximum is 12 hours. For more information, see
Visibility Timeout in the
Amazon SQS Developer Guide.
For example, if the default timeout for a queue is 60 seconds, 15 seconds have elapsed since you received the message, and you send a ChangeMessageVisibility call with
VisibilityTimeout set to 10 seconds, the 10 seconds begin to count from the time that you make the
ChangeMessageVisibility call. Thus, any attempt to change the visibility timeout or to delete that message 10 seconds after you initially change the visibility timeout (a total of 25 seconds) might result in an error.
An Amazon SQS message has three basic states:
- Sent to a queue by a producer.
- Received from the queue by a consumer.
- Deleted from the queue.
A message is considered to be
stored after it is sent to a queue by a producer, but not yet received from the queue by a consumer (that is, between states 1 and 2). There is no limit to the number of stored messages. A message is considered to be
in flight after it is received from a queue by a consumer, but not yet deleted from the queue (that is, between states 2 and 3). There is a limit to the number of in flight messages.
Limits that apply to in flight messages are unrelated to the
unlimited number of stored messages.
For most standard queues (depending on queue traffic and message backlog), there can be a maximum of approximately 120,000 in flight messages (received from a queue by a consumer, but not yet deleted from the queue). If you reach this limit, Amazon SQS returns the
OverLimit error message. To avoid reaching the limit, you should delete messages from the queue after they're processed. You can also increase the number of queues you use to process your messages. To request a limit increase,
file a support request.
For FIFO queues, there can be a maximum of 20,000 in flight messages (received from a queue by a consumer, but not yet deleted from the queue). If you reach this limit, Amazon SQS returns no error messages.
If you attempt to set the VisibilityTimeout to a value greater than the maximum time left, Amazon SQS returns an error. Amazon SQS doesn't automatically recalculate and increase the timeout to the maximum remaining time. Unlike with a queue, when you change the visibility timeout for a specific message the timeout value is applied immediately but isn't saved in memory for that message. If you don't delete a message after it is received, the visibility timeout for the message reverts to the original timeout value (not to the value you set using the ChangeMessageVisibility action) the next time the message is received.