FIFO queue and message identifiers in Amazon SQS
This section describes the identifiers of FIFO queues. These identifiers can help you find and manipulate specific queues and messages.
Identifiers for FIFO queues in Amazon SQS
For more information about the following identifiers, see the Amazon Simple Queue Service API Reference.
Queue name and URL
When you create a new queue, you must specify a queue name unique for your Amazon account and region. Amazon SQS assigns each queue you create an identifier called a queue URL that includes the queue name and other Amazon SQS components. Whenever you want to perform an action on a queue, you provide its queue URL.
The name of a FIFO queue must end with the .fifo suffix. The suffix counts towards the 80-character queue name quota.
To determine whether a queue is FIFO, you can check whether the queue name ends with the suffix.
The following is the queue URL for a FIFO queue named MyQueue
owned by a user with the AWS account number
123456789012.
https://sqs.us-east-2.amazonaws.com/123456789012/MyQueue.fifoYou can retrieve the URL of a queue programmatically by listing your queues
and parsing the string that follows the account number. For more information,
see ListQueues.
Message ID
Each message receives a system-assigned message ID that
Amazon SQS returns to you in the SendMessage response. This identifier is useful for
identifying messages. The maximum length of a message ID is 100
characters.
Receipt handle
Every time you receive a message from a queue, you receive a receipt handle for that message. This handle is associated with the action of receiving the message, not with the message itself. To delete the message or to change the message visibility, you must provide the receipt handle (not the message ID). Thus, you must always receive a message before you can delete it (you can't put a message into the queue and then recall it). The maximum length of a receipt handle is 1,024 characters.
Important
If you receive a message more than once, each time you receive it, you get a different receipt handle. You must provide the most recently received receipt handle when you request to delete the message (otherwise, the message might not be deleted).
The following is an example of a receipt handle (broken across three lines).
MbZj6wDWli+JvwwJaBV+3dcjk2YW2vA3+STFFljTM8tJJg6HRG6PYSasuWXPJB+Cw
Lj1FjgXUv1uSj1gUPAWV66FU/WeR4mq2OKpEGYWbnLmpRCJVAyeMjeU5ZBdtcQ+QE
auMZc8ZRv37sIW2iJKq3M9MFx1YvV11A2x/KSbkJ0=Additional identifiers for Amazon SQS FIFO queues
For more information about the following identifiers, see Exactly-once processing in Amazon SQS and the Amazon Simple Queue Service API Reference.
Message deduplication ID
A token used in Amazon SQS FIFO queues to uniquely identify messages and prevent duplication. If multiple messages with the same deduplication ID are sent within a 5 minute deduplication interval, they are treated as duplicates, and only one copy is delivered. If you don't specify a deduplication ID and content-based deduplication is enabled, Amazon SQS generates a deduplication ID by hashing the message body. This mechanism ensures exactly-once delivery by eliminating duplicate messages within the specified time frame.
Message group ID
The tag that specifies that a message belongs to a specific message group. Messages that belong to the same message group are always processed one by one, in a strict order relative to the message group (however, messages that belong to different message groups might be processed out of order).
Sequence number
The large, non-consecutive number that Amazon SQS assigns to each message.