Amazon SQS FIFO queue key terms
The following key terms can help you better understand the functionality of FIFO queues. For more information, see the Amazon Simple Queue Service API Reference.
- Clients
The Amazon SQS Buffered Asynchronous Client doesn't currently support FIFO queues.
- Message deduplication ID
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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.
Note
Amazon SQS continues to keep track of the message deduplication ID even after the message is received and deleted.
- Message group ID
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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).
- Receive request attempt ID
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The token used for deduplication of
ReceiveMessagecalls. - Sequence number
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The large, non-consecutive number that Amazon SQS assigns to each message.
- Services
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If your application uses multiple AWS services, or a mix of AWS and external services, it is important to understand which service functionality doesn't support FIFO queues.
Some AWS or external services that send notifications to Amazon SQS might not be compatible with FIFO queues, despite allowing you to set a FIFO queue as a target.
The following features of AWS services aren't currently compatible with FIFO queues:
For information about compatibility of other services with FIFO queues, see your service documentation.
