AWS SQS FIFO Queue – Certification


  • SQS FIFO Queue provides enhanced messaging between applications with the additional features
    • FIFO (First-In-First-Out) delivery
      • order in which messages are sent and received is strictly preserved
      • key when the order of operations & events is critical
    • Exactly-once processing
      • a message is delivered once and remains available until a consumer processes and deletes it
      • key when duplicates can’t be tolerated.
      • limited to 300 transactions per second (TPS)
  • FIFO queues provide all the capabilities as Standard queues and improves upon and complements the standard queue.
  • FIFO queues support message groups that allow multiple ordered message groups within a single queue.
  • FIFO queues are available in the US East (N. Virginia), US East (Ohio), US West (Oregon), and EU (Ireland) regions (keeps on changing)
  • FIFO Queue name should end with .fifo
  • SQS Buffered Asynchronous Client doesn’t currently support FIFO queues
  • Not all the AWS Services support FIFO like
    • Auto Scaling Lifecycle Hooks
    • Amazon CloudWatch Events
    • AWS IoT Rule Actions
    • AWS Lambda Dead-Letter Queues
    • Amazon S3 Event Notifications
    • Amazon SNS Topic Subscriptions

Message Deduplication

  • SQS APIs provide deduplication functionality that prevents message producer from sending duplicates.
  • Message deduplication ID is the token used for deduplication of sent messages.
  • If a message with a particular message deduplication ID is sent successfully, any messages sent with the same message deduplication ID are accepted successfully but aren’t delivered during the 5-minute deduplication interval.
  • So basically, any duplicates introduced by the message producer are removed within a 5-minute deduplication interval
  • Message deduplication applies to an entire queue, not to individual message groups

Message groups

  • Messages are grouped into distinct, ordered “bundles” within a FIFO queue
  • Message group ID is the tag that specifies that a message belongs to a specific message group
  • For each message group ID, all messages are sent & received in strict order
  • However, messages with different message group ID values might be sent and received out of order.
  • Every message must be associated with a message group ID, without which the action fails.
  • SQS delivers the messages in the order in which they arrive for processing, if multiple hosts (or different threads on the same host) send messages with the same message group ID

Also Refer Blog Post – SQS Standard Queues vs FIFO Queues

AWS Certification Exam Practice Questions

  • Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
  • Open to further feedback, discussion and correction.

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