Can You Have Multiple Consumers for an SQS FIFO Queue While Preserving Order? скачать в хорошем качестве

Can You Have Multiple Consumers for an SQS FIFO Queue While Preserving Order?

Explore how Amazon SQS FIFO queues manage multiple consumers to maintain message order and ensure single processing. Learn if it's possible for your use case. --- This video is based on the question https://stackoverflow.com/q/77772731/ asked by the user '100ELL' ( https://stackoverflow.com/u/22248071/ ) and on the answer https://stackoverflow.com/a/77772824/ provided by the user 'John Rotenstein' ( https://stackoverflow.com/u/174777/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, comments, revision history etc. For example, the original title of the Question was: Is it possible to have multiple consumers for an SQS FIFO queue, when my use case restricts me to process messages in creation order and only once? Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- Can You Have Multiple Consumers for an SQS FIFO Queue While Preserving Order? In today's software architecture, many organizations are looking to maintain scalability while ensuring reliability. One common use case revolves around Amazon SQS FIFO queues—a solution designed to process messages in a strict order and ensure each message is processed exactly once. However, a question frequently arises: Is it possible to have multiple consumers for an SQS FIFO queue without violating the order of message processing? In this guide, we will delve into this problem and provide a comprehensive answer, breaking down how SQS FIFO queues handle delivery with multiple consumers. Understanding FIFO Queues What is a FIFO Queue? A FIFO (First-In-First-Out) queue ensures that messages are processed in the exact order they are received. This is crucial in scenarios where the sequence of processing impacts outcomes or functionality. How Does SQS FIFO Queue Work? When sending a message to an SQS FIFO queue, the sender must designate a MessageGroupId, which categorizes the messages within the queue. Think of this as grouping messages based on specific identifiers, akin to buses sending their location data at regular intervals. The Role of MessageGroupId When there are multiple consumers trying to receive messages from an SQS FIFO queue, the MessageGroupId plays a vital role. Here’s how: Receiver Mechanism: Consumer-1 requests messages from the queue. SQS will return messages from any bus (or MessageGroupId), potentially serving multiple messages from the same group. Invisible Messages: After Consumer-1 retrieves messages, those messages become ‘invisible’ while being processed. If Consumer-1 fails during processing, those messages will return to the queue. Order Maintenance: If Consumer-2 attempts to request messages while Consumer-1 is processing, SQS will not give Consumer-2 any messages that belong to the MessageGroupId that Consumer-1 is currently handling. This ensures that messages from the same group are processed in the correct order. Mini-Queues Concept You can think of an SQS FIFO queue as containing several 'mini-queues,' each corresponding to a distinct MessageGroupId. While one group's messages are being processed, consumers can continue processing messages from different groups. When One Group is Dominated If your situation involves a single group of messages that must be processed strictly in order, then the behavior changes: In such cases, no subsequent consumers will receive any messages from that specific group until the existing consumer completes processing. This effectively prevents parallel processing for that group, emphasizing that strict ordering will take precedence over concurrency. Conclusion While you can deploy multiple consumers for an SQS FIFO queue, the constraints imposed by MessageGroupId mean that strict message ordering is maintained. If your application requires messages from a single group to be processed sequentially, SQS ensures no other consumer will handle those messages until the current processing is complete. For scenarios where complete parallel processing of messages is necessary while maintaining strict order, you might need to consider alternative architectures. In summary, the combination of FIFO queues and MessageGroupId allows you to have multiple consumers while preserving the order of messages provided you carefully manage group assignments. This makes SQS FIFO queues a powerful tool in designing robust and efficient message-driven architectures.