messageGroupId

MessageGroupId is an attribute used in Amazon SQS FIFO (First-In-First-Out) and standard queues. In FIFO queues, MessageGroupId organizes messages into distinct groups. Messages within the same message group are always processed one at a time, in strict order, ensuring that no two messages from the same group are processed simultaneously. In standard queues, using MessageGroupId enables fair queues. It is used to identify the tenant a message belongs to, helping maintain consistent message dwell time across all tenants during noisy neighbor events. Unlike FIFO queues, messages with the same MessageGroupId can be processed in parallel, maintaining the high throughput of standard queues.

• FIFO queues:MessageGroupId acts as the tag that specifies that a message belongs to a specific message group. Messages that belong to the same message group are processed in a FIFO manner (however, messages in different message groups might be processed out of order). To interleave multiple ordered streams within a single queue, use MessageGroupId values (for example, session data for multiple users). In this scenario, multiple consumers can process the queue, but the session data of each user is processed in a FIFO fashion.If you do not provide a MessageGroupId when sending a message to a FIFO queue, the action fails.ReceiveMessage might return messages with multiple MessageGroupId values. For each MessageGroupId, the messages are sorted by time sent.

• **Standard queues:**Use MessageGroupId in standard queues to enable fair queues. The MessageGroupId identifies the tenant a message belongs to. A tenant can be any entity that shares a queue with others, such as your customer, a client application, or a request type. When one tenant sends a disproportionately large volume of messages or has messages that require longer processing time, fair queues ensure other tenants' messages maintain low dwell time. This preserves quality of service for all tenants while maintaining the scalability and throughput of standard queues. We recommend that you include a MessageGroupId in all messages when using fair queues.

The length of MessageGroupId is 128 characters. Valid values: alphanumeric characters and punctuation (!"#$%&'()*+,-./:;<=>?@[\]^_{|}~)`.

For best practices of using MessageGroupId, see Using the MessageGroupId Property in the Amazon SQS Developer Guide.