Support for SQS Messages up to 1 MiB

[jdaigle]

Describe the feature.

Describe the requested feature

AWS has recently increased maximum message payload size to 1 MiB. We can adjust the algorithm for determining when to offload the message to S3 to support the large message sized.

However, at least as of now, it appears that SNS still has the same 256 KiB limit.

More information here: https://aws.amazon.com/about-aws/whats-new/2025/08/amazon-sqs-max-payload-size-1mib/

Additional Context

No response

[mauroservienti]

Thanks for raising this, @jdaigle.

If SNS is still limited to 256 KiB, that might complicate things a bit. It's also worth mentioning that the message size limit might also have an impact on the transport batching logic.

[jdaigle]

@mauroservienti

If SNS is still limited to 256 KiB, that might complicate things a bit.

I agree. But it seems plausible that AWS might change the limit for SNS in the relative near future too. We can keep a watch out for that.

[mauroservienti]

But it seems plausible that AWS might change the limit for SNS in the relative near future too

Agreed.

[danielmarbach]

From the perspective of the transport it might be possible to split the limits into unicast (sends) and multicast (publish) operations. We are already distinguishing those different flavours today and could therefore loosen the constraints on the unicast path where only SQS is involved. It would definitely complicate slightly the internally logic of the transport but not in unmaintainable ways