Amazon S3 consistency model for new objects

Question

Looking at https://docs.aws.amazon.com/AmazonS3/latest/dev/Introduction.html,

Amazon S3 provides read-after-write consistency for PUTS of new objects in your S3 bucket in all regions with one caveat. The caveat is that if you make a HEAD or GET request to the key name (to find if the object exists) before creating the object, Amazon S3 provides eventual consistency for read-after-write.

My understanding from this is that if I create a new object and I haven't checked for its existence beforehand, it should be available immediately (e.g., show up in list requests).

But the above link also says

...you might observe the following behaviors:

• A process writes a new object to Amazon S3 and immediately lists keys within its bucket. Until the change is fully propagated, the object might not appear in the list.

which contradicts the first statement as it basically says read-after-write consistency is always eventual for PUTS.

Answer 1

I read it as:

• Amazon guarantees that a ReadObject request (GET and HEAD) will succeed (read-after-write consistency) for any newly PUT object, assuming you haven't requested the object before

• Amazon doesn't guarantee that a ListBucket request will be immediately consistent for any newly PUT object, but rather the new object will eventually show up in a ListBucket request (eventual consistency)

Answer 2

S3 is now strongly consistent, all S3 GET, PUT, and LIST operations, as well as operations that change object tags, ACLs, or metadata, are now strongly consistent. What you write is what you will read, and the results of a LIST will be an accurate reflection of what’s in the bucket. This applies to all existing and new S3 objects, works in all regions, and is available to you at no extra charge! There’s no impact on performance, you can update object hundreds of times per second if you’d like, and there are no global dependencies.

https://aws.amazon.com/blogs/aws/amazon-s3-update-strong-read-after-write-consistency/