I find it a bit weird, that company that created a DynamoDB is now supporting a data store that supposed to be an open source DynamoDB. Does that mean Cassandra is better than DynamoDB since people would still prefer to use Cassandra in AWS?

Hasn't this been amazon's MO the last couple years? Competition with their in-house versions hasn't prevented AWS from building anything before.

It's not really an admission that one is "better" than the other, it's just an admission that people like managed drop-in replacements for tools that they're already using.

As a side note, I'm interested why Facebook doesn't have a cloud offering yet. I'd love to see more players in this space.

Would you really want “sponsored” rows automatically appearing in your Facebook-managed database?

I briefly read through those leaked FB files, I think they're on NBC News. There was an email and other documents that showed they were thinking about opening a cloud offering multiple times, but it seems they never got round to launching it in the end.

Dynamodb the product != the Dynamo paper which Cassy is based off. I was using Cassy in 2011 before Amazon asked me to use big bird which was the code name for DynamoDB.

I struggle to think of any similarities, actually. I think DynamoDB's design makes it clear that the era of decentralized architecture/eventual consistency at Amazon has come and gone. DHTs just don't make sense in the data center.

Can you elaborate on this?

Do you mean that amazon is tending towards strong or externalizable consistency now?

I’ve always noticed AWS products tend towards eventual consistency, and Google Cloud offerings are almost all strongly consistent.

For example S3 is eventually consistent for read after write (if it’s not the first write). Google cloud storage is strongly consistent for read after all writes.

I think the goal is for S3 to "eventually" be strongly consistent. I heard one of S3's designers say that they shouldn't have opted for eventual consistency in retrospect.

Not sure what you mean, DDB provides both strong and eventual consistency, now in 2 fashions with transactions. 3 if you include cross region replication.

There's definitely still a DHT sitting under there.

No, it's something like a hash-partitioned primary-backup-replicated distributed database. S3 is much closer to a DHT.

There's no real difference between a DHT (distributed hash table) and a hash-partitioned distributed database. It's the same concept. Apache Cassandra is considered an implementation of a DHT.

DynamoDB is decentralized same with S3, it's just abstracted from the user.

Naah, I just think it means that people will pay for a hosted Cassandra instance that wouldn’t migrate to DynamoDB.

Honestly having a SaaS and the hosting instances of your competing offerings is probably a good strategy.

There are a lot of libraries and tools that interact with Cassandra. Having an API compatible service solves a lot of problems for companies that are already invested in Cassandra.

Only if it were completely compatible.

As they aren't, even new projects will often not use DynamoDB to avoid vendor lock-in

IMO no. Amazon just offers what people use.

I think Amazon realises that it is better for them to disrupt themselves, rather than someone else.

People use Cassandra. So Amazon is going to provide it.

It doesn't have to be one or the other. They are giving people a choice, and are getting paid either way.

Obligatory I work for Amazon and this is my personal opinion.

As a customer, it's feels way better to have both options like this in AWS, and I'm sure DDB and managed Cassandra will always have pros and cons in standalone functionality and ecosystem integration.

I just left a company that used an in-house cloud object storage product for their cloud DVR service. It was an amazing piece of tech that was hamstrung by some of the most irritating "features" of Cassandra. We spent more time cleaning up than anything else. I am looking forward to seeing how people use this at scale.

Could you provide a bit more specifics on what was being cleaned up please? Thanks