[taywrobel]

> The broader Kafka ecosystem has features like exactly-once support

No. No it doesn’t. It has at-least-once delivery with client-side deduplication. That’s not new, it’s what TCP does FFS. Why would you lie to people about supporting something long established at best and demonstrably impossible at worst?

> Finally, I work at Confluent....

Oh, that’s why. Never mind then. Continue selling digital snake oil.

[tiew9Vii]

This is one of the differences between Kafka (Confluent) and Pulsar.

Confluent make big bold claims "Exactly once delivery" and have aggressive marketing.

Pulsar on the other hand would say we have "effectivley-once". Reading Pulsar docs vs Kafka, Pulsar are very modest about functionality and have no commercial marketing at all.

These days I have noticed Confluent in blog posts do use effectively once but marketing is as aggressive as ever.

Credit where credit is due. Confluent, the marketing and big bold claims is why almost everyone is using Kafka and not Pulsar and may not of even heard of Pulsar. I do find Pulsar architecture more interesting, since Splunk has brought them though it's remained in the background like it always has with no huge push to sell it.

[lmm]

> No. No it doesn’t. It has at-least-once delivery with client-side deduplication. That’s not new, it’s what TCP does FFS.

It's not just deduplication, you can atomically commit a consumer from one topic + produce of records resulting from that. Which is exactly the same exactly-once guarantee that you get from e.g. an SQL database in linearizable mode (a lot of SQL databases will do the same thing internally - optimistically execute transactions and then re-run them in the case of a conflict).