[roshanj]

> Of course it's possible to solve. But I think the solutions (and the cons of those solutions) are often pretty arduous or unreasonable.

> worst of all, you don't have any transactional consistency across those joins, it's possible to join when you've only consumed one half of the streaming data (e.g. one of two topics).

This is exactly right! Most streaming solutions out there overly simplify real use-cases where you have multiple upstream tables and need strongly consistent joins in the streamed data, such that transactional guarantees are propagated downstream. It's very hard to achieve this with classic CDC + Kafka style systems.

We provide these guarantees in the product I work on and one of our co-founders talks a bit about the benefits here: https://materialize.com/blog/operational-consistency/ .

It's often something that folks overlook when choosing a streaming system and then get bitten when they realize they can't easily join across the tables ingested from their upstream db and get correct results.