zlacker

>>pul+(OP)
Must be something about Kafka to attract these kind of explanations. Another one few months back was a children's book on Kafka [1] . For me it just look like solution looking for actual problems.

I wonder if Kafka represents an existential angst in these Kubernetized Microservice times. Or is it more simply I am just too dumb to learn and use this shit correctly.

1. https://news.ycombinator.com/item?id=27541339

>>geodel+nkb
Sometimes I wonder if I'm the crazy one. Kafka seems to me to be the only sensible foundational datastore out there: it can maintain and propagate a log with all the properties you would want a datastore to have. Relational database seem to be a crazily overengineered solution in search of a problem, with incredibly poor reliability properties (essentially none of them are true master-master HA out of the box, and they tend to require significant compromises to make them so) to boot.

>>lmm+ltb
> Relational database seem to be a crazily overengineered solution in search of a problem

I mean, whoever in their right mind would want to:

- have a snapshot of data

- query data, including ad-hoc querying

- query related data

- have trasactional updates to data

When all you need is an unbounded stream of data that you need to traverse in order to do all these things.

>>dmitri+UAb
> - have a snapshot of data

Being able to see a snapshot is good, and I would hope to see a higher-level abstraction that can offer that on top of something Kafka-like. But making the current state the primary thing is a huge step backwards, especially when you don't get a history at all by default.

> - query data, including ad-hoc querying

OK, fair, ad-hoc queries are one thing that relational databases are legitimately good at. Something that can maintain secondary indicies and do query planning based on them is definitely useful. But you're asking for trouble if you use them in your live dataflow or allow ad-hoc queries to write to your datastore.

> - have trasactional updates to data

I do think this one is genuinely a mistake. What do you do when a transaction fails? All of the answers I've heard imply that you didn't actually need transactions in the first place.

>>lmm+ACb
> But making the current state the primary thing is a huge step backwards

Why?

When is "I need to query all of my log to get the current view of data" is a step forward? All businesses operate on the current view of data.

> OK, fair, ad-hoc queries are one thing that relational databases are legitimately good at.

Not just ad-hoc queries. Any queries.

> But you're asking for trouble if you use them in your live dataflow or allow ad-hoc queries to write to your datastore.

In our "live datafows" etc. we use a pre-determined set of queries that are guaranteed to run multiple orders of magnitude faster in a relational database on the current view of data than having to reconstruct all the data from an unbounded stream of raw events.

> What do you do when a transaction fails?

I roll back the transaction. As simple as that.