can an aggregation be over two keywords? :window/aggregation [:heating-and-cooling-aggregation [:on :type]]

i could combine those in the segment i think. Something like... {id: a some-key {:status “on” :type “toaster”}} but it might be nice to push less information into the aggregation function (not sure it will matter).

Are segments received by processors in order and at least once, or can they be dropped due to full buffers or received out of order?

@yonatanel Segments will be received at least once.

If you need ordering you can enforce that with windowing

@drankard sorry, I don’t know what that could be

I wonder if I can use Onyx as a CQRS framework with kind of live actors that keep state and get commands and events in order and never miss any. This project uses it but is it correct? https://yuppiechef.github.io/cqrs-server/

That project seems a bit outdated, Onyx offers a better suite of tools now for maintaining event order. To answer you’re question, yes Onyx can support building a CQRS style system.