Re: [DISCUSS] KIP-647: Add ability to handle late messages in streams-aggregation

2020-08-27 Thread Matthias J. Sax
In general, I like Bruno's proposal. Was also checking how Flink is handling this case, and similar to Bruno's proposal, they have a so-called "side output": https://ci.apache.org/projects/flink/flink-docs-stable/dev/stream/operators/windows.html#getting-late-data-as-a-side-output The only "concer

Re: [DISCUSS] KIP-647: Add ability to handle late messages in streams-aggregation

2020-08-26 Thread Bruno Cadonna
Hi Igor, Thank you for your answers! I think I understand your reasoning. Looking at your proposal, some questions/comments arose. 1. Who would be responsible for the topic to which the late records should be sent? Is it a topic users create and manage or is it an internal topic that is mana

Re: [DISCUSS] KIP-647: Add ability to handle late messages in streams-aggregation

2020-08-25 Thread Igor Piddubnyi
Hi Matthias, Bruno, Let me elaborate on my suggestions regarding late-tick handling. > why you rejected the more general solution involving a callback The main reasons why I tend to the topic approach is API-consistency and cleanness of the user code. The problem with a callback, in my opinion,

Re: [DISCUSS] KIP-647: Add ability to handle late messages in streams-aggregation

2020-08-11 Thread Bruno Cadonna
Hi Igor, Thanks for the KIP! Similar to Matthias, I am also wondering why you rejected the more general solution involving a callback. I also think that writing to a topic is just one of multiple ways to handle late records. For example, one could compute statistics over the late records befo

Re: [DISCUSS] KIP-647: Add ability to handle late messages in streams-aggregation

2020-07-27 Thread Matthias J. Sax
Thanks for the KIP Igor. What you propose sounds a little bit like a "dead-letter-queue" pattern. Thus, I am wondering if we should try to do a built-in "dead-letter-queue" feature that would be general purpose? For example, uses can drop message in the source node if they don't have a valid times