Dear Daeho Kwon, Thanks for the KIP!
>From my understanding of the JIRA ticket, two proposals were evaluated: - Exposing the DLQ method to PAPI (affects public API). - Creating an internal utility for DSL operators or extending InternalProcessorContext instead of the public one (this still affects the public DLQ API, but avoids changes to PAPI). If we choose to change PAPI, we likely need to extend the scope of the KIP. Currently, it focuses on the DSL, but adding this method to ProcessingContext would enable it for all clients. I suggest revisiting the proposals to consider the trade-offs between using an internal utility for the DSL case versus generally enabling this functionality for PAPI. I also have the following questions regarding the KIP: - bloku1: The "Compatibility, Deprecation, and Migration Plan" section states there are no changes to the public API, but adding a method to ProcessingContext seems to contradict this. Can we clarify this point? - bloku2: What happens if a user calls the writeToDlq method without specifying a DLQ topic name via the ERRORS_DEAD_LETTER_QUEUE_TOPIC_NAME_CONFIG property? - bloku3: KIP-1034 allows users to send records to a specific topic even when a default DLQ topic is set. Do we plan to allow this in KIP-1328? Thanks, Uladzislau Blok On Mon, Apr 27, 2026 at 1:43 PM 권대호 <[email protected]> wrote: > > Hi all, > I'd like to start a discussion on KIP-1328: Dead Letter Queue Support for DSL Dropped Records. > > KIP: https://cwiki.apache.org/confluence/display/KAFKA/KIP-1328%3A+Dead+Letter+Queue+Support+for+DSL+Dropped+Records > JIRA: https://issues.apache.org/jira/browse/KAFKA-20439 > > Kafka Streams DSL operators currently drop certain records silently (e.g., null key/value, expired window records) with only a log warning and a metric increment. There is no way to capture these records > for analysis or reprocessing. > > This KIP proposes adding a writeToDlq() method to ProcessingContext, allowing DSL operators to route dropped records to the existing DLQ infrastructure introduced in KIP-1034. > > Looking forward to your feedback. > > Thanks, > Daeho Kwon
