Hi chia, Thank you for the thoughtful feedback!
chia_10: I have added a clarification in the Proposed Changes section to address this. In this case, ListOffsetsRequest will resolve to the Log End Offset, but this is not a fallback to `latest`. The distinction matters: `latest` is a direct seek to the Log End Offset, whereas `by_start_time` always anchors to the group creation timestamp and lets the lookup result follow naturally. The consumer will begin consuming any new records produced after this point normally. chia_11: I have introduced a new exception `GroupCreationTimeUnknownException` to signal this specific condition. chia_12: I have updated the KIP to expose the group creation timestamp via `AdminClient.describeConsumerGroups()` , accessible through `ConsumerGroupDescription.groupCreationTimeMs()`. This is backed by a new `GroupCreationTimeMs` field in `ConsumerGroupDescribeResponse. Best Regards, Jiunn-Yang > Chia-Ping Tsai <[email protected]> 於 2026年4月1日 下午2:33 寫道： > > hi Jiunn > > thanks for updating KIP. I have a couple of questions. > > chia_10: What happen if the group creation time is strictly greater than the > timestamp of the latest record in the partition? Will the consumer fall back > to the "latest" offset behaviour in this case? It could be good to elucidate > that in the KIP > > chia_11: Could you specify which exact exception will be thrown when the > group creation time is unknown > > chia_12: Since the group creation time is now a critical semantic anchor, > should we also expose it via the `DescribeGroupsResponse`? > > Best, > Chia-Ping > > On 2026/03/05 11:14:31 黃竣陽 wrote: >> Hello everyone, >> >> I would like to start a discussion on KIP-1282: Prevent data loss during >> partition expansion for dynamically added partitions >> <https://cwiki.apache.org/confluence/x/mIY8G> >> >> This proposal aims to introduce a new auto.offset.reset policy >> by_start_time, anchoring the >> offset reset to the consumer's startup timestamp rather than partition >> discovery time, to prevent >> silent data loss during partition expansion. >> >> Best regards, >> Jiunn-Yang
