[KAFKA-13499] Avoid restoring outdated records

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: streams
• Assignee: Danica Fine
• Reporter: Matthias J. Sax
• Created: 02/Dec/21 22:01
• Updated: 24/May/23 06:36

Description

Kafka Streams has the config `windowstore.changelog.additional.retention.ms` to allow for an increase retention time.

While an increase retention time can be useful, it can also lead to unnecessary restore cost, especially for stream-stream joins. Assume a stream-stream join with 1h window size and a grace period of 1h. For this case, we only need 2h of data to restore. If we lag, the `windowstore.changelog.additional.retention.ms` helps to prevent the broker from truncating data too early. However, if we don't lag and we need to restore, we restore everything from the changelog.

Instead of doing a seek-to-beginning, we could use the timestamp index to seek the first offset older than the 2h "window" of data that we need to restore, to avoid unnecessary work.

Issue Links

• relates to: KAFKA-7934 Optimize restore for windowed and session stores