[KAFKA-12845] Rollback change which requires join key to be non null on KStream->GlobalKTable

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 2.7.0
• Component/s: streams
• Assignee: Unassigned
• Reporter: Pedro Gontijo
• Created: 25/May/21 03:06
• Updated: 02/Jun/21 06:50
• Resolved: 02/Jun/21 06:50

Description

As part of KAFKA-10277 the behavior for KStream->GlobalKtable joins was changed to require non null join keys.

But it seems reasonable that not every record will have an existing relationship (and hence a key) with the join globalktable. Think about a User>Car for instance, or PageView>Product. An empty/zero key could be returned by the KeyMapper but that will make a totally unnecessary search into the store.

I do not think that makes sense for any GlobalKtable join (inner or left) but for left join it sounds even more strange.

 

Issue Links

• duplicates: KAFKA-12317 Relax non-null key requirement for left/outer KStream joins
• is caused by: KAFKA-10277 Relax non-null key requirement for KStream-GlobalKTable joins