Hi Team, I found a issue when using Partial mode Upsert. When getting a previous record before the merge, we always reuse the GenericRow object but not clean or modify _nullValueFields, see MutableSegmentImpl#getRecord. And PartialUpsertHandler will use the _nullValueFields which may expire to check column value is null. This will cause Partial Upsert to miss previous column data and not work.

thanks for reporting this. @User can you take a look?

thanks for reporting. Taking a look.

thanks for checking, we have fixed it on our own fork and strongly look forward to more partial upsert strategies, especially the custom script approach.😀

Cool. Can you contribute the fix back?