Hi team, in the doc of Stream Ingestion with Upsert, i saw this

Do note that you can't increase the partitions in future for upsert enabled tables so you need to start with good enough partitions (atleast 2-3X the number of pinot servers)

May I know why that we can’t increase the partitions in future for upsert enabled tables?

Hi it is because the upsert metadata is kept at the partiton level so if you increase the partitions and your record with primary key A goes to the new partition, it will simply upsert the wrong or no record at all

Thanks

if a segment gets deleted due to retention its metadata is removed as well