> Just doing a hash join is simply the better option. Maybe he meant just that - hash join has to populate hashtable before joining. Regarding B-Tree index, p

> Just doing a hash join is simply the better option. Maybe he meant just that - hash join has to populate hashtable before joining. Regarding B-Tree index, perhaps he thought Automatic Index management - https://docs.microsoft.com/en-us/sql/relational-databases/automatic-tuning/automatic-tuning?view=sql-server-ver15#automatic-index-management https://docs.microsoft.com/en-us/sql/relational-databases/au... - but it must be enabled explicitly. But I don't feel like it is "on-the-fly". Rather in-background.