I wonder if this worth the price: an extra (thing_uniq) table and extra key column on partitioned tables. So pay an extra query to the thing_uniq table before i

I wonder if this worth the price: an extra (thing_uniq) table and extra key column on partitioned tables. So pay an extra query to the thing_uniq table before insert to target table. thing_uniq has one indexed column (the key). But we lose upsert.