[rawgabbit]

I have run into this scenario a few times where the multi-hour processes produces an explosion of rows that no one cared to troubleshoot further. They only wanted to de-duplicate the final result.

In practice, I ended up creating a skeleton table that not only had the appropriate constraints for de-duplication. But I would also create mostly empty rows (empty except for the required column key ID fields) with the exact rows they were expecting. And then I would perform an UPDATE <skeleton> ... FROM <complicated join>. It is a hack but if there was no desire to rewrite a process that was written years ago by teams of consultants, I can only do what I can do.