Failed to index using upsert method

Winnie_1234

Hi, during the initial stage, I had already loaded 6 months of data (hundreds of millions of records) with mapping using Magic ETL. I extracted the raw 6 months of data using Workbench, and Magic ETL connected to this raw dataset to perform the mapping.

Upon review, I noticed that I missed mapping one type of document — let's say type "AB". My Magic ETL includes many other document types as well.

Since only the rows with type "AB" are missing, I attempted to update just those rows using the upsert option. I selected the appropriate unique columns for the upsert in Magic ETL and confirmed that there were no empty columns among this upsert columns.

As shown in the screenshot, ALL steps loaded successfully — but it failed at the final stage, which is indexing.

Kindly advise.

Would concatenating the unique columns into a single new column as the upsert key work better, rather than selecting multiple columns as in the default setup?