An Autoindex job that utilizes a data file performs very slowly, perhaps only several documents per minute.
Setting iterated records to the file cabinet means that the workflow will select a match code from the file cabinet and search the entire data file for it, and this process is repeated for each record in the file cabinet. If the data file contains thousands of records, this will be very slow because it is not efficient like a database search would be.
Modify the workflow and set iterated records to be on the data file. This will cause searches to be run on the file cabinet, which is a database, and perform much better.