I hope you have several direct input sessions and run it in parallel.
Performance has many influencing factors, like hardware, workload in peak times (day vs night, holidays vs workdays) and others . In extraordinary situations we have our basis team add temporary more SAPS (which means that development and test system becomes slower).
I am currently migrating a system with 2.5 million plant records and one of my analyzing reports ran for 17 days to evaluate which material was not used in the last 2 years, has no stock, no Boms, no contracts, no sales order...