it could be due to different hardware, different workload, or different plan for one or more SQL statements (which in its turn can be due to a large number of factors). You should start by profiling the upload process and determining whether it's a single SQL statement that is taking longer on one of the databases, or the entire database is performing slowly. Depending on your database version and your license, there are various tools for this, e.g. AWR, ASH, extended SQL trace, dbms_profiler, dbms_hprof etc.
I have some uploads happening in two different db's. All the db objects and tables are associated are same. But in one DB it running slower. What could be the reasons?
Two red cars. With the same number of steering wheels, tires, and axles. One if faster that the other. What could the reasons be?