Use case: Moving data from production environment into empty test environment.

If source or target table is empty then there is no need to compare rows. In the frontend it looks like every row is processed in a loop, takes half a minute to process ~30000 records, and a lot more time to process a million records.

I suggest to perform a record count on the target table. If target table is empty, just suggest to copy over all rows in the source. If target table is not empty, then check source table. If source table is empty, then suggest to drop all rows in the target.

This could also be an option in the compare dialog ("Optimize for empty tables").