Interleaving online operations and data loading is not a problem. One can count 10K triples load rate per core if operating in memory. For example loading on one core and doing online queries on 7 cores should present no problem.
The system keeps a running count of different database operations performed on each connection, e.g. random index access, sequential index access, disk read etc. These can be programmatically accessed using the db_activity () SQL function.