Activating Data Transfers for BW Statistics 
Use
For each InfoCube, for each area in OLAP and for each area in warehouse management, you can activate and de-activate data that has been saved and transferred individually. This reduces the time it takes to transfer and save data in the BW statistics, even in large installations.
Procedure
Remove any indicators that are already set for InfoCubes, for which you do not want to run BW statistics.

By deleting old BW statistics data, you save space in the data base and speed up the data extraction process.