Master Data Compression

Is there a function in BW 3.0 to compress time-dependent attributes? Say 0costcenter has a time-dependent attribute 0PROFIT_CTR and the load for 0costcenter attribute is schedule daily. However, changes to 0PROFIT_CTR is not that frequent. Since it is a daily load, there will be large number of records for 0costcenter master data over the time even the attribute value remains the same. I remember seeing documentation from SAP saying 3.0 has a master data compression function to collapse multiple master data if their values are the same. I'm working on BW 3.1 system and have not found this function yet. Can anyone help?

Thanks a lot!

Bill