If you regularly load large amounts of data into your staging tables, you will want to clear them out on a regular basis as part of your SQL Server maintenance plans. You can do this easily for individual batches using the MDS UI as follows:

Of course, this could be time consuming if you have many batches you need to clear. As with most MDS functions you can alternatively clear the staging tables by calling a SQL stored procedure—mdm.udpStagingClear. This can be run with a number of different parameters as described next:

mdm.udpStagingClear