Master data lock when updating through a function module

Hi All,

I have a master data update screen which calls a function module( On click of "Save" ) to update master data in BW. In the function module, i am using following standard function modules to update and activate the data:

1. RSNDI_MD_ATTRIBUTES_UPDATE

2. RSDDS_ATTRIBUTES_ACTIVATE

The problem in this case is as follows:

When more than one person, clicks the "Save" button at the same time, then one of the person is not able to update the data in BW eventhough he/she is trying to update a different record or trying to insert a new record. How can i solve the problem ? I would like to know whether any of the function module listed above locks the entire master data table of the infoobject ?

Points will be awarded.

Thanks,

Satya