Hi Ganesh ,
You can define the restrictions in the ECC level in the tables ROOSPRMS and ROOIDOCPRMS. but that would be applicable for all the data sources which is not what you need .
You need to take care of the data selection parameter from the Info Package as suggested by Martin but also include the parameter for number of parallel processes as well .
You should also need to consult Basis team to increase the memory parameters as well.
Thanks
Kamal