OBIEE 11g: Manually Clearing Cache from Presentation Services

To manually clear ALL Cache from OBIEE Presentation services, go to:
Administration > Issue SQL >
   Call SAPurgeAllCache();

To manually clear Cache by specific Database, from the same path (Administration > Issue SQL)   

   Call SAPurgeCacheByDatabase('DB Name');
   ('DB Name' can be obtained from RPD's Physical Layer)