#include <db.h> int DB->set_heap_regionsize(DB *db, u_int32_t npages);
Sets the number of pages in a region of a database configured to use the Heap access method. If this method is never called, the default region size for the database's page size will be used. You can set the database page size using the DB->set_pagesize() method.
         The DB->set_heap_regionsize() method may not be
         called after the DB->open()
         method is called. If the database already exists when 
         DB->open()  is called, the
         information specified to
         DB->set_heap_regionsize() will be
         ignored. If the specified region size is larger than the maximum
         region size for the database's page size, an error will be
         returned when DB->open()  is
         called.  The maximum allowable region size will be included in the
         error message.
     
         The DB->set_heap_regionsize() 
            
                  method returns a non-zero error value on failure and 0 on success.
            
            
        
     
             The DB->set_heap_regionsize() 
            
                 method may fail and return one of the following non-zero errors:
            
            
        
        
If the specified region size was too small; the method was called after DB->open() was called; or if an invalid flag value or parameter was specified.