Sets the maximum file size, in bytes, for a file to be mapped into the process address space. If no value is specified, it defaults to 10MB.
                 The syntax of this parameter in the DB_CONFIG file is a
                 single line with the string
                 set_mp_mmapsize, one or more whitespace
                 characters, and the size in bytes.
            
For more information, see DB_ENV->set_mp_mmapsize().