A control file, as the name suggests, is just a file and is made at the time of the database creation with a finite size. The size of a control file is mainly based on the following parameters:
The initial size of the control file is determined based on the values of these parameters. To accommodate subsequent changes to these parameters after the database creation, the control file will be expanded dynamically. Unlike the default block size (determined by the
DB_BLOCK_SIZE parameter), the block size of a control file will be fixed and hardcoded for a specific database release; for database release 12c, it is fixed for 16 KB. You can check ...