The CONTROL_FILE_RECORD_KEEP_TIME parameter dictates how long reusable control file record slots are kept before they can be overwritten, with a default of 7 days. If all slots are in use and the retention period hasn't passed for the earliest entry, Oracle will automatically expand the control file section to create more slots, up to a maximum size. The message "kccrsz: expanded controlfile section" in the alert log simply indicates this expansion.
The control file itself is a vital binary file containing crucial metadata about the database, including:
- Database information (like
RESETLOGSSCN and timestamp, creation date, database name, ID). - History of archive logs.
- Records for tablespaces and datafiles (filenames, checkpoints, status).
- Redo thread information (current online redo logs).
- Current archive log mode.
- Log records (sequence numbers, SCN ranges).
- RMAN catalog details.
- Database block corruption information.
You can monitor the size, total number, and used record count of control file sections through the V$CONTROLFILE_RECORD_SECTION view.
