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.
control_file_record_keep_time parameter can also be set to zero to prevent keep time related controlfile expansion.
ReplyDeleteThis parameter applies only to records in the control file that are circularly reusable (such as archive log records and various backup records). It does not apply to records such as datafile, tablespace, and redo thread records, which are never reused unless the corresponding object is dropped from the tablespace.