Hello everyone,
I have been already write revealing information that control file stores: https://mustafakalayci.me/2020/08/11/control-file-content-and-the-limits/.
Data in control file is separated into “SECTIONS” and you can see those sections name (type) via V$CONTROLFILE_RECORD_SECTION view. for example, database separates a section for “BACKUP SET”s. every section has a record size limit . All those information can be queried via v$controlfile_record_section of course.
RECORDS_TOTAL number of records allocated for that section.
RECORDS_USED number of used records.
You might encounter an alert log message from time to time like “Expanded controlfile section 11 from 100 to 200”. this is a message that database need to store more data in control file and currently allocated space is not enough, so oracle expands the control file. in this sample message, 100 is current RECORDS_USED and RECORDS_TOTAL. since all records are filled, it expands to 200, so RECORDS_TOTAL become 200. how about the section? what is section 11? unfortunately there is no SECTION_ID but V$controlfile_record_section always return rows in specific order and you can use this select to learn section ids:
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 |
Select rownum-1 section_code, type, records_total, records_used from v$controlfile_record_section; SECTION_CODE TYPE RECORDS_TOTAL RECORDS_USED ------------ -------------------------------- ------------- ------------ 0 DATABASE 1 1 1 CKPT PROGRESS 11 0 2 REDO THREAD 8 1 3 REDO LOG 16 8 4 DATAFILE 1024 12 5 FILENAME 4146 31 6 TABLESPACE 1024 14 7 TEMPORARY FILENAME 1024 3 8 RMAN CONFIGURATION 50 0 9 LOG HISTORY 584 561 10 OFFLINE RANGE 1063 22 11 ARCHIVED LOG 896 561 12 BACKUP SET 1022 2 13 BACKUP PIECE 1006 2 14 BACKUP DATAFILE 1063 2 15 BACKUP REDOLOG 215 0 16 DATAFILE COPY 1000 3 17 BACKUP CORRUPTION 1115 0 18 COPY CORRUPTION 1227 0 19 DELETED OBJECT 818 590 20 PROXY COPY 1004 0 21 BACKUP SPFILE 131 2 22 DATABASE INCARNATION 292 2 23 FLASHBACK LOG 2048 0 24 RECOVERY DESTINATION 1 1 25 INSTANCE SPACE RESERVATION 1055 1 26 REMOVABLE RECOVERY FILES 1000 1 27 RMAN STATUS 141 43 28 THREAD INSTANCE NAME MAPPING 8 8 29 MTTR 8 1 30 DATAFILE HISTORY 57 0 31 STANDBY DATABASE MATRIX 128 128 32 GUARANTEED RESTORE POINT 2048 0 33 RESTORE POINT 2108 0 34 DATABASE BLOCK CORRUPTION 8384 0 35 ACM OPERATION 64 11 36 FOREIGN ARCHIVED LOG 1002 0 37 PDB RECORD 10 3 38 AUXILIARY DATAFILE COPY 128 0 39 MULTI INSTANCE REDO APPLY 1 0 40 PDBINC RECORD 113 0 41 TABLESPACE KEY HISTORY 151 0 |
So, 11 is ARCHIVED LOG. which means to be able to store currently required (based on your deletion policy in rman) database need to increase number of records in control file.
Database needs to increase those sections when required data to be stored increase. You can see the alert log messages above when this occur.
wish you all good, healthy days.