Applies to:
Oracle Database Cloud Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database - Enterprise Edition - Version 11.2.0.2.0 and later
Oracle Database Cloud Schema Service - Version N/A and later
Information in this document applies to any platform.
For the purposes of this document, the following fictitious environment is used as an example to describe the procedure:
Primary Database: MYDB
Disk Group: +FRA
Symptoms
NOTE: In the images and/or the document content below, the user information and environment data used represents fictitious data from the Oracle sample schema(s), Public Documentation delivered with an Oracle database product or other training material. Any similarity to actual environments, actual persons, living or dead, is purely coincidental and not intended in any manner.
For the purposes of this document, the following fictitious environment is used as an example to describe the procedure:
Primary Database: MYDB
Disk Group: +FRA
Seeing messages like this in the alert log showing files being deleted from the flash recovery area (FRA) and wondering what is happening?
2011-09-30 10:03:43.574000 -05:00
Deleted Oracle managed file +FRA/mydb/archivelog/2011_09_30/thread_1_seq_11747.266.763204175
Deleted Oracle managed file +FRA/mydb/archivelog/2011_09_30/thread_1_seq_11751.462.763204177
2011-09-30 10:03:45.876000 -05:00
Deleted Oracle managed file +FRA/mydb/archivelog/2011_09_30/thread_1_seq_11739.782.763204163
2011-09-30 10:03:47.034000 -05:00
Deleted Oracle managed file +FRA/mydb/archivelog/2011_09_30/thread_1_seq_11734.748.763204167
2011-09-30 10:05:09.361000 -05:00
Deleted Oracle managed file +FRA/mydb/archivelog/2011_09_30/thread_1_seq_11735.469.763204169
2011-09-30 10:05:51.057000 -05:00
Deleted Oracle managed file +FRA/mydb/archivelog/2011_09_30/thread_1_seq_11755.592.763204153
Deleted Oracle managed file +FRA/mydb/archivelog/2011_09_30/thread_1_seq_11753.627.763204159
They cannot understand why this was done. Space pressure?
There was 20% free in the FRA before, during, and after we restored the logs.
Why was Oracle automatically deleting these archivelogs that we needed?
The db_recovery_file_dest_size is correct and matches the disk group size perfectly.
Changes
They had restored some archivelogs that had been deleted, as a the Goldengate product needed them.
After restoring the archivelogs they needed, they noticed that the +FRA diskgroup was still at 20% free.
All of the requested logs were now on disk again. Later, though, when trying to access some of the
very same restored archivelogs, they found they had been mysteriously deleted.
Cause
With Oracle 11.2 and onwards, Oracle will start to purge the files in the FRA when the SPACE_USED reaches 80% of SPACE_LIMIT as specified by the db_recovery_file_dest_size parameter.
Solution
With Oracle 11.2 and onwards, Oracle will start to purge the files in the FRA when the SPACE_USED reaches 80% of SPACE_LIMIT.
Two queries you can run to look at space usage in the FRA are:
select * from V$FLASH_RECOVERY_AREA_USAGE;
SELECT substr(name, 1, 30) name
, space_limit/(1073741824) AS Quota_GB
, space_used/(1073741824) AS Used_GB
, space_reclaimable/(1073741824) AS Reclaimable_GB
, number_of_files AS files
FROM V$RECOVERY_FILE_DEST ;
