Q42. Which two are true about reclaiming space used by Flashback logs in Oracle Database 19c and later releases?
- A. Space might be reclaimed proactively before space pressure occurs.
- B. Space is only reclaimed when there is space pressure in the Fast Recovery Area (FRA).
- C. Space is always reclaimed automatically when the retention period for Flashback logs is lowered.
- D. Space might be reclaimed automatically when the retention period for Flashback logs is lowered.
- E. Space is always reclaimed proactively before space pressure occurs.
Answer: AD
Starting with Oracle Database Release 19c, the management of space in the fast recovery area is simplified. Oracle Database monitors flashback logs in the fast recovery area and automatically deletes flashback logs that are beyond the retention period. When the retention target is reduced, flashback logs that are beyond the retention period are deleted immediately.
https://docs.oracle.com/en/database/oracle/oracle-database/19/bradv/maintaining-rman-backups.html#GUID-26C1A1E8-5555-4399-9DD1-39BA90E45A0C
B. Space is only reclaimed when there is space pressure in the Fast Recovery Area (FRA). This is not entirely accurate. While space pressure in the FRA can trigger reclamation, proactive reclamation might occur even before space pressure arises.
C. Space is always reclaimed automatically when the retention period for Flashback logs is lowered. This is not guaranteed. Automatic reclamation might happen, but it’s not always immediate or guaranteed.
E. Space is always reclaimed proactively before space pressure occurs. This is also not entirely true. Proactive reclamation might happen, but it’s not always guaranteed to occur before space pressure arises.
Key Points:
Proactive Reclamation: Oracle Database 19c and later versions may proactively reclaim Flashback log space before space pressure occurs, aiming to prevent issues and maintain FRA capacity.
Retention Period: Lowering the retention period for Flashback logs can potentially trigger automatic reclamation, but it’s not always immediate or guaranteed.
Space Pressure: Space pressure in the FRA can also initiate reclamation, but it’s not the sole factor.
Manual Control: You can manually reclaim Flashback log space using commands like ALTER DATABASE FLASHBACK OFF and ALTER DATABASE FLASHBACK ON.
Monitoring and Management: It’s essential to monitor Flashback log usage and FRA space to ensure adequate space availability and proactively address potential issues.