Which two are true about flashback features in Oracle Database 19c and later releases? (Choose two.)
A.
Flashback logs are automatically purged when DB_FLASHBACK_RETENTION_TARGET is set lower than the time they have already been retained.
B.
Flashback logs are monitored and proactively deleted when beyond the retention period defined in DB_FLASHBACK_RETENTION_TARGET only after there is space pressure.
C.
Flashback logs are monitored and proactively deleted when beyond the retention period defined in DB_FLASHBACK_RETENTION_TARGET before there is space pressure.
D.
Flashback logs are monitored for being older than the retention period defined in DB_FLASHBACK_RETENTION_TARGET and can be deleted by an administrator written event trigger.
E.
Flashback logs are automatically purged whenever the value of DB_FLASHBACK_RETENTION_TARGET is changed.
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.
In scenarios where a sudden workload spike causes a large number of flashback logs to be created, the workload is monitored for a few days before deleting flashback logs that are beyond the retention period. This avoids the overhead of recreating the flashback logs, if another peak workload occurs soon after.
Correct answer: A,C
A and D are true.
Oracle until the end will try to don't delete flashback logs. "Proactively" makes sentences false.
D is absolutely possible, you can selected on data dictionary tables and set up an event trigger (ex. Database logon, DB scheduler, etc.) to purge logs, but it is not recommended.
A and B for me.
The oldest flashback logs may be deleted if there is space pressure in the FRA where the flashback logs are stored.
https://docs.oracle.com/en/database/oracle/oracle-database/23/haovw/oracle-flashback-best-practices.html#GUID-3E255563-B001-4AC1-A2E0-1884BF58D6C0
correct ans: AC
Until Oracle Database 19c, flashback logs that are beyond the flashback retention period set through the
db_flashback_retention_target initialization parameter are marked as reclaimable but are not
purged until there is space pressure. The reclaimable flashback logs are deleted only when the fast
recovery area is running out of space. The DBA cannot manually delete the flashback logs. This means that
when a backup needs to be completed and the FRA is 100 % full, the backup operation must wait until the
reclaimable flashback logs are purged to free space in the FRA.
With Oracle Database 19c, flashback logs beyond the retention period are proactively deleted without
degrading the flashback performance and before there is space pressure. The flashback log space is
tracked and monitored proactively to provide flashback log retention in a transparent manner.
I think its A and C. starting from 19c.
Starting with Oracle Database Release 19c, Oracle Database monitors flashback logs in the fast recovery area and automatically deletes flashback logs that are beyond the retention period (Not Waiting for FRA Crunch). When the retention target is reduced, flashback logs that are beyond the retention period are deleted immediately.
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