Q45. Which three are true about the FLASHBACK DATABASE feature?
- A. FLASHBACK LOGS are archived after the log switch.
- B. It requires that the target database be in ARCHIVELOG mode.
- C. FLASHBACK DATABASE only uses FLASHBACK LOGS to get the database to the desired flashback time.
- D. It always generates REDO and UNDO.
- E. A database can be flashed back using SQL*PLUS.
- F. Queries and DML have the same FLASHBACK LOG overhead when flashback is enabled for a database.
Answer: BEF
Key points about FLASHBACK DATABASE:
Requires ARCHIVELOG mode: The database must be in ARCHIVELOG mode to enable FLASHBACK DATABASE, as it relies on archived redo logs for flashback operations.
SQL*PLUS usage: You can initiate a FLASHBACK DATABASE operation using the FLASHBACK DATABASE command in SQL*PLUS.
Overhead considerations: Enabling FLASHBACK DATABASE introduces some overhead due to the generation of flashback logs. However, this overhead applies to both queries and DML operations equally.
Archival distinction: FLASHBACK LOGS are not archived like traditional redo logs. They are managed separately within the Fast Recovery Area (FRA).
Combined log usage: FLASHBACK DATABASE may use both FLASHBACK LOGS and archived redo logs to achieve the desired flashback point, depending on the specific flashback time and available data.