Fix ORA-38706/ORA-38707 Errors and Enable Oracle Flashback Database

Problem Overview

During testing the database returned the errors ORA-38706: Cannot turn on FLASHBACK DATABASE logging. and ORA-38707: Media recovery is not enabled.. The second message indicates the database is not running in ARCHIVE (media recovery) mode, which is required before Flashback can be enabled.

Prerequisite: Archive Mode

Before turning on Flashback, ensure the database operates in ARCHIVE mode. Verify this with the command: archive log list; The output should contain Database log mode Archive Mode.

Step‑by‑Step Solution

Shut down the database immediately: shutdown immediate Start the instance in mount mode: startup mount Enable ARCHIVE mode: alter database archivelog; Confirm the mode again: archive log list; Enable Flashback Database: alter database flashback on; Open the database:

alter database open;

Flashback Database Principle

Since Oracle 10g, Flashback Database provides rapid point‑in‑time recovery without restoring all data files. Oracle records the “pre‑image” of changed data blocks in Flashback logs. During recovery the database can roll back only the changed blocks, so the recovery time is proportional to the amount of change rather than the total size of the database.

Key requirements:

The database must be in ARCHIVE mode.

Flashback feature must be enabled (via alter database flashback on).

Verification

After completing the steps, re‑run alter database flashback on;. No error should be returned, confirming that Flashback Database is active.