You are using the following command to clear the log file group: ALTER DATABASE CLEAR LOGFILE GROUP 2; In which case would the command be successful?

An active redo log group is currently being written to by the log writer process, and Oracle will not permit it to be cleared while it is actively receiving redo entries.

The current group is the most recently selected group for writing and cannot be cleared because it may contain redo that has not yet been archived or checkpointed.

The database open mode (MOUNT vs OPEN) alone does not determine whether CLEAR LOGFILE succeeds; the deciding factor is the archived status of the target group, not the instance state.

CLEAR LOGFILE succeeds when the target group has already been archived because the archived copy preserves the redo data, making it safe to reinitialize the online log. Oracle enforces this requirement strictly to prevent data loss - if the group has not yet been archived, you must use CLEAR UNARCHIVED LOGFILE instead, which explicitly acknowledges the potential loss of redo.