Which statement is ture regarding checkpoints and recovery ?
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A checkpoint defines the highest system change number (SCN)
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All redo entries higher or at the SCN are known to be written to the data files.
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Only the redo records containing SCNs higher then the checkpoint need to be applied during recovery.
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The LOG_CHECKPOINT_INTERVAL initialization paramter specifies the amount of time beteen incremental checkpoints.
During recovery, Oracle only needs to apply redo records with SCNs higher than the checkpoint SCN because all changes up to and including the checkpoint SCN are already written to data files. This is the fundamental purpose of checkpoints - they reduce recovery time by establishing a point of consistency. Option A is incomplete - a checkpoint defines the highest SCN that's been written to disk. Option B is incorrect - redo entries at or below the checkpoint are already on disk. Option D confuses LOG_CHECKPOINT_INTERVAL with time-based intervals.