What is the purpose of a checkpoint?
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Write the current redo log to the archived redo log.
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Synchronize the modified data blocks in memory with the datafiles on disk.
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Ensure database consistency.
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Ensure that data blocks are read into memory as quickly as possible.
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Keep track of redo entries.
A checkpoint synchronizes modified data blocks in the buffer cache with the datafiles on disk, ensuring database consistency and reducing recovery time. During a checkpoint, the database writer (DBWn) processes write dirty blocks to datafiles, and the checkpoint position in redo logs is updated. Options A, C, and D are incorrect because checkpoints don't archive redo logs, don't directly ensure consistency (that's a result of the sync), and don't control data block reading speed.