Which action takes place when an incremental checkpoint occurs?

Question

Options

• AThe checkpoint position is advanced by the checkpoint process.
• BRedo entries are written by the checkpoint process to the online redo log files.
• CAll dirty buffers are written to data files by the checkpoint process.
• DThe checkpoint position is written to all the data file headers and the control file by the checkpoint
• EThe checkpoint position is written to the control file by the checkpoint process.

• A
  3% (1)
• C
  91% (32)
• D
  6% (2)

Explanation

Important caveat: the given answer C conflicts with Oracle's documented incremental checkpoint behavior. In Oracle, an incremental (or fast-start) checkpoint is a continuous background activity where CKPT advances the checkpoint position (low RBA) in the control file and signals DBWR to write dirty buffers from the oldest end of the dirty list - but it is DBWR, not the checkpoint (CKPT) process, that physically writes dirty buffers to data files, and only buffers up to the current checkpoint RBA are written, not all dirty buffers. Writing ALL dirty buffers and updating data file headers describes a full or normal checkpoint (e.g., triggered by a log switch), not an incremental one. Choice A ('checkpoint position is advanced by the checkpoint process') and Choice E ('checkpoint position is written to the control file') most accurately describe incremental checkpoint behavior per Oracle documentation. If this answer (C) appears on your exam, be aware it may represent an error in the question source; the technically correct description of an incremental checkpoint is that CKPT advances the checkpoint RBA in the control file while DBWR gradually writes dirty buffers - not that all dirty buffers are written by the checkpoint process.

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