Multiple choice technology databases

Which background process reads the redo log buffer and writes it to a file ?

  1. ARCn

  2. DBWn

  3. CKPT

  4. LGWR

  5. PMON

  6. SMON
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D Correct answer
Explanation

The Log Writer (LGWR) background process reads redo entries from the redo log buffer in memory and writes them to online redo log files on disk. This is critical for durability - committed transactions must be written to redo logs before acknowledgment. ARCn archives redo logs, DBWn writes dirty buffers, CKPT updates file headers, and PMON/SMON handle process and transaction recovery.

AI explanation

LGWR (Log Writer) is the Oracle background process responsible for flushing the contents of the redo log buffer in memory to the online redo log files on disk. DBWn writes modified data blocks (not redo) from the buffer cache to datafiles, CKPT updates checkpoint information, and ARCn archives filled redo logs — none of these write the redo buffer itself.

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