Which background process prompts DBWn to begin writing dirty buffers. A. Process monitor B. Log writer C. System monitor D. Non of these processes E. Archiver

The process that prompts DBWn to begin writing dirty buffers in an Oracle database is typically the Log Writer (B).

As transactions occur in the database and data is modified, buffers become "dirty," meaning they contain changes that have not yet been written to disk. The Log Writer process is responsible for writing the redo log entries for these transactions to disk, and it works in conjunction with DBWn (Database Writer) to ensure that these changes are also flushed from memory to persistent storage.

Here's a breakdown of the other options:

1. Process Monitor (A) - Monitors the status of various background processes but does not directly trigger DBWn.
2. System Monitor (C) - Used for monitoring and managing system resources, not directly involved in writing dirty buffers.
3. None of these processes (D) - Incorrect because Log Writer is indeed involved.
4. Archiver (E) - Handles archiving of redo logs but does not trigger DBWn to write dirty buffers.

Thus, the correct answer is B. Log Writer.