Multiple choice

One of the tasks of a DBA is to periodically monitor the alert log file and the background trace files. In doing so, the DBA notices repeated messages indicating that Log Writer (LGWR) frequently has to wait for a redo log group because a checkpoint has not completed or a redo log group has not been archived. What should he do to eliminate the wait LGWR frequently encounters?

  1. Increase the number of redo log groups to guarantee that the groups are always available to LGWR

  2. Increase the size of the log buffer to guarantee that LGWR always has information to write

  3. Decrease the size of the redo buffer cache to guarantee that LGWR always has information to write

  4. Decrease the number of redo log groups to guarantee that checkpoints are completed prior to LGWR writing
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

LGWR waits when redo log groups are not available due to incomplete checkpoints or archiving. Adding more redo log groups ensures that at least one group is always available for LGWR to write to, preventing these waits. Option B (increasing log buffer) doesn't address log group availability. Option C (decreasing buffer) would worsen performance. Option D (decreasing groups) would make the problem worse by reducing availability.

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