Sunday, 26 July 2009

Performance Tuning - Question 017

One way to determine the frequency of checkpoints is to set which of the following parameters and then check the alert.log file for messages?

A. LOG_CHECKPOINTS_TO_ALERT

B . LOG_SIMULTANEOUS_COPIES

C . LOG_CHECKPOINT_TIMEOUT

D . ALERT_LOG_CHECKPOINTING

Explanation:

Answer A: Setting LOG_CHECKPOINTS_TO_ALERT causes the checkpoint process to write a message to the alert log for the instance. You can then compare the timestamp of each message to determine checkpoint frequency. ALERT_LOG_CHECKPOINTING is not a valid parameter. LOG_SIMULTANEOUS_COPIES was used to configure redo copy latches prior to Oracle8i and is no longer supported.. LOG_CHECKPOINT_TIMEOUT specifies the maximum amount of time in seconds a dirty buffer can remain in the database buffer cache before DBWn must write it to disk.

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