Spotlight on Oracle 11.0 - Getting Started Guide

Log Switch Time Alarm

The Log Switch Time alarm occurs if the amount of time spent waiting for log switch events exceeds a threshold.

A log switch must occur whenever a log file is full. Usually the log switch time is trivial, but it can become significant in the following circumstances:

• The next redo log to be used is not available because the checkpoint that started when the log was switched is not complete, or
• The redo log has not yet been archived.

These problems usually occur when redo log I/O rates are sub-optimal, or when the number or size of redo logs is insufficient. For more information, see Improve Redo Log Writer Performance.