Waiting for log switch because current log is full and LGWR needs to complete writing to current log and open the new log or some other request to switch log files.
The rest of the information in this section is only valid for this metric when it appears in either the Enterprise Manager Grid Control or the Enterprise Manager Database Control (if applicable).
The following table shows how often the metric's value is collected and compared against the default thresholds. The 'Consecutive Number of Occurrences Preceding Notification' column indicates the consecutive number of times the comparison against thresholds should hold TRUE before an alert is generated.
|
Target Version |
Evaluation and Collection Frequency |
Upload Frequency |
Operator |
Default Warning Threshold |
Default Critical Threshold |
Consecutive Number of Occurrences Preceding Notification |
Alert Text |
|
pre-10g |
Every Minute |
After Every Sample |
> |
20 |
Not Defined |
3 |
%value%%% of service time is spent waiting on the 'log file switch completion' event. |
(DeltaLogFileSwitchCompleteTime/DeltaServiceTime)*100 where:
DeltaLogFileSwitchCompleteTime: difference of 'sum of time waited for sessions of foreground processes on the 'log file switch completion' event' between sample end and start
DeltaServiceTime: difference of 'sum of time waited for sessions of foreground processes on events not in IdleEvents + sum of 'CPU used when call started' for sessions of foreground processes' between sample end and start
See Idle Events
For the log file switch (checkpoint incomplete) event:
Check if there are too few, or too small redo logs. If there are a few redo logs or small redo logs, and the system produces enough redo to cycle through all the logs before DBWR has been able to complete the checkpoint, then increase the size or number of redo logs. This is often the easiest solution but may increase time to recovery.
Check if DBWR is slow, possibly due to an overloaded or slow I/O system. Check the DBWR write times, check the I/O system, and distribute I/O if necessary.
Related Topics
About Alerts
About the Metric Detail Page
Editing Thresholds
Understanding Line Charts
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