-
Title
'The percentage of time spent by sessions waiting on redo operations' alarms -
Description
Alarms similar to the following are fired
'The percentage of time spent by sessions waiting on redo operations 17.45%'
-
Cause
The alarms were justified, but the sensitivity was set high.
-
Resolution
To change the thresholds via the foglight dashboards and change the registries values.
Administration | Rules and Notifications | Manage Registry Variables | Search for DBO_Redo_Wait_Contention then change values.
Below is the table with the default values:
| Severity | Registry Name | Default Value |
--------------------------------------------------------------------------------------------------------------------------
| Warning | DBO_Redo_Wait_Contention_Low | 5 |
| Critical | DBO_Redo_Wait_Contention_Medium | 20 |
--------------------------------------------------------------------------------------------------------------------------The higher the numbers will be, the less sensitivity will be.
For example: the user can change the default value for Warning to 30 and Critical to 50 (this is the average we conclude from the screen shots about the Redo activity the customer executes).