The broker computes the highest applied system change number (SCN) and uses its value to find the last continuous log file that was successfully archived to the standby database. Redo data in all subsequent log files, including the current online redo log file, are counted as log files for potential data loss and will be unrecoverable if the primary database goes down at this point.
For example, if log files 1, 2, 3, 6, 7, and 9 are received on the standby database, and if log 10 is the current online log file, and if log apply services are currently applying log 1, the last continuous log after the highest applied SCN is log 3. All log files after log 3, that is log files 4 through 10, are counted as data not received. If the primary database goes down at this point, all redo data in log files 4 through 10 are lost on the standby database.
If the primary database is multithreaded (in a RAC database), the broker computes the highest applied SCN for every thread and totals the numbers. If the primary database has multiple incarnations (for example, due to a flashback operation) and the standby database is in a different incarnation from the primary database, the computation is done on each incarnation and the results are then totaled.
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 |
|
10.1.0.x |
Every 5 Minutes |
After Every Sample |
> |
1 |
3 |
1 |
Standby database %dg_name% has not received the last %value% logs from the primary database. |
For this metric you can set different warning and critical threshold values for each "Name" object.
If warning or critical threshold values are currently set for any "Name" object, those thresholds can be viewed on the Metric Detail page for this metric.
To specify or change warning or critical threshold values for each "Name" object, use the Edit Thresholds page. See Editing Thresholds for information on accessing the Edit Thresholds page.
Not available
No user action is required.
Related Topics
About Alerts
About the Metric Detail Page
Editing Thresholds
Understanding Line Charts
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