3.25 RedoLog

Use this Knowledge Script to monitor the following parameters:

Redo Log Contention: the number of times that a process tries to write an entry in the redo log buffer. The job raises an event and than stores data if the number of tries is different for subsequent iterations of the script.

The number of retries should be low. A high number of retries can adversely affect system performance, as processes must wait for buffers. If a process has to make numerous attempts to write an entry in the redo log buffer, you might need to allocate more space to the redo log buffer.

You can set a threshold value for the maximum number of times a process can try to write an entry in the redo log buffer. If the number of retries exceeds the threshold, an event is raised.
Redo Log Space Wait Ratio: the redo log space wait ratio. The redo log space wait ratio measures memory allocation. The ratio reflects the number of times the background process was requested to allocate space within the redo file per number of redo log entries. If this ratio increases, you might want to increase the size of the redo log buffer.

When the redo log space wait ratio exceeds the threshold you set, the job raises an event.
Redo Logs Not Archived: retrieve the number of redo logs that are not being archived, if archiving is turned on for a given Oracle database. The number of redo logs not archived is returned and compared against the thresholds you specify. The Knowledge Script retrieves the archive status for an Oracle database from the AppManager repository, which is updated during discovery. To enable archiving, you must rediscover the Oracle UNIX resources if the redo log archive is enabled after you discover resources.

When you enable data collection, the number of redo logs not archived is stored in the repository. You can set multiple thresholds for the number of redo logs not archived, with varying severities, and the job raises an event when any of these thresholds exceeds the value you specified.

The account you use to run this script must have SELECT permissions for the following tables:

V_$SGASTAT

V_$SYSSTAT

V_$VERSION

V_$LOG

3.25.1 Resource Objects

Oracle Database folders. When you drop a script on an Oracle Database folder, a job executes on that database and monitors only that database.

3.25.2 Default Schedule

The default interval for this script is Every 10 minutes.

3.25.3 Setting Parameter Values

Set the following parameters as needed:

Description	How to Set It
Oracle Username	Enter the username that this script needs to access the target databases. If you run this script on more than one database, configure each database with the same username. To use SYSDBA authentication, leave this parameter blank. The default is blank.
Redo Log
Redo Log Contention	Select Yes to monitor Redo Log Contention. The default is unselected.
Redo Log Space wait Ratio	Select Yes to monitor Redo Log Space Wait Ratio. The default is unselected.
Redo Log Not Archived	Select Yes to monitor Redo Log Not Archived. The default is unselected.
Event Notification
Raise event if threshold is exceeded for Redo Log Contention?	Select Yes to raise an event if the number of times that a process tries to rewrite an entry to the redo log buffer exceeds the threshold you set. The default is Yes.
Threshold - Maximum redo log buffer allocation retries	Enter a threshold for the maximum number of times that a process might try to rewrite an entry to the redo log buffer before the job raises an event. The default is 50.
Severity	Set the event severity level, from 1 to 40, to indicate the importance of the event. The default is 5 (red event indicator).
Raise event if threshold is exceeded for Redo Log Space Wait Ratio?	Select Yes to raise an event if the redo log space wait ratio exceeds the threshold you set. The default is Yes.
Threshold - Maximum redo log space wait ratio	Enter a maximum threshold for the redo log space wait ratio. The default is 0.0002.
Severity	Set the event severity level, from 1 to 40, to indicate the importance of the event. The default is 10 (red event indicator).
Raise event if threshold is exceeded for Redo Logs not Archived?	Select Yes to raise an event if the threshold exceeds the value you specified.The default is Yes.
Threshold - Maximum number of redo logs not archived	Specify a threshold for the maximum number of redo logs that have not been archived. The default is 6.
Severity	Set the event severity level, from 1 to 40, to indicate the importance of the event. The default is 5 (red event indicator).
Raise event if threshold is exceeded for Redo Logs not Archived?	Select Yes to raise an event if the threshold exceeds the value you specified. The default is unselected.
Threshold - Maximum number of redo logs not archived	Specify a threshold for the maximum number of redo logs that have not been archived. The default is 4.
Severity	Set the event severity level, from 1 to 40, to indicate the importance of the event. The default is 15 (yellow event indicator).
Raise event if threshold is exceeded for Redo Logs not archived?	Select Yes to raise an event if the threshold exceeds the value you specified. The default is unselected.
Threshold - Maximum number of redo logs not archived	Specify a threshold for the maximum number of redo logs that have not been archived. The default is 2.
Severity	Set the event severity level, from 1 to 40, to indicate the importance of the event. The default is 25 (blue event indicator).
Raise event if threshold is exceeded for Redo Logs not archived?	Select Yes to raise an event if the threshold exceeds the value you specified. The default is unselected.
Threshold - Maximum number of redo logs not archived	Specify a threshold for the maximum number of redo logs that have not been archived. The default is 1.
Severity	Set the event severity level, from 1 to 40, to indicate the importance of the event. The default is 35 (magenta event indicator).
Data Collection
Collect data for Redo Log Contention?	Select Yes to collect data for charts and reports. When you enable data collection, the Knowledge Script returns the number of times that processes attempted to write entries to the redo log buffer. The default is unselected.
Collect data for Redo Log Space Wait Ratio?	Select Yes to collect data for charts and reports. When you enable data collection, the Knowledge Script returns the redo log space wait ratio. The default is unselected.
Collect data for Redo Log not archived?	Select Yes to collect data for charts and reports. When you enable data collection, the Knowledge Script returns the number of redo logs not archived. The default is unselected.
Event severity for internal failure	Set the event severity level, from 1 to 40, to indicate the importance of the event. The default is 5 (red event indicator).