You specify the location of the log messages and the size and number of log files, and configure the properties of the log server in the configuration tool. By default, log messages are saved to the cogserver.log file located in c8_location/logs. They can also be saved in a database. For more information, see the Installation and Configuration Guide.
For more information about the log service, see Dispatchers and Services.
You set logging levels to specify the events and messages to record in the log file or in the log database. An event is an occurrence in your Cognos 8 environment that is significant enough to be tracked, such as starting or stopping a service.
You can set a different logging level for each dispatcher service. You can do this for each dispatcher or for all dispatchers in the same folder. By setting different logging levels for different services you can reduce the amount of irrelevant logging information. For example, if you must troubleshoot the batch report service, you can select a detailed logging level for just that service, keeping log messages to a minimum. The logging level for a service applies to all its components.
Note: The log service does not have logging levels associated with it.
The following table indicates the details that each logging level logs.
Details | Minimal | Basic | Request | Trace | Full |
System and service startup and shutdown, runtime errors | | | | | |
User account management and runtime usage of Cognos 8 | | | | | |
Use requests | | | | | |
Service requests and responses | | | |||
All requests to all components with their parameter values | | | |||
Third-party queries to Cognos 8 components (native query) | | |
You can maintain system performance by managing the amount of logging performed by the server. Since extensive logging affects server performance, increasing the logging level may negatively affect the performance of Cognos 8.
The default logging level is Minimal. Use Full logging level only for detailed troubleshooting purposes because it may significantly degrade server performance.
You can collect information about report validation levels by setting the corresponding logging level. Report validation messages can be included in system log messages.
You can use the validation information in different ways. If the system is delivering a generally poor response, you can set logging to a higher level. The additional information can help you determine which reports are at fault and why. If you see warning messages in the logs, this may mean that users are receiving questionable results. You can alert the owners of the offending reports.
There are four report validation levels and five logging levels. The following table shows the correspondence between them.
| Report validation level | Logging level |
| Error | Minimal, Basic |
| Warning | Request |
| Key Transformation | Trace |
| Information | Full |
The higher you set the logging level, the more it degrades system performance. Normally, you set the level to Minimal or Basic to collect errors, or to Request to collect errors and warnings.
For information about reports and report validation, see the Report Studio Professional Authoring User Guide.
If you want to create audit reports 
that include the queries that are run against
your reporting data source, you must enable native query logging.
You can use native query logging to learn what kinds of information
users want or whether a report is running efficiently.
Native query logging is part of Request level logging. However, if you are using audit reports, you can enable native query logging independently from Request level logging, as described in the following steps.
For information on setting logging levels for audit reports, see Audit Reports.
You set logging levels to specify the events and messages to record in the log file or in the log database. An event is an occurrence in your Cognos 8 environment that is significant enough to be tracked, such as starting or stopping a service. For more information, see Logging Levels.
Logging levels that you set for the system apply to all dispatchers and services. Logging levels that you set at the dispatcher level apply to all services that are associated with the dispatcher. Logging levels that you set for individual services apply to the service across all dispatchers.
Logging levels that are set for dispatchers override logging levels that are set for the system level. Logging levels that are set for services override logging levels that are set for dispatchers or the system.
You must have the required permissions to access Cognos Administration functionality. See Secured Functions and Features.
Start Cognos Connection.
In the upper-right corner, click Launch, Cognos Administration.
On the Status tab, click System.
In the upper left corner of the Scorecard pane, click the arrow to view the Change view menu, and then click All servers, All server groups, All dispatchers, or Services, depending on where you want to set logging levels.
Click the arrow next to the item to view the Actions menu, and then click Set properties. For example, to set logging levels for the system, click the arrow next to the Actions menu.
Click the Settings tab.
From the Category menu, click Logging.
From the Value menu, select the logging level you want for the service.
If native query logging is available for the service and you want
to use it, select the audit the native query check box.
Click OK.
