7.12. Editing Database Cluster Log Settings

To display the Edit Log Settings dialog, select Edit => Log Settings. This dialog enables you to determine if the backend should produce a log, what should be in the log, and where the log should be stored.

The General tab controls whether the log is on or off and, if it is on, is used to determine if the data is sent to the /var/log/rhdb/dbclustername file or to the system syslog(8) facility. In the latter case, you can select the syslog facility from a combo-box. (Refer to the syslog man page for an explanation of this setting.) Usually the default LOCAL0 is satisfactory. The Toolbar currently has no provisions to make any adjustments to the syslog configuration files, so if changes are required the system administrator must do them manually.

You use the remaining options to select what should be logged. Only messages at or above the log level are logged; you can also ask that connections to the backend be logged and even that SQL commands be logged. In the latter case there are options to log the duration of the SQL command execution, which can be useful when debugging problems with queries. An additional option requests that all log entries be preceded by a timestamp.

Note that SQL logging (and logging in general) may generate a large volume of records so be careful when redirecting the backend log to the system's syslog facility.

	Note
	Control Center cannot display the syslog-generated files, but you can use the redhat-logviewer program to do this. (Control Center can only access files in /var/log/rhdb.)

When logging to /var/log/rhdb you may want to rotate the log files, limiting the size of such files, the number of versions, the frequency of rotation, and so on. The Rotation tab enables you to configure the system so that the logrotate utility is used for that purpose. These settings take effect only if the log is on and is sent to /var/log/rhdb.

	Warning
	Currently the backend is restarted when the log rotation is performed. This may affect applications that are using the database at that time. This limitation will be lifted in a future release.

The settings on the Rotation tab are related to the logrotate(8) utility; refer to that program's man page for further details.