The SAS Logging Facility

Logging Thresholds

The SAS logging facility provides six thresholds: TRACE, DEBUG, INFO, WARN, ERROR, and FATAL. Thresholds are used to ignore log events that are lower than a particular level, or to filter messages so that only a single message level is logged.

When a log event occurs, up to three levels of filtering can take place:

filtering log events by comparing the log event level to the log event's logger level
filtering log events by comparing the log event level to the appender's threshold
filtering log events by comparing the log event level to the threshold that is specified in the filter definition, which is a part of the appender configuration

In the first two cases, if the log event level is lower than the logger or appender threshold, the logging facility ignores the log event. Otherwise, processing of the log event continues.

In the third case, the log event level is compared to the filter threshold. If there is a match, the log event can be either accepted or denied. If there is no match, the filtering process continues to the next filter in the filtering policy. For more information, see Filters.

The logging levels, from the lowest to the highest, are as follows:

TRACE	produces the most detailed information about your application. This level is primarily used by SAS Technical Support or development.
DEBUG	produces detailed information that you use to debug your application. This level is primarily used by SAS Technical Support or development.
INFO	provides information that highlights the progress of an application.
WARN	provides messages that identify potentially harmful situations.
ERROR	provides messages that might allow the application to continue running.
FATAL	provides messages that indicate that severe errors have occurred. These errors will probably cause the application to end.

Requirement: The level must be enclosed in quotation marks.

An appender can be configured to have a threshold. By default, however, appenders do not have a threshold. When set, all log events that have a level lower than the threshold are ignored by the appender.

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