Configuring the Logging Engine

Virtual DataPort uses the logging library Apache Log4j 2 to log the activity of the Virtual DataPort server and Apache Log4j 1.x to log the activity of the other components. Log4j allows defining several categories on which the log level will be specified independently. For each category, the log level can be TRACE, DEBUG, INFO, WARN, ERROR or FATAL.

The Virtual DataPort Server logs are stored in <DENODO_HOME>/logs/vdp and the Administration Tool logs, in <DENODO_HOME>/logs/vdp-admin.

The configuration of Log4j of the Virtual DataPort server is controlled by the file <DENODO_HOME>/conf/vdp/log4j2.xml; for the administration tool by <DENODO_HOME>/conf/vdp-admin/log4j.xml.

You need some knowledge of Log4j to modify these configuration files. Their syntax is different because the Server uses Log4j version 2 and the other components, Log4J version 1.

To apply the changes made on log4j2.xml or log4j.xml, you have to restart the Server or the administration tool respectively.

You can change the log level of a category in the Server without restarting by doing the following:

  1. Invoking the stored procedure LogController. See more about this in the section LogController of the VQL Guide.

  2. Or, invoking the operation setLogLevel of the LogManagementInfo MBean. See more about this operation in the section LogManagementInfo MBean.

The changes in the log levels performed at runtime are lost when the Server is restarted.


In production environments, we recommend using an ERROR log level. Lower levels degrade the system performance and are only recommended for debugging tasks.

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