There is an update about the available databases that support XML. Of those, there's quite a few open source ones:
log4j 1.2 beta 3:
In addition to many performance improvements, bug fixes, and other small enhancements, log4j 1.2 beta3 adds JMX support, Mapped Diagnostic Contexts, and buffered IO capability. One important change is the replacement of the Category class with Logger class and the Priority with the Level in order to facilitate migrating from the JDK 1.4 logging API to log4j.
All changes except the removal of deprecated methods are backward compatible such that log4j 1.2beta3 can be considered a drop in replacement for log4j 1.1.3.