When you’re using eXist day to day and eventually deploying it into a production environment, there are several topics that are useful to understand, both for those in a developer role and (even more so) for those in a system administration or DevOps role. In this chapter, we’ll look at some of the tools provided by or used with eXist that aid in ensuring stable and performant operation.
eXist uses Apache log4j as its mechanism for logging information and issues. Log4j provides a logging hierarchy that is configurable without changing the eXist code. Understanding how log4j works and how to configure it can help you get the most out of your eXist logfiles. Log4j provides several levels of logging. When eXist wishes to log a message, it decides at which level to log the message, and your log4j configuration then decides how that message is handled. The levels that log4j provides and at which eXist logs various messages are displayed in Table 15-1, with the most fine-grained at the top.
Used for tracing the execution of complex parts of the eXist code. It is very unlikely that you will need to receive log messages at this level, unless debugging a serious issue.
Similar to Trace, but less fine-grained. Again, it is very unlikely that you will need to receive log messages at this level unless you are investigating an issue with eXist.
Used for logging status information about eXist for ...