Logging

The Fusion Metadata Registry logs information regarding the requests made to it and the work that it is performing. These logs can be long and complicated, but this document aims to explain the logging process.

Logging information is stored in the filesystem as well as in database tables. The files on your system are possibly more transient so unless you take action these will likely be replaced with more recent log information. This is to prevent the size of the log files consuming all of your disk space.

File-based logging

The actual logs generated are controlled by a system setting in the FMR which directly relates to the logging tool that the FMR uses, which is called Logback. The actual files generated are also affected by the Java Web-Application Server you are running (for example Apache Tomcat).

While log files often convey useful information, they naturally grow bigger over time. If allowed to grow indefinitely, their size could become a problem.

Logging libraries address this problem using rolling file appenders, which automatically “roll” or archive the current log file, and resume logging in a new file when certain predefined conditions occur, thereby preventing unwanted downtime.

Database Logging

There are also log tables within the database which persist some of this information.

• Log Tables
• Audit Tables