Contributed by Eric McCormack
The EnterpriseDB JDBC Driver supports the use of logging (or tracing) to help resolve issues with the JDBC Driver when is used in your application.
The JDBC Driver uses the logging APIs of
java.util.logging (part of Java since JDK 1.4), which makes it a good choice for the driver since it doesn't add any external dependency for a logging framework.
java.util.logging is a very rich and powerful tool, it's beyond the scope of this blog to explain or use its full potential, for that please refer to Java Logging Overview.
This logging support was added since version 22.214.171.124 of the EnterpriseDB JDBC Driver, while previous versions use a custom mechanism to enable logging that it is replaced by the use of
java.util.logging in current versions, the old mechanism is no longer available.
The Logging APIs offer both static and dynamic configuration control. Static control enables field service staff to set up a particular configuration and then re-launch the application with the new logging settings. Dynamic control allows for updates to the logging configuration within a currently running program.
As part of the support of a logging framework in the JDBC Driver, there was a need to facilitate the enabling of the Logger using connection properties, which uses a static control to enable the tracing in the driver. Keep in mind that if you use an Application Server (Tomcat, JBoss, WildFly, etc.) you should use the facilities provided by the application server to enable the logging, as most Application Servers use dynamic configuration control which makes easy to enable/disable logging at runtime.
The root logger used by the JDBC driver is com.edb.
Enable logging by using connection properties
The driver provides a facility to enable logging using connection properties, it's not as feature rich as using a
logging.properties file, so it should be used when you are really debugging the driver.
The properties are
loggerLevel: Logger level of the driver. Allowed values:
This option enables the
java.util.logging.Logger Level of the driver based on the following mapping:
As noted, there are no other levels supported using this method, and internally the driver Logger levels should not (for the most part) use others levels as the intention is to debug the driver and don't interfere with higher levels when some applications may enable them globally.
loggerFile: File name output of the Logger.
If set, the Logger will use a
java.util.logging.FileHandler to write to a specified file. If the parameter is not set or the file can't be created the will
java.util.logging.ConsoleHandler be used instead.
This parameter should be used together with
The following is an example of how to use connection properties to enable logging:
Enable logging by using logging.properties file
The default Java logging framework stores its configuration in a file called
logging.properties. Settings are stored per line using a dot notation format. Java installs a global configuration file in the
lib folder of the Java installation directory, although you can use a separate configuration file by specifying the
java.util.logging.config.file property when starting a Java program.
logging.properties files can also be created and stored with individual projects.
The following is an example of settings that you can make in the
# Specify the handler, the handlers will be installed during VM startup. handlers= java.util.logging.FileHandler # Default global logging level. .level= OFF # default file output is in user's home directory. java.util.logging.FileHandler.pattern = %h/edbjdbc%u.log java.util.logging.FileHandler.limit = 5000000 java.util.logging.FileHandler.count = 20 java.util.logging.FileHandler.formatter = java.util.logging.SimpleFormatter java.util.logging.FileHandler.level = FINEST java.util.logging.SimpleFormatter.format=%1$tY-%1$tm-%1$td %1$tH:%1$tM:%1$tS %4$s %2$s %5$s%6$s%n # Facility specific properties. com.edb.level=FINEST
And when you run your application you pass the system property:
java -jar -Djava.util.logging.config.file=logging.properties run.jar