Enable enhanced tracing for JPA

Enable enhanced tracing for JPA

In some situations the trace information generated by the Java Persistence API (JPA) providers shipped with WebSphere Application Server might not be adequate to diagnose a problem. In these situations, an extended trace mechanism can be enabled to generate additional information in the trace file. Extended trace can function only with IBM-shipped persistence providers. It does not work with third-party providers, including alternate versions of OpenJPA bundled within an application or configured as a shared library.

This topic references one or more of the application server log files. As a recommended alternative, we can configure the server to use the High Performance Extensible Logging (HPEL) log and trace infrastructure instead of using SystemOut.log , SystemErr.log, trace.log, and activity.log files on distributed and IBM i systems. We can also use HPEL in conjunction with the native z/OS logging facilities. If we are using HPEL, we can access all of the log and trace information using the LogViewer command-line tool from the server profile bin directory. See the information about using HPEL to troubleshoot applications for more information on using HPEL.
Enhanced JPA tracing for an application running on WAS can be enabled with a few simple steps using wsadmin scripting or the administration console. The steps in this topic describe how to configure enhanced tracing using the administration console. This process changes server settings, so it is good practice to back up your server configuration before proceeding.

Enable the trace agent. A trace agent must be enabled per application server by passing an argument to the server Java Virtual Machine (JVM). The trace agent can be enabled using the console by following these steps:

In the navigation pane, select Servers. Select Application Servers.

In the server list pane, select the server that needs the enhanced JPA trace. If multiple servers provide JPA functionality to the application, these steps must be followed for every server.

Under the Server Infrastructure heading, select Java and Process Management. Select Process Definition.

Under the Additional Properties heading, select Java virtual machine.

Add the following argument to the Generic JVM arguments field, where <app_server_root> is the fully qualified path of the application server installation directory. Make sure to use the path separator character appropriate for your operating system.
-javaagent:app_server_root/optionalLibraries/IBM/wsjpa/wsjpatrace.jar

Important: The use of generic JVM arguments in the console does not currently support spaces within arguments. If spaces are specified in this field, the server can fail to start. This is more likely to occur in a Windows environment because the default installation path is C:\IBM\WebSphere\AppServer, which contains a space in the path. To work around this problem in a Windows environment use an abbreviated path name for the <app_server_root>. For example, C:\Progra~1\IBM\WebSphere|AppServer. On UNIX-type systems a symbolic link can be used to eliminate spaces in the <app_server_root>. For example, if the WAS installation path is/opt/app_server_root/AppServer, a symbolic link can be created in /opt from <app_server_root> to AppServerRoot, eliminating the space. Then, specify /opt/AppServerRoot/AppServer as the <app_server_root> in the generic JVM argument.

Enable additional trace components and adjust trace file options. We can accomplish this step with wsadmin scripting or the administration console. These steps describe how to adjust trace file settings and enable components using the administration console:

In the navigation pane, select Troubleshooting. Click Logs and Trace.

Select the name of the server to trace.

Under General Properties, select Diagnostic Trace.

Make sure Enable Log is checked and optionally increase the Maximum File Size and Maximum Number of Historical Files. Depending on the number of additional trace categories and the trace levels chosen, the trace file can become large.

Under the Additional Properties heading, select Change Log Detail Levels.

Enable various extended trace categories by specifying one or more trace categories from the following table. An example trace string is: *=info:JPA=all:openjpa.*=finer:openjpa.kernel=finest. Extended trace traces at the FINER or FINEST trace levels. The FINEST level includes more detail than FINER. When ALL is specified, extended trace traces at the FINEST level.

Category Relevant trace levels Description
JPA OFF, ALL, FINER, FINEST Add extended trace to the JPA trace group.
openjpa.* OFF, ALL, FINER, FINEST Normal OpenJPA trace in addition to extended trace for all categories in OpenJPA when extended trace is enabled.
openjpa.xtrace.* OFF, ALL, FINER, FINEST Extended trace for all categories in OpenJPA when extended trace is enabled.
openjpa.xtrace.Jdbc OFF, ALL, FINER, FINEST Extended trace for OpenJPA JDBC classes when extended trace is enabled.
openjpa.xtrace.Lib OFF, ALL, FINER, FINEST Extended trace for OpenJPA library classes when extended trace is enabled.
openjpa.xtrace.Persist OFF, ALL, FINER, FINEST Extended trace for OpenJPA persistence classes when extended trace is enabled.
openjpa.xtrace.Kernel OFF, ALL, FINER, FINEST Extended trace for OpenJPA kernel classes when extended trace is enabled.
openjpa.xtrace.General OFF, ALL, FINER, FINEST Extended trace for OpenJPA classes not included in the JDBC, Lib, Persist, or Kernel categories when extended trace is enabled.
openjpa.xtrace.ApiSpi OFF, ALL, FINER, FINEST Extended trace for public API/SPI interfaces defined for WsJPA, OpenJPA, and JPA when extended trace is enabled.

Save the application server configuration and restart the application server.

Results
After you restart the application server, the new trace settings are used.

What to do next

Avoid trouble: Tracing can degrade performance significantly and should be disabled when not in use. To disable trace, remove the Generic JVM argument and any trace detail levels added for enhanced tracing.gotcha

Related tasks

Logging applications with JPA

Category	Relevant trace levels	Description
JPA	OFF, ALL, FINER, FINEST	Add extended trace to the JPA trace group.
openjpa.*	OFF, ALL, FINER, FINEST	Normal OpenJPA trace in addition to extended trace for all categories in OpenJPA when extended trace is enabled.
openjpa.xtrace.*	OFF, ALL, FINER, FINEST	Extended trace for all categories in OpenJPA when extended trace is enabled.
openjpa.xtrace.Jdbc	OFF, ALL, FINER, FINEST	Extended trace for OpenJPA JDBC classes when extended trace is enabled.
openjpa.xtrace.Lib	OFF, ALL, FINER, FINEST	Extended trace for OpenJPA library classes when extended trace is enabled.
openjpa.xtrace.Persist	OFF, ALL, FINER, FINEST	Extended trace for OpenJPA persistence classes when extended trace is enabled.
openjpa.xtrace.Kernel	OFF, ALL, FINER, FINEST	Extended trace for OpenJPA kernel classes when extended trace is enabled.
openjpa.xtrace.General	OFF, ALL, FINER, FINEST	Extended trace for OpenJPA classes not included in the JDBC, Lib, Persist, or Kernel categories when extended trace is enabled.
openjpa.xtrace.ApiSpi	OFF, ALL, FINER, FINEST	Extended trace for public API/SPI interfaces defined for WsJPA, OpenJPA, and JPA when extended trace is enabled.