Enabling enhanced tracing for JPA

In some situations the trace information generated by the Java™ Persistence API (JPA) providers shipped with WebSphere® Application Server may 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 will only function with IBM-shipped persistence providers. It will not work with 3rd party providers, including versions of OpenJPA bundled within an application or configured as a shared library.

About this task

Enabling enhanced tracing in a WebSphere Application Server environment

Enhanced JPA tracing for an application running on WebSphere Application Server can be enabled with a few simple steps using wsadmin scripting or the administration console. The steps below 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.

Procedure

  1. 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 Administration console by following these steps:
    1. In the navigation pane, select Servers. Select Application Servers.
    2. In the server list pane, select the server that needs the enhanced JPA trace. If multiple servers provide JPA functionality to your application, these steps must be followed for every server.
    3. Under the Server Infrastructure heading, select Java and Process Management. Select Process Definition.
    4. Under the Additional Properties heading, select Java virtual machine.
    5. Add the following argument to the Generic JVM arguments field, where <WAS install path> is the fully qualified path of your application server install directory. Make sure to use the path separator character appropriate for your operating system.
      -javaagent:<WASinstall path>/optionalLibraries/IBM/wsjpa/wsjpatrace.jar
  2. Enable additional trace components and adjust trace file options. You can accomplish this with wsadmin scripting or the Administration Console. These steps describe how to adjust trace file settings and enable components using the Administration Console:
    1. In the navigation pane, select Troubleshooting. Click Logs and Trace.
    2. Select the name of the server to trace.
    3. Under the General Properties heading, selectDiagnostic Trace.
    4. 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 extremely large.
    5. Under the Additional Properties heading, select Change Log Detail Levels.
      Important: The use of generic JVM arguments in the Administrative console does not currently support spaces within arguments. If spaces are specified in this field, the server may fail to start. This is more likely to occur in a Windows® environment because the default install path is C:\Program Files\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 <WAS install path>. For example, C:\Progra~1\IBM\WebSphere|AppServer. On Unix-type systems a symbolic link can be used to eliminate spaces in the <WAS install path>. For example, if the WebSphere Application Server installation path is /opt/WAS Install/AppServer, a symbolic link can be created in /opt from WAS Install to WASInstall, eliminating the space. Then, specify /opt/WASInstall/AppServer as the <WAS install path> in the generic JVM argument.
    6. Enable various extended trace categories by specifying one or more trace categories from the table below. 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.
      Table 1. Trace categories. Back up your server configuration before you enable enhanced tracing.
      Category Relevant trace levels Description
      JPA OFF, ALL, FINER, FINEST Adds 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.
  3. Save the application server configuration and restart the application server.

Results

After you restart the application server, the new trace settings are picked up.

What to do next

Note: 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.



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Last updated: Oct 20, 2010 7:53:43 PM CDT
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