Known limitations

The Health Center client and agent applications have known limitations on their use and operation.

Health Center client

GUI updates are batched internally. The GUI might become unresponsive for a time, while it is waiting for an update.

While it is running, the Health Center client writes temporary files, healthcenter [xxxx] Source [xxxx].tmp, to your temporary directory. Delete these files manually.

For IBM® SDK, Java™ Technology Edition, Version 5 service refresh 9 and earlier or Version 6 service refresh 4 and earlier, if a previous connection was made to the agent, you can view method names only for classes that were loaded since the previous client was disconnected.

Health Center agent Version 3.0 and later in IBM SDK for Linux on System i and System p architecture, Java Technology Edition, Version 6

Versions 3.0 and later of the Health Center agent do not run in IBM SDK for Linux on System i® and System p architecture, Java Technology Edition, Version 6, service refreshes 1 through 9. This limitation is due to the following issue in the SDK: IV02046: C++ ABI COMPATIBILITY BREAK ON PLINUX INTRODUCED BY THE INTRODUC TION OF C++ CODE IN JAVA 6 ON PLINUX.

If you are using a version of the SDK at these levels, do not upgrade your Health Center agent. Alternatively, upgrade your version of IBM SDK, Java Technology Edition to at least Version 6, service refresh 10, before you upgrade Health Center.

Health Center agent temporary file (Java applications only)

If you started the Health Center agent with the -Xtrace:output=<filename> option, you must manually delete the file after the application ends.

Running the agent in headless mode (Java applications only)

Missing method names

When you run in headless mode, you might find that some method names in the method profiling view are missing. This result is a current limitation of operating in this mode. This limitation applies to IBM SDK and Runtime Environment, Java Technology Edition, Version 6 Service Refresh 10 and earlier.

To mitigate this problem, specify the -Xtrace:buffers={128k,dynamic} parameter in the command that you use to start the monitored application. This solution reduces the problem, but might not fix it completely.

Application does not end correctly

If your application does not end correctly, the problem might be due to essential activities that are taking place when your program exits. These activities include cleaning up temporary files and creating the headless import file. You can avoid this problem by sending a termination signal to your application. This limitation typically affects commands such as java -version when you are running in headless mode.

Running the agent in inprocess mode

If you use Java Management Extensions (JMX) while you are running the Health Center agent in inprocess mode, do not specify the -Dcom.sun.management.jmxremote JMX parameter. If you use this parameter, Health Center fails to start, and a javax.management.InstanceNotFoundException exception is thrown. For more information, see javax.management.InstanceNotFoundException exception when you use JMX and inprocess mode.

Setting the maximum stack depth in the healthcenter.properties file

If you use the com.ibm.java.diagnostics.healthcenter.thread.stack.depth property to set the maximum stack depth to be something other than the default of 5, the value is used, but not shown in the client. The health center client shows the default value of 5 even though it reports the depth that you set in the properties file.

Monitoring an IBM Bluemix application

When monitoring applications that are running in the Liberty for Java or SDK for Node.js runtime environments in Bluemix®, the ability to write verbose garbage collection data to a file does not currently work.





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