4.7.3 When using JavaVM commands
When using the JavaVM commands, you can acquire the class-wise statistical information or Explicit heap detail information with the extended thread dump.
- Organization of this subsection
(1) Acquiring an extended thread dump of class-wise statistical information
Execute the jheapprof command to acquire an extended thread dump of the class-wise statistical information. The class-wise statistical information is output using the class-wise statistic functionality, and this information is used for changing Java objects and checking the Java object reference depending on the GC. For details about the class-wise statistical functionality, see the section 9.3 Class-wise statistical functionality and for details about how to output the class-wise statistical information, see the subsection 9.3.3 Outputting Statistic Information for Each Class. For the jheapprof command, see jheapprof(Output of extended thread dump containing Hitachi class-wise statistical information) in the uCosminexus Application Server Command Reference Guide.
(2) Acquiring an extended thread dump of Explicit heap detail information
Among the Explicit heap detail information, if the Explicit Memory Management functionality is valid, acquire the following information in the extended thread dump:
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Explicit heap information
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Explicit memory block information
Acquire the object statistical information of the Explicit heap detail information and the release rate information of the Explicit memory block with the extended thread dump by executing the eheapprof command. The object statistical information is the detailed information in Explicit memory blocks. The release rate information is the ratio of objects released in the automatic release processing of the Explicit memory block. This information is used for debugging and for error analysis of the system that uses the Explicit Memory Management functionality.
For details about the Explicit Memory Management functionality, see 7. Suppression of Full GC by Using the Explicit Memory Management Functionality in the uCosminexus Application Server Expansion Guide. For details about the eheapprof command, see eheapprof (Output of extended thread dump containing the Explicit heap detailed information) in the uCosminexus Application Server Command Reference Guide.
- Execution format
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In Windows
eheapprof [-f|-i] [-freeratio] -p process-ID
In UNIX
eheapprof [-f|-i] [-freeratio] [-force] -p process-ID
- Execution example
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Here, the class-wise statistical information of Java process with process ID 2463 is output.
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In the -p option, specify the process ID of Java process to output class-wise statistical information and then execute the eheapprof command.
% eheapprof -p 2463
When the -f option is omitted using the eheapprof command, the following confirmation message is displayed:
- In Windows
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The confirmation message whether to output an extended thread dump with Hitachi class-wise statistical information is displayed in the following format:
Force VM to output ExplicitHeapProf: ? (y/n)
- In UNIX
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Confirmation message of process ID is displayed in the following format:
send SIGQUIT to 2463: ? (y/n)
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Enter y
If the extended thread dump with Hitachi class-wise statistics is output, the following message is output in the running java program:
Writing Java core to javacore2463.030806215140.txt... OK
The running java program creates an extended thread dump with Hitachi class-wise statistics (javacore<process ID>.<date-time>.txt) in the current directory to continue the program.