java - 从核心转储中提取堆转储 (hprof)

Question

目前我有一个核心转储文件，我想提取堆转储。无论我尝试什么，我总是会收到以下错误消息:

god@heaven:~$ sudo /opt/java-MyApp/bin/jmap -dump:format=b,file=my-file.hprof /opt/java-MyApp/bin/java /home/god/tmp/core
[sudo] password for god: 
Attaching to core /home/god/tmp/my-app-core-dump from executable /opt/java-MyApp/bin/java, please wait...
Error attaching to core file: Doesn't appear to be a HotSpot VM (could not find symbol "gHotSpotVMTypes" in remote process)
sun.jvm.hotspot.debugger.DebuggerException: Doesn't appear to be a HotSpot VM (could not find symbol "gHotSpotVMTypes" in remote process)
    at sun.jvm.hotspot.HotSpotAgent.setupVM(HotSpotAgent.java:411)
    at sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:305)
    at sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:156)
    at sun.jvm.hotspot.tools.Tool.start(Tool.java:191)
    at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118)
    at sun.jvm.hotspot.tools.HeapDumper.main(HeapDumper.java:83)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at sun.tools.jmap.JMap.runTool(JMap.java:201)
    at sun.tools.jmap.JMap.main(JMap.java:130)

如果我尝试用 gdb 打开核心，它就像一个魅力:

gdb --core core
GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.04) 7.11.1
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
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For help, type "help".
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[New LWP 11241]
[New LWP 11242]
[New LWP 11243]
[New LWP 11244]
[New LWP 11245]
...
[New LWP 23423]
[New LWP 30560]
[New LWP 11240]
Core was generated by `/opt/java-MyApp/bin/java -Djava.util.logging.config.file=/opt/MyAp'.
#0  0x0000003c838cc0a6 in ?? ()
[Current thread is 1 (LWP 11241)]
(gdb) 

从我读过的所有内容来看，我应该确保将 JVM 安装在与使用 {{gcore}} 完成核心转储时相同的路径和版本上。完成后，我需要做的就是用那个确切的 jvm 调用 jmpa:

sudo $JVM_USED_WHILE_GCORE_HOME/bin/jmap -dump:format=b,file=$OUTPUT_HPROF_FILE $JVM_USED_WHILE_GCORE_HOME/bin/java $CORE_FILE_PATH

有什么我想念的吗？为什么我总是收到“在远程进程中找不到符号“gHotSpotVMTypes””错误消息？

Answer 1

问题很简单。 /opt/java-MyApp/bin/java 路径是一个符号链接(symbolic link)，一旦我重新创建了我在用于生成核心转储的机器上的结构它就像一个魅力。这些库似乎是按其规范路径使用的。