Java Heap Dump

1、java heap dumpquestion how do you lect a tbsm server jvm heap dump? answer options for getting java heap dump 1) request java to dump heap on an out of memory error a the following to the jvm tings: -xx:+heapdumponoutofmemoryerror -xx:+heapdumponoutofmemoryerror this option available in 1.5.0_07 and

2、 1.4.2_12, procing an hprof binary foat heap hprof heap dumps are platform independent and so you dont ne to analyze the dump on the same system that produced it running with -xx:+heapdumponoutofmemoryerror does not impact performae - it is simply a flag to indie that a heap dump should be generated

3、 when the first thread throws outofmemoryerror. optional ao: -xx:heapdumppath= -xx:heapdumppath specifies path to directory or name for heap dump. (inoduced in 1.4.2 up 12, 5.0 update 7.) path to filename for heap dump, i.e. -xx:heapdumppath=/some/directory/filename.hprof note: on windows, the jvm c

4、an stay trashing (running garbage collections) before it actually reports an oom.2) force a heap dump, on demand (unix only) on unix, add the following to the jvm settings: -xx:+heapdumponctrlbreak this was available on unix in beginning with sdk 1.4.2.11 and jdk 1.5.0.05. then do: -quit p where is

5、pid is the running java process for the application. in 4.1.1, the command dumps the data into a tt file in $nchome. you may do a : . -name javacore* inside $nchome. if using tbsm 4.2 or 4.2.1 the heap dump should be created in the hope directory of the profile i.e. $tip_home/profiles/tbsmprofile or

6、 $tip_home/profiles/tipprofile note: kill -quit is equivilant to kill -3 and kill -sigquit note: for windows -xx:+heapdumponctrlbreak was only introduces in 1.5.0_14. this is above the release of java in tbsm 4.2.1 (1.5.0 sr 11) so this option is not possible in current tbsm versions on windows.3) u

7、sing ewas (tbsm 4.2 and 4.2.1) you can get a full jvm heap dump uses ewas. note, that this is only works in linux , windows, and aix. $tip_home/bin/wsadmin -username tipadmin -password tipadmin password the script will take you to the was admin prompt: for impact: wsadmin set objectname $admincontro

8、l querynames websphere:type=jvm,process=server1,node=impactnode,* for data server wsadmin set objectname $admincontrol querynames websphere:type=jvm,process=server1,node=tbsmnode,* for dashboard server wsadmin set objectname $admincontrol querynames websphere:type=jvm,process=server1,node=tipnode,*

9、this command will set up the variable objectname, then in the prompt invoke it: wsadmin $admincontrol invoke $objectname generateheapdump the command will dump the heap as .phd file in $tip_home/profiles/tbsmprofile or $tip_home/profiles/tipprofile. it should give you the full path and name of the f

10、ile. note: that in linux if the application goes out of memory, it dump the above 2 steps by default. in solaris, you have to specify it in a script.4) jconsole you could utilize jconsole by calling the hotspotdiagnostic mbean and the dumpheap operation if its available from your sun jvm. note: jcon

11、sole is not shipped with the jre in tbsm. you will need to install the 1.6 java jdk for jconsole. 1.6 jdk can be installed on a client machine and can connect remotely to the tbsm jvm if the following startup jvm options are set for tbsm. jconsole from 1.6 jdk can connect to earlier version of jvm,

12、i.e. s like you can use a 1.5 sun jdks jconsole to connect to a sun 1.4.2 jvm: tstart=180 . you can run jconsole on jdk 5.0 and still connect to an application running on jdk 1.4.2. you will get access to your application mbeans through the mbeans tab but you wont get access to the m m tabs and plat

13、form mbeans as they didnt exist in jdk 1.4.2. if you need to access m m tabs (threads, memory usage etc.), your application have to run on jdk 5.0, started with -dcom.n.management.jmxremote java option. set the following options: -dcom.sun.management.jmxremote.port=8086 -dcom.sun.management.jmxremot

14、e.ssl=false -dcom.sun.management.jmxremote.authenticate=false see link for information to open jconsole (just type jconsole), and go to the mbeans tab. in the left hand structure look for the following er; com.sun.management. expand and click on hotspotdiagnostic. in the right hand window click on o

15、perations. there should be an option to dump the heap memory.5) jmap (only for version 1.6 on windows) jmap prints shared object memory maps or heap memory details of a given process or core file or a remote debug server. this is not available on the jre shipped with tbsm. for this (like jconsole) the jdk is required. it is available on version 1.5 for linux and 1.6 for windows jdk. usage: jmap -histo pid (to print histogram of java object heap of the jvm process) jmap -dump: dump-options pid (to dump java heap of the jvm process) dump-options: format=b binary default file= fi