I want to take a thread dump of my java - Jmeter machine. In my Jmeter machine I can see many of the threads are not closed and stucked after test timings. To debug more I tried to take thread dump(using "jstack -PID>>Fileae.txt" command). but this command is still running after 24Hrs, although this has created a empty textfile.
Why I am not able to take a thread dump of that java process.
Try this -
‘jstack’ is an effective command line tool to capture thread dumps. jstack tool is shipped in JDK_HOMEbin folder. Here is the command that you need to issue to capture thread dump:
jstack -l >
where
pid: is the Process Id of the application, whose thread dump should be captured
file-path: is the file path where thread dump will be written in to.
Example:
jstack -l 37320 > /opt/tmp/threadDump.txt
As per the example thread dump of the process would be generated in /opt/tmp/threadDump.txt file.
Jstack tool is included in JDK since Java 5. If you are running in older version of java, consider using other options.
Related
In our web application deployed on tomcat, catalina.out file keeps growing (it grows in GB's).
So to disable it I found solution where I set CATALINA_OUT=/dev/null.
This worked as expected but we also use kill -3 <PID> command to capture Thread Dump whenever it requires.
This thread dump gets written into catalina.out file but now I have disabled catalina.out so I cannot see thread dump.
How can I get thread dump?
Since it is a production system therefore we are using JRE and not JDK otherwise we would have used jmap/jcmd/jstack commands to capture thread dump.
So, I would like, tomcat should stop creating catalina.out file or do not write log4j statements in it. And if it is disabled then how to get thread dump?
Finally I found the solution which I was looking for. I added below lines of statement in tomcat/bin/startup.sh file
export CATALINA_OUT=/dev/null
export JAVA_OPTS="$JAVA_OPTS -XX:+UnlockDiagnosticVMOptions -XX:+LogVMOutput -XX:LogFile=thread_dump.log"
CATALINA_OUT set to /dev/null will stop writing log statements in catalina.out log.
JAVA_OPTS -XX:+UnlockDiagnosticVMOptions -XX:+LogVMOutput -XX:LogFile=thread_dump.log configurations is used to write thread dump statements generated using kill –3 <PID> command. It will also print JVM-related configuration being used.
I hope this will help someone.
I have an issue about continuously running Java Flight Recorder to monitor memory usage and other performance statistics of ActiveMQ.
Wrapper configuration file (wrapper.conf) is under this directory with nearside (wrapper, activemq, libwrapper.so) files;
../apache-activemq-5.12.1/bin/linux-x86-64/wrapper.conf
I added the lines below to run JFR;
wrapper.java.additional.13=-XX:+UnlockCommercialFeatures
wrapper.java.additional.14=-XX:+FlightRecorder
wrapper.java.additional.15=-XX:FlightRecorderOptions=defaultrecording=true,disk=true,repository=../jfr/jfrs_%WRAPPER_PID%,settings=profile
wrapper.java.additional.16=-XX:StartFlightRecording=filename=../jfr/jfrs_%WRAPPER_PID%/myrecording.jfr,dumponexit=true,compress=true
When I run wrapper file, expected output 'myrecording.jfr' is generated under specified path in wrapper.conf. But the problem is, I also want it to be happen automatically (without running wrapper file by hand).
What might be the possible solution for that?
I am currently setting up a web service powered by apache and running on CENTOS 6.4.
This service uses perl scripts (cgi-bin) launching in particular external homemade fortran compiled binaries.
Here is the issue: when I boot my server, everything goes well except that one of my binary crashes systematically (with a kernel segfault) when called by my perl scripts.
If I restart manually the httpd service (at the command line: service httpd restart), the issue is totally fixed.
I examined apache/system logs and nothing suspicious can be found.
It appears that the problem occurs only when httpd is launched by /etc/rc[0-6].d startup directives. I tried to change the launch order of http (S85httpd by default) to any other position without success.
To summarize, my web service is only functional (with no external binary crash) when httpd is launched at the command line once the server has fully booted up!
[EDIT] This issue is now resolved:
My fortran binary handles very large arrays and complex functions requiring an unlimited stack size.
Despite that the stack size limit was defined on a system-wide basis (in /etc/security/limits.conf), for any reason it appears that the "apache/perl/fortran binary" ensemble was not aware of that (causing my binary to crash each time it was called).
At the contrary, when I manually restarted apache at the shell prompt, the stacksize limit was correctly passed (.bashrc with 'ulimit -S -s unlimited').
As a workaround, I used BSD::Resource module (http://metacpan.org/pod/BSD::Resource) to define stacksize directly in my perl script by using e.g. setrlimit(RLIMIT_STACK, $softlimit, $hardlimit);
Thus, this new stack size limit is now directly passed from my perl script to my binary.
I've run into similar problems before. Maybe one way to solve this is to put the binary on a 'delayed start', so that it starts after everything else on your system is running. One way to do this is to put an at job in your /etc/rc.local script, to start the binary in X minutes.
Glassfish v3 is launched as follows:
./bin/asadmin start-domain <domain-name>
This script eventually runs:
exec "$JAVA" -jar "$AS_INSTALL_LIB/admin-cli.jar" "$#"
admin-cli.jar eventually launches another process, effectively putting itself into the background.
I would like to launch glassfish without putting itself in the background for the purpose of monitoring with daemontools (ie: svc). Is this possible?
The documentation talks about using inittab here which seems like it would also require a way to launch it without forking or backgrounding so some other process (eg: inittab, evc, etc.) can watch the process id and restart it if it crashes. However, in this inittab example, is it using the same backgrounding cmd line, so I don't know how inittab can possibly respawn the process when it doesn't know what process id to watch. Am I missing something?
You should be able to use asadmin start-domain -v...
Note: log statements are sent to the log file AND System.out/System.err.
hi i am new to valgrind. I know how to run valgrind on executable files from command line. But how do you run valgrind on server processes like apache/myqld/traffic server etc ..
I want to run valgrind on traffic server (http://incubator.apache.org/projects/trafficserver.html) to detect some memory leaks taking place in the plugin I have written.
Any suggestions ?
thanks,
pigol
You have to start the server under Valgrind's control. Simply take the server's normal start command, and prepend it with valgrind.
Valgrind will attach to every process your main "server" process spawns. When each thread or process ends, Valgrind will output its analysis, so I'd recommend piping that to a file (not sure if it comes out on stderr or stdout.)
If your usual start command is /usr/local/mysql/bin/mysqld, start the server instead with valgrind /usr/local/mysql/bin/mysqld.
If you usually start the service with a script (like /etc/init.d/mysql start) you'll probably need to look inside the script for the actual command the script executes, and run that instead of the script.
Don't forget to pass the --leak-check=full option to valgrind to get the memory leak report.