Arthas simple instructions

Arthas Simple instructions for use

link ：
# Jdk VisualVM Use 、 Threads dump Make analysis
# Idea debugging Debug skill
Arthas Official documents

Arthas

• Arthas yes Alibaba stay 2018 year 9 Open source in Java The diagnosis Tools . Support JDK6+, Use command line interaction mode , Provide Tab Not fully automatic , It is convenient to locate and diagnose online program running problems .

Arthas Use scenarios

• Is there a global perspective to see the health of the system ？
• Why? CPU It's going up again , Where did it take up CPU ？
• Does the multithread running have a deadlock ？ Is there a jam ？
• The program takes a long time to run , Where does it take longer ？ How to monitor ？
• Where does this class come from jar Package loaded ？ Why do you report all kinds of related Exception？
• Why didn't I change the code to ？ I didn't commit？ The branch is wrong ？
• I can't get online when I have a problem debug, Can't we just add logs and redistribute them ？
• Is there any way to monitor JVM The real-time running state of ？

Installing the

• download : wget https://alibaba.github.io/arthas/arthas-boot.jar

• Download from image ：https://arthas.aliyun.com/download/latest_version?mirror=aliyun

• start-up : java -jar arthas-boot.jar

• Web Console：http://127.0.0.1:8563/)： The operation mode on the page is exactly the same as the console .

Relevant command

command	Introduce
dashboard	Real time data panel of current system
thread	View the current JVM Thread stack information for
watch	Methods perform data observation
trace	Method internal call path , And output the time consumption of each node on the method path
stack	Output the call path of the current method to be called
tt	Method to execute the spatiotemporal tunnel of data , Record the input and return information of each call of the specified method , And can observe these different time adjustments
monitor	Method execution monitoring
jvm	View the current JVM Information
vmoption	see , to update JVM Diagnosis related parameters
sc	see JVM Loaded class information
sm	View method information for loaded classes
jad	Decompile specifies the source code of the loaded class
classloader	see classloader Inheritance tree of ,urls, Class loading information
heapdump	similar jmap Ordered heap dump function

Common operations

• Use dashboard Command can overview the program's Threads 、 Memory 、GC、 Operating environment information .
• Use thread see all Thread information , The... Of each thread will also be listed CPU Usage rate

Thread

Parameter name	Parameter description
id	Threads id
[n:]	Before you designate the busiest N Thread and print stack
[b]	Find out which threads are currently blocking other threads
[i <value>]	Appoint cpu Sampling interval for usage statistics , The unit is millisecond , The default value is 200
[--all]	Show all matching threads

thread -b Find the deadlock thread

• thread --state blocked

• thread -b

The busiest before N Thread and print stack

• thread -n 3

Decompile class

• Decompile specifies the source code of the loaded class , Check whether the code in the current environment is the latest code

• jad com.li.springbootproject.service.thread.impl.ThreadTestServiceImpl

• Output to directory ：jad --source-only com.li.springbootproject.service.user.impl.UserServiceImpl > J://Documents//Desktop//UserServiceImpl.java
  

View class related properties

• see JVM Loaded class information

• sc -d -f com.li.springbootproject.service.thread.impl.ThreadTestServiceImpl
  

Look at the value of the variable

• ognl '@com[email protected]hashSet'

• Static variables modify values ：ognl '@com[email protected]hashSet.add("test")'

The viewing method takes time

class-pattern	Class name expression matching
method-pattern	Method name expression matching
condition-express	Conditional expression
[E]	Turn on regular expression matching , The default is wildcard matching
[n:]	Command execution times
#cost	Method execution time

• Use trace The command can track the statistics method time consuming

• trace com.li.springbootproject.service.test.impl.CommonServiceImpl insertDemo
  

Method execution monitoring

Monitoring item	explain
timestamp	Time stamp
class	Java class
method	Method （ Construction method 、 Common method ）
total	Call the number
success	Number of successes
fail	Number of failures
rt	Average RT
fail-rate	Failure rate

• monitor -c 5 com.li.springbootproject.controller.test.CommonController test

Observation method information

• Call path ：stack com.UserServiceImpl mysql

Find the corresponding class classloader

• sc -d *ThreadTestServiceImpl | grep classLoader

Idea install Arthas plug-in unit

• Installing this plug-in can quickly copy related commands