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Installation

Installation:

Wget https://alibaba.github.io/arthas/arthas-boot.jarjava-jar arthas-boot.jar

Execute directly under linux, and execute after window downloads the file.

After the execution is completed, the running java process in the JDK specified in the current path is displayed. Enter the corresponding sequence number and enter the sh command to indicate that the connection is successful.

Preliminary use

The initial use of the Arthas command can be divided into five categories:

Basic command

Help-- View Command help Information

Cat-- prints the contents of the file, similar to the cat command in linux

Pwd-- returns the current working directory, similar to the linux command

Cls-- clears the current screen area

Session-- to view information about the current session

Reset-- reset enhanced classes, all enhanced classes enhanced by Arthas will be restored, and all enhanced classes will be reset when the Arthas server is closed.

Version-- outputs the Arthas version number loaded by the current target Java process

History-- print Command History

Quit-- exits the current Arthas client, and other Arthas clients are not affected

Shutdown-- closes the Arthas server, and all Arthas clients exit

List of keymap--Arthas shortcut keys and custom shortcut keys

Jvm correlation

Real-time data panel of dashboard-- current system

Thread-- views the thread stack information of the current JVM

Jvm-- to view the current JVM information

Sysprop-- views and modifies the system properties of JVM

Sysenv-- views the environment variables of JVM

Getstatic-- looks at the static properties of a class

New! Ognl-- executes ognl expressions

New! Mbean-- views Mbean's information

Class/classloader correlation

Sc-- to view class information loaded by JVM

Sm-- to view method information for loaded classes

Jad-- decompilation specifies the source code of the loaded class

Mc-- memory compiler, memory interpretation. java files are .class files

Redefine-- loads external .class files and redefine them into JVM

Dump--dump has loaded the byte code of the class to a specific directory

Classloader-- to view the inheritance tree of classloader, urls, class loading information, use classloader to getResource

Monitor/watch/trace correlation

Please note that these commands are implemented through bytecode enhancement technology, and some aspects are inserted into the methods of the specified class to achieve data statistics and observation, so when online and pre-sent, please try to be clear about the classes, methods and conditions that need to be observed, and execute shutdown or enhanced classes to execute reset commands at the end of diagnosis.

Monitor-- method execution monitoring

Watch-- method performs data observation

The internal call path of the trace-- method and the output time on each node on the method path

Stack-- outputs the calling path where the current method is called

The tt-- method performs the spatio-temporal tunnel of the data, records the input parameters and return information of each call of the specified method, and can observe these different time calls.

Options

Options-- view or set Arthas global switch

Use real columns

Trace analyzes the specific execution time of each method

The figure shows that when calling the MongoTemplate.executeFindMultiInternal () method, the most time-consuming method is in the doWith () method, which is executed a total of 10000 times, with a total time of 252.3064ms. At least one call takes time = 0.0132ms, and the maximum time is 38.4329ms. The reason for the analysis is that the amount of data is too large, and MongoTemplate is serializing the results through loop traversal.

Jad decompiler code tool

Jad com.sankuai.inf.leaf.common.ZeroIDGen

Watch to view input and output parameters

Watch com.sankuai.inf.leaf.server.service.SegmentService getId'{params, target, returnObj}'- x 2

Params represents the input parameter, target represents the current class, and returnObj represents the return value.

Stack to view the called path (up)

Stack com.sankuai.inf.leaf.server.service.SegmentService getId

Sc to view class information loaded by JVM

Sc-d com.sankuai.inf.leaf.server.service.SegmentService getId

Thread Analysis deadlock

Thread b

You can see that the current thread is waiting for ReentrantLock$NonfairSync@118f1fb4, and the thread holding this object is waiting for the current thread to be released, resulting in a deadlock!

Thread Analysis of CPU occupancy

Summary

Let's start with a big picture of the official summary:

Thank you for reading! This is the end of the article on "how to install and use Arthas". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, you can share it out for more people to see!

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