Arthas tutorial

1. Official website tutorial

2.arthas-idea/ognl To configure
need idea Installing a plug-in arthas-idea

3. Use ognl Call method complex parameters ( You need to configure )
arthas-idea help

1 thread
thread -n 3/ Support one click display of the busiest previous 3 Thread and print stack
thread/ The default in accordance with the CPU Incremental time descending order , Display only the first page of data
thread –all/ Show all matching threads
thread -b/ Find out which threads are currently blocking other threads
thread -i 1000/ Count the recent 1000ms Threads inside CPU Time .
thread -n 3 -i 1000/ List 1000ms The busiest in the world 3 A thread stack
thread –state WAITING/ View threads in the specified state (WAITING/ wait for )

2 memory see JVM Memory information
memory/ see JVM Memory information

3 sysprop View the current JVM System properties of
sysprop/ See all the properties
sysprop java.version/ View individual properties ( Supported by TAB Key auto completion )
sysprop user.country CN/ Modify individual properties ( take user.country Modified into CN)

4 sysenv View the current JVM Environmental attributes of
sysenv/ View all environment variables
sysenv USER/ Look at a single environment variable

5-6 (vmtool,ognl) Complex parameter processing .

@[email protected]("{\"username\":\"y1y1\",\"password\":\"y1\"}",@[email protected])

5 vmtool vmtool utilize JVMTI Interface , Implementation call interface , Query memory objects , mandatory GC And so on

You can get spring Any object of

//vmtool -x 3 --action getInstances --className com.yjx.cloud.user.controller.api.ApiAppUserLoginController  --express 'instances[0].appLogin(@[email protected]("{\"username\":\"y1y1\",\"password\":\"y1\"}",@[email protected]))'  -c 9e89d68

6 ognl perform ognl expression

ognl -x 3 '#[email protected][email protected],#springContext.getBean("apiAppUserLoginController").appLogin(@[email protected]("{\"username\":\"y1y1\",\"password\":\"y1\"}",@[email protected]))' -c 9e89d68

7 watch You can easily observe the call of the specified function . The range that can be observed is ： Return value 、 Throw an exception 、 Enter the reference , By writing OGNL Expression to view the corresponding variable . watch See adding some default parameters , such as -x 3 an 3 The layer data

8 trace Method internal call path , And output the time consumption of each node on the method path
9 stack Output the call path of the current method to be called

10 monitor 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

11 jad Decompile class become java file

12 arthas Hot deployment processing

Save the data copied above to xxx.sh, Then go to the server to execute , Will automatically enter arthas Selection service process , Select the corresponding to class Thermal deployment

Other useful commands
•jad： Decompile a function , Generally, when there is a problem with the online code , See if it is when the code is released , Wrong version selected ; jad Class full name wildcard Function name ( Optional ) --lineNumber( According to the line Numbers )
•sc： View the loaded class information , This command is used when the bytecode is modified by a third party , Particularly useful sc Class full name wildcard Function name wildcard -d( details ) -f( Output class member variable information ) -E（ Turn on regular matching ）
•dashboard： Real time data panel of current system , Press ctrl+c sign out
•monitor： Method execution monitoring , Like every other 5 Count the execution times of a method in seconds , You can also execute input filter conditions monitor -c 5 -E（ Turn on regular matching ） Class full name wildcard Function name wildcard “params[0] <= 2”
•thread： View the current thread information , Look at the stack of threads , Such as thread -n 3
•jvm： View the current JVM Information
•sysprop： View the current JVM System properties of (System Property)
•sysenv： View the current JVM Environmental attributes of (System Environment Variables)
•vmoption： see , to update VM Diagnosis related parameters , Such as vmoption PrintGCDetails
•perfcounter： View the current JVM Of Perf Counter Information
•logger： see logger Information , to update logger level
•mbean： see Mbean Information about , This command can easily view or monitor Mbean Attribute information .
•getstatic： Direct use is recommended ognl command , More flexible . adopt getstatic Command can easily view the static properties of a class .
•ognl： perform ognl expression , Such as calling static functions ：ognl ‘@[email protected](“hello”)’
, Get static fields ：ognl ‘@[email protected]’
•sm： View method information for loaded classes , This command can search out all loaded Class Information method information .
•dump：dump The... Of the class has already been loaded bytecode Go to a specific directory , Such as dump -d /tmp/output java.lang.String
•heapdump：dump java heap, similar jmap Ordered heap dump function .
•classloader： see classloader Inheritance tree of ,urls, Class loading information ,classloader The order will JVM All of the classloader Statistics of the information , And you can show the inheritance tree ,urls etc. .
•mc：Memory Compiler/ Memory compiler , compile .java File generation .class.
•retransform： Load external .class file ,retransform jvm Loaded classes .retransform /tmp/Test.class
, adopt -d Parameter delete external class , adopt –deleteAll Delete all external classes
•redefine： Recommended retransform command ,redefine Command and jad/watch/trace/monitor/tt Waiting for orders to conflict . After execution redefine after , If you execute the above command again , It will put redefine Bytecode reset for . as a result of jdk In itself redefine and Retransform It's a different mechanism , Use both mechanisms to update bytecode , Only the last changes will take effect .
•trace： Method internal call path , And output the time consumption of each node on the method path ,trace Command can actively search class-pattern／method-pattern The corresponding method call path , Render and count all performance overhead and trace call links on the entire call link .
•stack： Output the call path of the current method to be called , A lot of times we know that a method is executed , But this method has a lot of paths to execute , Or you don't even know where this method was implemented , What you need at this time is stack command .
•profiler： Use async-profiler Generate flame chart ,profiler The command supports the generation of flame diagrams of application hotspots . Essentially through continuous sampling , Then the collected sampling results are generated into a flame diagram .
•cat： Print file contents , and linux Inside cat Command similar .
•base64：base64 Encoding conversion , and linux Inside base64 Command similar .
•tee： Similar to traditional tee command , Used to read standard input data , And output its content to a file .tee Instruction data from the standard input device , Output its contents to the standard output device , At the same time save it as a file . Such as ：sysprop | tee -a /path/to/logfile | grep java
•auth： Verify the current session , stay attach when , You can specify a password on the command line .

13 Application startup time analysis

start-up arthas Then select the corresponding service

Start by interrupting

profiler start --event cpu --interval 10000000

Let go of idea The breakpoint execution of spring Execute after startup

profiler stop --format html

Will generate a html file , Open it with a browser Analyze
The results are as follows , This diagram is commonly known as flame diagram , It mainly depends on the horizontal axis length of each method , The longer the abscissa is occupied , What it occupies cpu It's the longest , It's very intuitive

14 idea View the current Dump You can see the current occupation cup The long way