Table of Contents
# monitor
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Monitor method invocation.
Monitor invocation for the method matched with class-pattern and method-pattern and filter by condition-expression.
monitor is not a command returning immediately.
A command returning immediately is a command immediately returns with the result after the command is input, while a non-immediate returning command will keep outputting the information from the target JVM process until user presses Ctrl+C.
On Arthas's server side, the command is running as a background job, but the weaved code will not take further effect once the job is terminated, therefore, it will not impact the performance after the job quits. Furthermore, Arthas is designed to have no side effect to the business logic.
# Items to monitor
| Item | Specification |
|---|---|
| timestamp | timestamp |
| class | Java class |
| method | method (constructor and regular methods) |
| total | calling times |
| success | success count |
| fail | failure count |
| rt | average RT |
| fail-rate | failure ratio |
# Parameters
Parameter [c:] stands for cycles of statistics. Its value is an integer value in seconds.
| Name | Specification |
|---|---|
| class-pattern | pattern for the class name |
| method-pattern | pattern for the method name |
| condition-expression | condition expression for filtering method calls |
[E] | turn on regex matching while the default is wildcard matching |
[c:] | cycle of statistics, the default value: 120s |
[b] | evaluate the condition-expression before method invoke |
[m <arg>] | Specify the max number of matched Classes, the default value is 50. Long format is [maxMatch <arg>]. |
# Usage
$ monitor -c 5 demo.MathGame primeFactors
Press Ctrl+C to abort.
Affect(class-cnt:1 , method-cnt:1) cost in 94 ms.
timestamp class method total success fail avg-rt(ms) fail-rate
-----------------------------------------------------------------------------------------------
2018-12-03 19:06:38 demo.MathGame primeFactors 5 1 4 1.15 80.00%
timestamp class method total success fail avg-rt(ms) fail-rate
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2018-12-03 19:06:43 demo.MathGame primeFactors 5 3 2 42.29 40.00%
timestamp class method total success fail avg-rt(ms) fail-rate
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2018-12-03 19:06:48 demo.MathGame primeFactors 5 3 2 67.92 40.00%
timestamp class method total success fail avg-rt(ms) fail-rate
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2018-12-03 19:06:53 demo.MathGame primeFactors 5 2 3 0.25 60.00%
timestamp class method total success fail avg-rt(ms) fail-rate
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2018-12-03 19:06:58 demo.MathGame primeFactors 1 1 0 0.45 0.00%
timestamp class method total success fail avg-rt(ms) fail-rate
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2018-12-03 19:07:03 demo.MathGame primeFactors 2 2 0 3182.72 0.00%
# Specify the max number of matched Classes
$ monitor -c 1 -m 1 demo.MathGame primeFactors
Press Q or Ctrl+C to abort.
Affect(class count:1 , method count:1) cost in 384 ms, listenerId: 6.
timestamp class method total success fail avg-rt(ms) fail-rate
-----------------------------------------------------------------------------------------------
2022-12-25 21:12:58 demo.MathGame primeFactors 1 1 0 0.18 0.00%
timestamp class method total success fail avg-rt(ms) fail-rate
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2022-12-25 21:12:59 demo.MathGame primeFactors 0 0 0 0.00 0.00%
# Evaluate condition-express to filter method (after method call)
monitor -c 5 demo.MathGame primeFactors "params[0] <= 2"
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 19 ms, listenerId: 5
timestamp class method total success fail avg-rt(ms) fail-rate
-----------------------------------------------------------------------------------------------
2020-09-02 09:42:36 demo.MathGame primeFactors 5 3 2 0.09 40.00%
timestamp class method total success fail avg-rt(ms) fail-rate
----------------------------------------------------------------------------------------------
2020-09-02 09:42:41 demo.MathGame primeFactors 5 2 3 0.11 60.00%
timestamp class method total success fail avg-rt(ms) fail-rate
----------------------------------------------------------------------------------------------
2020-09-02 09:42:46 demo.MathGame primeFactors 5 1 4 0.06 80.00%
timestamp class method total success fail avg-rt(ms) fail-rate
----------------------------------------------------------------------------------------------
2020-09-02 09:42:51 demo.MathGame primeFactors 5 1 4 0.12 80.00%
timestamp class method total success fail avg-rt(ms) fail-rate
----------------------------------------------------------------------------------------------
2020-09-02 09:42:56 demo.MathGame primeFactors 5 3 2 0.15 40.00%
# Evaluate condition-express to filter method (before method call)
monitor -b -c 5 com.test.testes.MathGame primeFactors "params[0] <= 2"
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 21 ms, listenerId: 4
timestamp class method total success fail avg-rt(ms) fail-rate
----------------------------------------------------------------------------------------------
2020-09-02 09:41:57 demo.MathGame primeFactors 1 0 1 0.10 100.00%
timestamp class method total success fail avg-rt(ms) fail-rate
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2020-09-02 09:42:02 demo.MathGame primeFactors 3 0 3 0.06 100.00%
timestamp class method total success fail avg-rt(ms) fail-rate
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2020-09-02 09:42:07 demo.MathGame primeFactors 2 0 2 0.06 100.00%
timestamp class method total success fail avg-rt(ms) fail-rate
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2020-09-02 09:42:12 demo.MathGame primeFactors 1 0 1 0.05 100.00%
timestamp class method total success fail avg-rt(ms) fail-rate
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2020-09-02 09:42:17 demo.MathGame primeFactors 2 0 2 0.10 100.00%