Resolve #8001.

feature

Make the sampling rate mutable at runtime and can update the sampling rate temporarily.

How to use this feature

Method 1

This is the recommended method if you have 'the cluster feature' enabled.

Query/update the sampling rate from Pinpoint web UI.

The config "config.enable.samplingRate" in web need to be enabled, or all of the rate values would be 'N/A'.

Click the cell to edit sampling rate and press 'Enter' to confirm and update.

If you are using percent sampling type, the rate can be a decimal (xx.xx), 1(full sampling), 0 (disable sampling).
If you are using counting sampling type, the rate must be an integer (default max 100), 100(full sampling), 0 (disable sampling).

Method 2

This is the only method if you do NOT want to enable the cluster feature.

download arthas

$ curl -O https://arthas.aliyun.com/arthas-boot.jar
$ java -jar arthas-boot.jar <your running app pid>
arthas@pid >

Check the current sampling rate:

arthas > vmtool --action getInstances --classLoaderClass com.navercorp.pinpoint.bootstrap.classloader.ParallelClassLoader --className com.navercorp.pinpoint.profiler.sampler.SamplingRateSampler 

The output:

@SamplingRateSampler[][
@SamplingRateSampler[SamplingRateSampler{counter=12345samplingRate=20}],
]

Update sampling rate to 100%:

arthas > vmtool --action getInstances --classLoaderClass com.navercorp.pinpoint.bootstrap.classloader.ParallelClassLoader --className com.navercorp.pinpoint.profiler.sampler.SamplingRateSampler --express 'instances[0].updateSamplingRate(1)'

The output:

@SamplingRateSampler[][
@SamplingRateSampler[SamplingRateSampler{counter=12378samplingRate=1}],
]

It can also be scripted:

$ java -jar arthas-boot.jar -c 'vmtool --action getInstances --classLoaderClass com.navercorp.pinpoint.bootstrap.classloader.ParallelClassLoader --className com.navercorp.pinpoint.profiler.sampler.SamplingRateSampler --express "instances[0].updateSamplingRate(1)" ' <your running app pid>

Tasks

• sampling rate is updatable at runtime(without rebooting)
• sampling rate can be updated through external tool
• runtime sampling rate can be queried through collector/web by api
• sampling rate can be updated through collector/web by api
• sampling rate can be queried/update from web UI.

Changed module

• profiler
• agent
• collector
• web api
• web angular/ui
• grpc
• thrift (cluster communication)