If trace sampling, metric can reflect the real situation of the system?

[chenhaipeng]

I've noticed that Skywalking metrics are generated based on traces. However, since traces are sampled, the metrics are not entirely accurate.

[wu-sheng]

Of course. What are you asking about?

[wu-sheng]

As same. I mean what do you ask for?

Of course, nothing to report, nothing to calculate.

There is no magic.

[wu-sheng]

Server side sampling makes sure the data accurate.
If you want to use agent sampling, of course, don't expect magic happens. There's not in the real world.

[chenhaipeng]

No reporting, no calculation. That's true. If metrics are distorted under trace sampling, and metrics are important indicators for system measurement, especially in transaction scenarios where sampling should not be used, is it a reasonable suggestion for Skywalking to have a custom self-reporting interface for metrics?

[wu-sheng]

There are metric plugin(for connection pool, etc.) and toolkit of meter, or you could use Spring lib

• https://skywalking.apache.org/docs/skywalking-java/latest/en/setup/service-agent/java-agent/application-toolkit-meter/
• https://skywalking.apache.org/docs/skywalking-java/latest/en/setup/service-agent/java-agent/application-toolkit-micrometer-1.10/