Inconsistent datasource metrics configuration between MP Metrics and Micrometer

Describe the bug

The datasource documentation says

By default, this metric collection mechanism gets turned on for all data sources if a metrics extension is present and metrics for the Agroal extension are enabled.

and the all config options documentation indicate that

quarkus.datasource.jdbc.enable-metrics - If unspecified, collecting metrics will be enabled by default if a metrics extension is active.

However, when using the Micrometer extension quarkus-micrometer it is necessary to explicitly set quarkus.datasource.jdbc.enable-metrics to true, in addition to quarkus.datasource.metrics.enabled=true.

The reason seems to be that quarkus-micrometer does not declare to have the io.quarkus.metrics capability, the same way that the SmallRye metrics extension quarkus-smallrye-metrics does.

Expected behavior

Using the Micrometer extension quarkus-micrometer, Agroal datasource metrics should be collected after setting quarkus.datasource.metrics.enabled=true, with quarkus.datasource.jdbc.enable-metrics left unset.

Actual behavior

quarkus.datasource.jdbc.enable-metrics needs to be explicitly set to true.

How to Reproduce?

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Output of uname -a or ver

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Output of java -version

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GraalVM version (if different from Java)

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Quarkus version or git rev

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Build tool (ie. output of mvnw --version or gradlew --version)

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Additional information

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[jmartisk]

So the problem is that with SmallRye, metrics are enabled by default for all data sources, but disabled with Micrometer. The javadoc implies that they are enabled in both cases. If we’re not going to change the behavior, the javadoc should be changed, but I think it would make sense to unify this. If the global setting quarkus.datasource.metrics.enabled is true, and that needs to be set explicitly (!), why should we not enable them for all data sources by default? Most microservice apps only have one data source anyway.

[mjiderhamn]

The problem lies in DataSources.applyNewConfiguration … I don’t remember why MP Metrics is handled differently.

Yes, and as far as I could tell mpMetricsPresent was set based on the io.quarkus.metrics capability.