Metrics appearing multiple times even if emitted once.

[arijitsurmicrosoft]

_metricCounter.Add(1, new("role", "mtproxy"), new("roleinstance", "azavsuatwebp101"), new("requestType", Constants.GET) , new("resultType", Constants.PIDPROXYPASS), new("durationMs","0"));

Hello everyone, the metric is keeping on emitting events even though the method (inside which this statement resides) is called only once.

[utpilla]

It looks like you're using ConsoleExporter which by default has a TemporalityPreference as Cumulative and not Delta. With Cumulative aggregation temporality, the MetricReader (ConsoleExporter in this case) would keep exporting the cumulated data for the metric with every collection. Metrics are reported for a certain duration. Note the start time and end time in the output. In case of Cumulative aggregation, the start time doesn't change and only the end time changes.

ConsoleExporter is only meant to provide you a fair idea of how the metrics data get emitted. There are a lot of backend systems that accept Cumulative aggregated data, the most prominent being Prometheus.

[arijitsurmicrosoft]

https://opentelemetry.io/docs/instrumentation/python/exporters/#temporality-presets

Thank you for your answer, I was expecting the same. Can you show me a doc which speaks about a way to set the temporalitypreference for exporters.
I used setx OTEL_EXPORTER_METRICS_TEMPORALITY_PREFERENCE DELTA
but i still see metrics getting emitted multiple times.

[arijitsurmicrosoft]

I have tried both setx and set, but i see the same output.

[cijothomas]

https://opentelemetry.io/docs/instrumentation/python/exporters/#temporality-presets --> This is a doc from Python OpenTelemetry. It won't work in .NET apps. (IIRC, the environment variable is not supported in OTel .NET)

[cijothomas]

https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/src/OpenTelemetry.Exporter.Console/ConsoleExporterMetricsExtensions.cs#L86

.AddConsoleExporter((exporterOptions, metricReaderOptions) =>
{
metricReaderOptions.TemporalityPreference = MetricReaderTemporalityPreference.Delta;
});

^ This shows how to change temporality for Console.

[cijothomas]

Once the delta/cumulative is changed, review the usage of metrics dimensions. It looks like one of the dimension is "durationMs", which is a bad choice for dimension. Durations should be the metric value itself, and modelling it as dimension would easily cause data loss due to cardinality capping https://github.com/open-telemetry/opentelemetry-dotnet/tree/main/docs/metrics/customizing-the-sdk#changing-maximum-metricpoints-per-metricstream

[arijitsurmicrosoft]

Thank you.