Sum aggregation with CumulativeTemporality shows as delta in metric explorer

[ktong]

The metric data metricdata.Sum[N]{DataPoints: points, Temporality: metricdata.CumulativeTemporality} is generated by opencensus bridge at https://github.com/open-telemetry/opentelemetry-go/blob/main/bridge/opencensus/internal/ocmetric/metric.go#L95. But it shows as delta metric so the value is stacked.

[dashpole]

Hey @ktong, thanks for reporting the issue.

A few questions about your setup:

• What is the graph above showing? Can you share the query you ran to get that graph?
• How is the OpenCensus metric being recorded (e.g. which package, or what instrument is being used to record it)?
• What version of opentelemetry-go and this repository are you using?
• Do you think this is an issue with this repository (something about our exporters), or with the bridge itself, or are you not sure?

Thanks!

[dashpole]

This may be related to open-telemetry/opentelemetry-go#3278, in which async counter values were treated as delta instead of cumulative.

[ktong]

Yes, it’s more likely caused by the issue.

[ktong]

Hey @ktong, thanks for reporting the issue.

A few questions about your setup:

• What is the graph above showing? Can you share the query you ran to get that graph?
  MQL

fetch k8s_container
| metric 'workload.googleapis.com/grpc.io/server/completed_rpcs'
| group_by 1m, [value_completed_rpcs_mean: mean(value.completed_rpcs)]
| every 1m

• How is the OpenCensus metric being recorded (e.g. which package, or what instrument is being used to record it)?

The View is defined at https://github.com/census-instrumentation/opencensus-go/blob/master/plugin/ocgrpc/server_metrics.go#L68

• What version of opentelemetry-go and this repository are you using?

go.opentelemetry.io/otel/metric v0.32.3
go.opentelemetry.io/otel/sdk v1.11.0
go.opentelemetry.io/otel/sdk/metric v0.32.3
github.com/GoogleCloudPlatform/opentelemetry-operations-go/exporter/metric v0.34.1

• Do you think this is an issue with this repository (something about our exporters), or with the bridge itself, or are you not sure?
  Not sure

Thanks!

[ktong]

The issue still exists while I upgrade go.opentelemetry.io/otel/sdk/metric to v0.33.0 which includes the fix of open-telemetry/opentelemetry-go#3278.

[ktong]

reported another issue in opentelemetry-go: open-telemetry/opentelemetry-go#3388

[dashpole]

Great. Looks like you found the problem

[dashpole]

Since the fix was merged upstream, i'm going to go ahead and close this issue. Feel free to reopen if you think there is more to be done.