Version 1.34 metric oscillates

[DasMagischeToastbrot]

Describe the bug

We transform the traces to metrics (histogram) via the otel-collectors. We updated otel in our go code to version 1.34 and now when the metric (histogram) gets a high and a low value, it oscillates around both values. Until v1.33 the metric just counts up. In v1.34 we don't see this anymore, is there a default ttl in place now?

Environment

• OS: Linux
• Go Version: 1.23.0
• Version: v1.34

Customization: We use explicit bucket boundaries:

const explicitBucketBoundaries = []float64{0.025, 0.05, 0.1, 0.25, 1.0, 5.0, 60.0}

 handleSuccessHisto, _ = meter.Int64Histogram(
  "my-application.handle.success",
  metric.WithDescription("Successfully handled message metric"),
  metric.WithExplicitBucketBoundaries(explicitBucketBoundaries...),
 )

[dmathieu]

You mention these metrics are generated by the collector out of traces.
Do the traces have the same values as before? Is it possible the collector was upgraded around the same time as this?

0.34 includes an upgrade of the prometheus package, which include changes that could be surprising. Could this be the cause of your issue?
See the changelog for more details, and the mitigation.
https://github.com/open-telemetry/opentelemetry-go/blob/main/CHANGELOG.md#added

[DasMagischeToastbrot]

Yes the metrics get generated by a collector from traces. Yes the traces have the same value as before. We didn't upgrade the collector in the meantime. We

We assume that this upgrade of the prometheus package is the rootcause for this issue

[dmathieu]

But you're not using prometheus, since you're only emitting traces?

[DasMagischeToastbrot]

We are using prometheus, sorry I should have said it.

Our architecture is go application -> opentelemetry-agents -> opentelemetry-collector -> prometheus -> grafana

The opentelemetry-collector transforms the traces into metrics.

[dmathieu]

Right, but you're not using the prometheus exporter from this SDK. So you're not using prometheus.
Traces are basically raw data which is then transformed by your collector.
Unless you do see a change in the traces data being emitted, your issue has no way of coming from this SDK, since exactly the same data is being emitted.