[exporter/dynatrace] improve temporality documentation (#13370)

* [exporter/dynatrace] improve temporality documentation * Clarify that cumulative histograms are dropped * Clarify temporality for all instrument types * Clarify temporality configuration is on SDK * Update exporter/dynatraceexporter/README.md Co-authored-by: Joao Grassi <[email protected]> Co-authored-by: Joao Grassi <[email protected]>
open-telemetry · Sep 5, 2022 · 92994e3 · 92994e3
1 parent 3503509
commit 92994e3
Showing 1 changed file with 22 additions and 8 deletions.
diff --git a/exporter/dynatraceexporter/README.md b/exporter/dynatraceexporter/README.md
@@ -307,17 +307,31 @@ service:
 
 **Deprecated: Please use [default_dimensions](#default_dimensions-optional) instead**
 
-# Considerations when exporting Cumulative Data Points
+# Temporality
 
-When receiving Sum or Histogram metrics with CUMULATIVE temporality, this exporter
-performs CUMULATIVE to DELTA conversion. This conversion can lead to missing
-or inconsistent data, as described below:
+If possible when configuring your SDK, use DELTA temporality for Counter, Asynchronous Counter, and Histogram metrics.
+Use CUMULATIVE temporality for UpDownCounter and Asynchronous UpDownCounter metrics.
+When using OpenTelemetry SDKs to gather metrics data, setting the
+`OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE` environment variable to `delta`
+should correctly set temporality for all metrics.
+You can check the [spec compliance matrix](https://github.com/open-telemetry/opentelemetry-specification/blob/main/spec-compliance-matrix.md#environment-variables)
+if you are unsure if the SDK you are using supports this configuration.
+You can read more about this and other configurations at
+[OpenTelemetry Metrics Exporter - OTLP](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk_exporters/otlp.md#additional-configuration).
 
-## First Data Points are dropped
+## Considerations when exporting Cumulative Data Points
 
-Due to the conversion, the exporter will drop the first received data point,
-as there is no previous data point to compare it to. This can be circumvented
-by configuring the OpenTelemetry SDK to export DELTA values.
+Histogram metrics with CUMULATIVE temporality are NOT SUPPORTED and will NOT be exported.
+
+When possible, Sum metrics should use DELTA temporality.
+When receiving Sum metrics with CUMULATIVE temporality, this exporter performs CUMULATIVE to DELTA conversion.
+This conversion can lead to missing or inconsistent data, as described below:
+
+### First Data Points are dropped
+
+Due to the conversion, the exporter will drop the first received data point
+after a counter is created or reset as there is no previous data point to compare it to.
+This can be circumvented by configuring the OpenTelemetry SDK to export DELTA values.
 
 ## Multi-instance collector deployment