Azure Application Insights Scalability

0
votes

When azure is hammered with several thousand records (for load testing), app insights does not show all traces and exception. The requests are certainly sent because there is corresponding data in the azure table. The querying was done using both Search and Analytics tab on Azure portal. Is this a known issue? What is the way/tool to view all traces, requests and exceptions?

1
azure-application-insights

1 Answers

0
votes

Your telemetry is being sampled. Either by ingestion sampling (happening at the Azure side), or by Adaptive Sampling (at the application side).

https://docs.microsoft.com/en-us/azure/application-insights/app-insights-sampling

The best recommendation I can make is to remove the AdaptiveSamplingTelemetryProcessor or just edit the parameters of it to suit your needs in the ApplicationInsights.config file.

Example 1

This limits the rate of ingestion to 1000 events per second, but does not apply any sampling to Dependency or Trace data

<Add Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.AdaptiveSamplingTelemetryProcessor, Microsoft.AI.ServerTelemetryChannel">
      <MaxTelemetryItemsPerSecond>1000</MaxTelemetryItemsPerSecond>
      <ExcludedTypes>Dependency;Trace</ExcludedTypes>
</Add>

Example 2

This limits the rate of ingestion to 500 events per second for Requests only. All other types are not sampled.

<Add Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.AdaptiveSamplingTelemetryProcessor, Microsoft.AI.ServerTelemetryChannel">
      <MaxTelemetryItemsPerSecond>500</MaxTelemetryItemsPerSecond>
      <IncludedTypes>Request</IncludedTypes>
</Add>

ExcludedTypes note on GitHub

IncludedTypes note on GitHub