For Azure Functions -
- Adaptive sampling is enabled by default.
- Fixed-rate sampling is not supported.
- Ingestion sampling only applies when no other sampling is in effect. Therefore, this is also disabled by default in the wake of point #1 above.
If you expect data (invocations) under Monitor but do not find it as shown in screenshot below, you have either changed Host.Results category to Warning (or above) level; or your application telemetry is getting sampled. To fix the former, open Host.json file and change the Host.Results category to Information level.
{
"logging": {
"fileLoggingMode": "always",
"logLevel": {
"default": "Information",
"Host.Results": "Information",
"Function": "Error",
"Host.Aggregator": "Trace"
}
}
}
If Host.Results category is already set at Information level, disable telemetry sampling as the next step.
To disable the sampling, set "isEnabled": false in host.json file as shown below -
{
"logging": {
"applicationInsights": {
"samplingSettings": {
"isEnabled": false
}
}
}
}
After disabling sampling, you can confirm it by running a query similar to the following; RetainedPercentage should show 100%.
At this point, the function invocations should start appearing under Monitor on Azure Portal UI.
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