Is every log entry stored when using Application Insights custom logs?

Question

We know that Application Insights is not meant for collecting audit log entries.

But there is one legacy web application that have used Application Insights for logging audit type events. The application has been logging into traces table.

We are wondering if changing those log events to be custom logs (logEvent) which will then end up to customEvents table, how well it can be assumed that every log entry would be stored?

This documentation

https://learn.microsoft.com/en-us/azure/azure-monitor/essentials/metrics-custom-overview#design-limitations-and-considerations

says that "But if high cardinality is essential for your scenario, the aggregated metrics are probably not the right choice. Switch to using custom logs (that is, trackMetric API calls with trackEvent). However, consider that logs don't aggregate values, so every single entry will be stored."

https://learn.microsoft.com/en-us/azure/azure-monitor/app/api-custom-events-metrics#trackevent

Or is it still possible that Application Insights could use sampling at some level (adaptive sampling, fixed-rate sampling or ingestion sampling) also for custom log events, so that not necessarily every log entry gets stored into Log Analytics workspace table?

Answer 1

Hi,

You can check that customEvents table is not part of the sampling functionality by looking at the query to detect sampling. The query lists only tables requests, dependencies, pageViews, browserTimings, exceptions, traces.

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