Retroactive Instrumentation: When You Need More Detail

Sometimes you need detail you did not capture. The pattern of retroactive instrumentation: add it now, replay later.

The limit

Cannot capture data that was not emitted. The current incident's missing detail is gone forever.

But: similar future incidents will have the data.

What to do

Add the instrumentation now. The incident postmortem includes the instrumentation as an action item.

Verify in pre-prod that the new data lands correctly.

Compound

Each incident teaches what to add. Over years, instrumentation matches the actual debug needs.

Year 1: incident-driven additions. Year 3: most useful data is already captured before incidents.