Having “invalid” data in production can lead to a whole range of wicked problems. I recently discovered that I must have added “Unique” under Data validation in my data model at a later stage of development without checking that the current data contained data that complied with the new rule.
I noticed the problem when I read data to a runtime data source and later wanted to persist the same set. Appfarm then returned an error message that the data violated the uniqueness rule. This happened because the runtime data-source contained data that was created before I ticked of “unique” and didn’t comply with the new rule.
It would be very nice if App health could discover uniqueness violations in data and warn me, so I can clean up the mess and avoid these kinds of silly problems.