I have a Data-Driven Alert set to "Once - the first time it's true", watching a % Usage measure against an 80% threshold. The underlying calculation is tied to a rolling 12-month contract period (Aug 1–Jul 31) that resets automatically each year via TODAY()-based calculated fields — so % Usage climbs from 0% at the start of each contract year, and may or may not cross 80% before the year ends.
Example scenario:
- Contract Year 1: Aug 2026–Jul 2027. Usage crosses 80% in March 2027 → alert fires, one email sent.
- Aug 2027: new contract year begins, % Usage resets to ~0% (condition goes back to false).
- Contract Year 2: usage climbs again and crosses 80% in April 2028.
Question: In Year 2, once the condition goes false (Aug 2027) and then becomes true again (April 2028), will the alert fire again? Or does "Once - the first time it's true" mean the alert only ever sends a single email for the lifetime of that alert, regardless of the condition later resetting and re-triggering?
I haven't been able to find documentation that's explicit about whether "Once" re-arms on a false→true transition, or whether it's a one-shot for the alert's entire existence. Has anyone tested this across a reset cycle, or does Tableau document this behavior anywhere? Trying to decide whether I need to manually recreate the alert each year or whether it'll keep working unattended.
Tableau version: 2024.2.4
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