I cannot find what start_at field in pa_snapshots form is

[jordimsant]

I am studying for my CIS PA exam and I bumped into something I do not really understand how it works. I have entered the pa_snapshots table and selected one random record just to see how the form is, and I think that I can understand what all fields refer to except for the start_at field. This makes me think of the following: How do indicators really use these snapshots? What does the start_at field stand for?

If anybody knows the answer to these questions, please tell me. If I finally find it, I will update this article.

[Uncle Rob · Accepted solution]

Snapshots collect sys_id's of records included in the indicator score.
If Number of New Incidents is 5, which 5 were they?  That's what pa_snapshot will answer.
Now, you're not meant to store pa_snapshots forever.  Basically the minimum amount of time where you stop being interested in the specific records and more interested in the trend data.

The system needs to know how far back to delete the pa_snapshots as they start to age out.
You might ask: "Why not just use the date the pa_snapshot was created", but that would only work for indicators that run daily.  Indicators that run monthly / quarterly, could delete pa_snapshots 30 - 90 days too early, since that's how much their created date and start_at properties will vary.

(if I run IndicatorX every month, it's created Dec31 and starts at Dec 1)

Hope that helps.  If so, pound that Correct Answer like the fist of an angry god.

[jordimsant]

Wow, now I understand, thanks for the answer, Uncle Rob!